PES Solar 1 18 Magazine

TALKING POINTComplexity solvedGround mounted PV systems in open spaces are it. For this purpose, algorithms wereincreasingly being built on hilly terrain and not only on flat developed to read out so called pointsurfaces such as farmlands or conversion areas. An clouds or contour lines in CAD files or asessential uncertainty is to accurately calculate the correct defined in the tachymeter data, and to beposition and length of the posts. PES was keen to hear able to map them inside the data structure.about Levasoft’s solution to this problem. Based on terrain data and the definition, the module layout of where to build the plant isIntegral software solution of the As the loads, of snow and wind, on the generated. Reference points are createdcalculation of statics and project design modules are distributed even more automatically, which are then used later asfor ground mounted PV systems irregularly to the terrain via the frame system, on site starting points for the installers. it is very difficult to find a homogeneousThis is critical, because of saving costs on design of the posts. Therefore, for variances Constraints to be taken in to accountmaterial and ramming. For us, this meant in the algorithms, the deflection moments ofthe further development of Solar.Pro.Tools the rails were analysed, and the strengths of Firstly the load determination for theprogram logic in order to be able to design the rails improved. The results have modules is done. Due to wind tunnelmodules or elevation systems in the terrain improved, but in some cases, they still lead reports, project location data such as windand to statically calculate these with to problematic interpretations. For this and snow load, as well as possible localalgorithms, which smooth the distribution reason, we began to develop a new concept conditions e.g. slope position, the area toof posts via linear programming. in order to simulate the calculation of the be laid out is divided into load zones. For rails and the positioning of the posts via a each individual module, the zone and theChallenge finite element method. position inside the composite are calculated and depending on this, the loadThe challenge to us was how the so called Another task was to read the terrain using on the module is determined in kN/m².PV system tables could be positioned in the three-dimensional data and basically modelterrain, without creating lots of individual Based on this result, the static calculationplants. Through iterative automated testing, is done – depending on the type of rack,we applied variances into the algorithms, insertion system or clamping system, thewhich, within parameters, merge adjacent loads will be distributed on rail pieces ormodules into tables, without creating new clamps. The clamps generate load pointstables. Another task was, if we could stillcalculate the distribution of posts in thisnew, three-dimensional system and ifpossible, would it be still performantenough to calculate even larger plants?This is the most complex problem withground mounted PV systems. Despite anextensive range of wind areas, irregularterrain, various components of steel andaluminium, a homogeneous distribution ofthe poles, which carry the assembled system,needs to be calculated in the end. So, weexpanded our concept with the ‘terrain’component, which led to terrible results. www.pessolar.com 51

TALKING POINTfor the rail calculation. After the rail done, based on exact longitude and latitude the area where the photovoltaic systemcalculation, the loads are passed down data, the result of our calculations could shall be built, the module layout is createdto the next position, further rail position lead to irregular patterns, due to an via a newly designed algorithm. So, theor subconstruction. optimised setting of poles. project planners only have to define where the system should start inside the definedThe loads must be converted again from The image of touching a spider’s web area. Constraints, such as the distancehorizontal to vertical loads or vice versa. serves very well to describe the challenge between the bottom and the lowest moduleEach bearing is assigned with maximum of this calculation. Once the position of one edge, are given before in the design tab.tensile, pressure and thrust loads, which can pole is changed or optimised, the The algorithm then starts with the firstbe placed against detection guides of the repositioning has an immediate impact on module, lifts it up so that the groundindividual components. Thus, each all other poles. The iteration through just distance is maintained and tilts it, as tiltcomponent can be detected exactly one row serves a huge quantity of possible was defined also in the design tab. Finally, itstatically. At the end of this process the static results immediately. Thanks to GUROBI is tilted to the right or left depending on theconditions of the horizontal constructions, Solver this problem can be solved in a terrain and to follow the terrain’s contour.the tables, are totally calculated. comparatively short amount of time. However, in order to achieve maximum The algorithm now proceeds with eachFinite elements and linear optimisation optimisation, this task will be done as a additional module as follows: Lift module to scheduled task and it is advised to start it ensure ground spacing. Tilt the moduleAs the Solar.Pro.Tool calculates rails as in the last phase of project planning. upwards for the angle of inclination modulecontinuous beams on pitched roofs e.g. this left/right tilt for the slope of the terrain.approach is, due to a possible strong It would be just too easy if this were the Check whether module before can becurvature of the terrain and a long only challenge. A changing terrain leads to connected to current module if yes, modulecalculation, process with bigger projects, even a more complex and takes some more is added to the table. If no, module createstransformed to the finite elements method. constraints in regard, such as maximum new table. All given space is used toThis method is based on differential bending, flexible table connectors, etc. complete the row. The next row is builtequations, solved by linear optimisation. upon calculated distance, given either by The planning process the planner or calculated by optimisedThis result serves as the basis for the value, based on shading, where the projectcalculation of the next technical layer, the When the terrain modulation needs to be location geo data is taken in regard.poles. Mounting the poles is one of the taken in account, geo data needs to bebiggest cost drivers for ground mounted claimed. This can be done based on sources After the module design is complete, eachsystems. So, here maximum economic like NASA, geo information data or manual module generates its direct connection tooptimisation must be accomplished, within topography data. Once imported inside the racking itself. Then all componentsthe boundaries of standardisation, fast Solar.Pro.Tool, a 3D object is generated. (rails, beams, posts) of the mountinginstallation and stability. Another challenge Each point is defined by its coordinates system are automatically generated and thecan also be the number of required poles, (X,Y,Z) and by its longitude and latitude. statics calculated.which is also determined by their groundingtype and the ground conditions themselves. After reading the terrain data and defining The result contains different plans forVisually the calculation needs to be done ramming / drilling, mounting and wiring. Thefrom both sides. plan for ramming or drilling is also extended with a table, which contains all points andViewed from top to bottom, after the statics directions. This data can be exported to beof rows are calculated, the input used for software driven ramming or drillingparameters are given by the different loads. machines and for a later verification of theConstraints are given by these, plus others, correct positioning of all poles.such as the maximum table size, tableconnections, possible maximum cantilever The aggregation of all features andarm lengths, etc. It would be simple to calculations makes Solar.Pro.Tool a timeregard a row as just one solitary technical and money saving asset for ground mountconstruction, and just set poles in a project design. It eliminates the gapcontinuous pattern. This would be safe, but between project design and structuralwould lead to a non-competitive result. engineer calculation. It reduces manual input to a minimum and delivers maximumAs the poles ramming or drilling can be documentation automatically. www.solarprotool.com52 PES Solar

12RWould You Use a Pocket Calculator -To Optimise a Multi-Milllion Variants?At Levasoft, we are taking the calculation of statics Solar.Pro.Tool is using cloud-computing to calculatevery seriously. The nature of Solar.Pro.Tool is to deliver these multi-million possible variants in just a fractionstatics in the most sophisticated, accurate and of a second.transparent way to do this as a background-service. Use Solar.Pro.Tool for your complete project-designIt just happens, while you are designing - and be welcomed to safe and easy.and it happens very fast. Now available for ground-mounted systems too.Solar.Pro.Tool - The Most Complete ProgressivenessLevasoft GmbH | Sterneckstr. 6 | A-9020 Klagenfurt | www.solarprotool.com | +43 720 35 19 20

ASK THE EXPERTSSILEX II 4908 detailThe quest for betterperformance and cost savingsDr.-Ing. Stefan Rinck, CEO Singulus Technologies AG, caught gallium diselenide (CIGS), cadmium tellurideup with PES to tell us about the latest business activities and (CdTe) vacuum deposition equipment andtechnology.This is a company which makes a significant equipment for wet-chemical processing.contribution to the solar/PV market. It is innovative and The field of activity of crystalline solar cellsalways strives to improve performance and save costs. includes production solutions for high- efficiency solar cell concepts such as HJTPES: Welcome back to PES Solar/PV engineering, wet chemistry, and thermal (heterojunction), IBC (interdigited backmagazine. Thanks for talking with us. processing technologies. contact) and PERC (passivated emitter rearWould you like to begin by explaining a cell) solar cells.little about the background of The company’s primary focus is on theSINGULUS TECHNOLOGIES AG and how solar, optical disc, and semiconductor PES: Can you please give us an updateyou currently serve the solar industry? applications, with particular attention to on changes, especially in your copper consumer goods and medical technology in indium gallium selenide solar cellsStefan Rinck: SINGULUS TECHNOLOGIES the future. (CIGS), over the last 18 months?AG’s business activities centre ondeveloping, manufacturing, and marketing In the solar segment, SINGULUS SR: Our biggest customer in China, themachinery and equipment in the fields of TECHNOLOGIES AG offers machinery for state-owned China National Buildingvacuum coating technology, surface manufacturing crystalline solar cells and Materials (CNBM), has already started thin-film solar cells based on copper indium construction work on four domestic production sites for CIGS thin-film solar modules. The planned output volume for each factory at the end of the first phase of54 PES Solar

ASK THE EXPERTSexpansion is around 300 MW. The plan is to TENUIS II presents another promising PES: What are the benefits to yourcomplete further expansion phases over the development on the way to the efficient clients and the end users?next few years to increase the output volume wet-chemical coating of thin film solarat each location to around 1,500 MW, modules made of CIGS on glass. SR: Signing the major order in May 2016,creating capacity of 6,000 MW in China. Due to the unique concept in terms of comprising six agreements on the supply of dosing and temperature control, the systems for CIGS solar module production,The contracts for the machine systems to developers at SINGULUS for two different factory sites in China, wasbe delivered by SINGULUS TECHNOLOGIES AG were successful in an initial major success story for ourTECHNOLOGIES AG for the first two reducing the process time, which in turn Company in this regard.production sites in Bengbu and in Meishan, has a positive effect and a meanswere signed in May 2016. The systems for considerably higher output in production. Not least due to our sound operationalthe Bengbu factory were delivered last year base, this venture saw us take a major stepand will be available for production in 2018. Selenius CIGS to refine and successfully complete furtherWe delivered machinery to Bengbu with projects. Indeed, in the 2017 fiscal year, weselenisation furnaces, sputtering systems managed to secure further orders in CIGSand evaporation systems, all of which are solar technology, from two majorkey production steps for manufacturing manufacturers.CIGS solar panels. So, SINGULUS TECHNOLOGIES AG isFor the second site, construction of the certainly a leader in the solar market. Wesystems began after receipt of the agreed have already delivered several of theseprepayment and is expected to be largely systems to the market and they are workingcompleted by the end of 2018. We are around the world. Our customers can thustalking with CNBM about the investment for be sure, that we have a lot of experience inthe other two factories. providing excellent manufacturing solutions for the different CIGS-processes.Our company is also active in other projectsfor the setup of CIGS production facilities. PES: Let’s move to the big market forIn 2017 we signed contracts for the delivery crystalline solar cells. What is the latestof VISTARIS vacuum sputtering systems, as on HJT?well as systems for wet chemical bufferlayer deposition with the brand name SR: Developments on the market forTENUIS II. Buffer layer deposition with high-efficiency crystalline solar cells based on heterojunction technology were a particular focal point. The Chinese government is promoting the local establishment of production capacities in photovoltaics for HJT. SINGULUS TECHNOLOGIES AG offers the market’s leading wet-chemical system for the production of these HJT cells, SILEX II, and has placed the second key production step on the market with the inline sputtering system GENERIS PVD. Looking ahead to the future, the market for these high- efficiency cells is estimated to account for a volume of more than 20 GW a year. SINUGULS TECHNOLOGIES AG started with the wet processing tool SILEX II, which was introduced to the market in 2014. Since then, we have worked intensively on developing www.pessolar.com 55

ASK THE EXPERTS Linex detailLinex 10 Generisthe SILEX II system, for high-efficiency process enables optimum layer environmentally friendly sawing process iscrystalline solar cells. Our company has performance at temperatures ≤200°C. extremely faster compared to the standarddelivered systems to be used in With the GENERIS PVD sputtering system, slurry cutting processes. This increasesheterojunction cell manufacturing to Europe, contact layers can be deposited on the production output significantly andthe U.S. and Asia. In October 2017 we front and rear of the Si wafers without the maximises machine capacity. The marketreceived new orders for SILEX II processing need to turn the wafers between coating for multicrystalline solar wafers is expectedsystems from China and the USA. processes and without vacuum to continue to rise next year, with a growing interruption. Annealing of sputtered layers proportion of wafers processed usingThe SILEX II concept ticks all the boxes is optionally integrated. Also, full area diamond wire saws.regarding capacity, flexibility and stability in metal coatings, e.g. Ag can be depositedthe industrial manufacturing of Si solar within the same system. This new innovative manufacturing processwafers and cells. Capacities of up to 6,400 from SINGULUS TECHNOLOGIES AG,wafers or cells are possible. Compared to Some details about the system: The incorporates two distinct steps developedconventional etching systems, the SILEX II GENERIS PVD system features a transport in-house: the use of new additives andoffers significant cost benefits, thanks to system out of vacuum – there is no particle ozone for post-cleaning resulting in the bestthe use of ozone-based processes. The generation and substrate heating is possible. cost-effective method on same footprint assystem has achieved CE certification for the former standard texturing systems. TheEurope, Ul certification for the USA and All vacuum chambers are made out of texturing of solar wafers is a manufacturingalso TR CU certification for Russia. stainless steel – this leads to an excellent step that has an influence on the efficiency vacuum performance with a higher heating of the solar cell. The innovative LINEX inlineOur company now has also developed a temperature. The built in rotatable processing system for wet-chemical surfaceuniversal sputtering platform with the brand sputtering magnetrons provide highest treatment is equipped with the newname GENERIS PVD. The newly developed target utilisation. combined process, thereby saving costsGENERIS PVD system is a horizontal inline significantly and improving cell performance.sputter tool designed for the special Furthermore, the GENERIS PVD systemrequirements in photovoltaic high efficiency offers reduced manufacturing costs and the The SINGULUS TECHNOLOGIES LINEXHeterojunction cell technology providing high uptime offers a higher machine system combines an advancedconversion efficiencies of more than 22 % performance and leads to reduced cell transportation system and sustainable/as well as reduced manufacturing costs. cost. The GENERIS PVD system with a innovative processing modules with proven modular chamber setup provides a and efficient chemical treatment.The GENERIS PVD is ideally suited for throughput range from 2600 wph up tochallenging layer stacks i.e., TCO layers like 5200 wph. In addition to proven processes, the focusITO and AZO providing maximum optical is on new applications such as Inlinetransmittance, matched refractive index, PES: We would love to hear about other Alkaline Texture for Mono-PREC single sideoptimum electrical conductivity as well as applications, PERC for example. process, polish etching, and ozonecharge carrier mobility, all of which are key applications. The highly integrated design,parameters in heterojunction cell technology. SR: We brought a new texturing process to high throughput, high availability and low machine multicrystalline solar wafers to breakage rates make LINEX very attractiveSputter damage to the amorphous silicon production readiness. Diamond wire sawing for solar cell manufacturers worldwide.layer stack does not occur. A full substrate is significantly cheaper since it is faster andtemperature control during the whole reduces the waste of silicon. The The LINEX DW Texture is a modular tool56 PES Solar

based on an inline platform that supports Vistaris basis ASK THE EXPERTSeasy integration into existing production VISTARIS CIGSlines cells without any additional facility ‘We combine the correspondingrequirement. The system is available in two process technology with innovativeversions - 5 or 10 lanes. This inline toolmoves the wafers in 5 or 10 parallel tracks solutions for production facilities.’and has a rated throughput of 4200 to9000 wafers per hour, with a breakage rate www.pessolar.com 57of <0.05%.PES: Speaking from a global standpoint,which geographical regions do you wantto move in to?SR: The market research firm BloombergNew Energy Finance (BNEF) predictedsimilar installation figures for the globaltotal market. According to their forecast,global photovoltaics installations will reachat least 107 GW in 2018. The BNEF forecastshows China again dominating the trend byadding capacity of between 47 and 65 GWin 2018. Furthermore, regions such as LatinAmerica, the Middle East and Africa makeup a measurable share of the total volume.PES: Looking to 2018 and beyond, whattrends and/or changes are youanticipating in and why?SR: The Solar market will be our key marketfor the future as well. The corecompetences of SINGULUSTECHNOLOGIES AG lie in the areas ofvacuum coating technology, wet-chemicalprocesses, surface technology and thermalprocess technologies. We combine thecorresponding process technology withinnovative solutions for production facilities.The company’s strategy is to use thisexpertise to increase our market share inexisting markets and to transfer ourexpertise to additional markets and acquirenew customers.One of the clear aims for the near future isto make further in-roads into the solarmarket and maximise the potential offeredby the renewable energy sector worldwide.By integrating our various processtechnologies and experience in the variouscell technologies, we can offer efficient andcost-effective production processes for thenew solar cell concepts. This means thatSINGULUS TECHNOLOGIES AG has thetechnological foundation and the skillsneeded to play a key role as a globaltechnology provider for the photovoltaicsector in the future.We will continue to use and expand our corecompetences in the aforementioned surfacetreatment technologies in the semiconductorsegment, and also apply them to productionfacilities for consumer goods and inparticular, medical technology sector in atargeted manner in the future. We areworking on testing further applications forthese two new fields of activity so that it canaddress all available market opportunities inthe best way possible. www.singulus.com

It all starts withinnovation.A smart grid needs a smart Smart engineering means APsystems microinverters havemicroinverter – and APsystems 30 percent fewer components than competing brands,sets the standard worldwide with meaning higher reliability and lower costs at every point inthe new YC600. the production and distribution chain. On the production line, quality is top priority thanks toA smart grid needs a smart microinverter – and APsystems strict and systematic control, including Automatic Opticalsets the standard worldwide with the new YC600. Inspection (AOI), Functional Test Checks (FCT), and burn-With its groundbreaking design and features and an in testing for every unit coming off the line. To ensureunprecedented 300VA peak output per channel, the YC600 optimum performance in any climate, APsystems productsis the new pinnacle of microinverter technology. A true utility- go through rigorous Quality and Reliability Verification Testsinteractive microinverter with Reactive Power Control (RPC) and simulations, including high-low temperature extremes,technology, the YC600 meets the most advanced electrical salt-spray tests and waterproofing, drop and vibration trials.requirements around the globe including VDE-AR-N 4105 for APsystems is proud to use Kanban, 5S and Six SigmaGermany, CA Rule 21 for California and is inherently NEC principles and JIT inventory management, as well as ISO2014/2017 Rapid Shutdown compliant. 9001 certified processes.The single-phase YC600 serves two modules with dual, In the field, all APsystems products comply with regional andindependent MPPT. ZigBee wireless communication over local certifications and grid regulations, holding certificationsa mesh network offers faster data speeds than PLC and a in markets worldwide including AR-N 4105, CQC, CSA, CD,wider MPPT voltage range for greater energy harvest SAA and ETL, as well as VDE 126-1, G83-2, NRS 0972-1,for homeowners. and EN50438. No wonder that with hundreds of thousandsIt’s the level of innovation you’ve come to expect from of units installed in more than 80 countries around the globe,APsystems, the company that revolutionized the residential APsystems installations have produced more than 130 GWhModule Level Power Electronics (MLPE) segment with the of clean, renewable energy.YC500, the world’s first dual-module microinverter and the APsystems has also been a solid corporate performer,installer’s choice – then did it again with the YC1000, the first- profitable every year as a leader in the fast-growing MLPEever true 3-phase, 4-module unit for commercial applications segment, a trusted partner for distributors and installersand still the top seller in its product class. around the globe.But it’s not enough to be the first. You need a commitment Innovative, reliable, powerful and proven – that’sto be the best, and APsystems reliability leads the pack. APsystems.With 50 percent of its global workforce dedicated to productengineering, design and development, the completeworkforce is committed to excellence in allperformance standards.

Find out why it’s being called the most advanced solar microinverter in the world.YC600The all-new  Dual-module  Highest peak power  ZigBee wireless 3x microinverter with output of 300VA per faster than PLC independent MPPT per channel panel  Meets NEC 2017  VDE AR-N 4105 and CA 690.12 Rapid Shutdown  Utility interactive with RULE 21 requirements Reactive Power Control (RPC)  More PV modules per  Accommodates panels string than comparable from 200W-365W+  IP67 enclosure microinverters POWERFUL I N N O VAT I O Nemea.apsystems.com | [email protected]

THINK TANKAdvanced weather monitoringsolutions for irradiancemonitoring and forecastingWords: Dr. Mario Po, EKO Instruments Europe B.V.The price of photovoltaic (PV) systems continues to decrease, concept of Smart Grids, in whichadding PV as a cost effective cleaner energy solution. While interconnectivity and live data sharingsolar photovoltaic grid penetration increases worldwide, new between both the devices producing andtechnical challenges arises in the electric grid side. Little consuming electricity allow a betterprogress has been made to incorporate managing schemes in understanding of demand and supply ofsolar power systems to improve the utility management. electricity. Additionally, the storage systems, one of the missing links to thePV growth, its drivers and implications of electricity demand are currently under efficient solar power integration, areto the grid study and are now becoming attractive due following the same trend as PV in terms of to cost effectiveness of PV. cost reduction, opening new possibilitiesHowever, many technological solutions for managing the energy sector.have been presented to facilitate the grid Developments in electronic house holdside. For example, using bifacial PV appliances now also offer the possibility of Managing the energy flow from a solar powermodules setup vertically to shift the electric connecting a device to the internet and plant requires an effective solar monitoringenergy generation peaks to match the peak communicate with the grid, realizing the system to characterise the available solar energy resource for electricity generation, and this involves a comprehensive set of equipment. By means of providing a diversified set of measurement instruments60 PES Solar

THINK TANK MS-90 direct normal irradiance sensor Novel technology to measure DNI suitable for solar energy monitoring and meteorological applications. The state of the art setup to measure the DNI is comprised of one pyrheliometer Spectral irradiance data sets are critical to assembled in a sun tracker, such as the many environmental science and energy EKO MS-57 thermopile pyrheliometer applications. To acquire reliable in situ assembled in an EKO STR-21G Sun tracker. spectral irradiance data, ground based A new low-cost solution that does not spectroradiometers are commonly require a sun tracker has recently been deployed. The state of the art spectral DNI introduced by EKO. The MS-90 is based on is measured by continuously tracking the an innovative method with rotating mirror, sun during the day, and pointing a which reflects the sunbeam onto a thermal collimated spectroradiometer, so that only detector. Both thermal sensor and mirror the sun rays that come straight from the employed have a nearly flat spectral sun disk are measured by the detector. characteristic responding well to changes in the solar spectrum, presenting a solution For spectral measurement of the three irradiance components we took a differentfor all weather monitoring, EKO stands ready MS-711 Rotating Shadow Band Spectroradiometerto assist the industry and research in solarenergy projects.The international standards for PV systemmonitoring (IEC 61724-1) define criteria howto perform actual measurements of solarirradiance and meteorological parameters.Having quality measurements aids indeveloping a dataset that allows thedecision makers to effectively optimize theirpower generation periods. It is commonpractice quantify the solar energy in termsof global horizontal irradiance (GHI), planeof array (POA), diffuse horizontal irradiance(DHI), and direct normal irradiance (DNI).Depending on the application, acceptablelevel of uncertainty and cost, differentapproaches can be pursued to measureeach component. www.pessolar.com 61

THINK TANKSTANDARD OPTIONAL OPTIONALSet-up and control software Imager performs all- Find-clouds software. The Find Clouds software Cloud-base height software Using two ASI-16weather acquisition of high-resolution images with allows the calculation of the sun position imagers and the additional CBH software, anetwork storage, stereoscopic method can be applied to a pair of synchronized images to determine the cloud- base height.approach. A Rotating Shadow Band (RSB) aspects, more advanced weather monitoring Rotating Shadow Band positionsspectroradiometer configuration offers an systems, which are capable of forecastingalternative to tracking, which lowers the solar irradiance and anticipate power Different environmental conditions can becosts associated with the instrumentation production, are of most importance. experienced depending on the site location.required, and, since only one detector is Accurate forecasting of irradiance will permit The standard ASI-16 Sky Imager is capableused, it also minimises the discrepancies forecasting power drops in PV plants, of operating under harsh environmentsassociated with sensor calibration and the presenting enormous potential to improve from temperatures as low as -40°C up tomutual differences regarding measurement dispatchability, and optimise grid stability. 50°C, with an integrated ventilation andperformance when measuring the spectral heating system, which also preventirradiance components. Current schemes for forecasting irradiance condensation on the dome surface and are based on satellite cloud observations promote the fast removal of raindrops andAccurate results of the DNI measurements with numerical weather prediction. While snow. Furthermore, the imager is poweredcan be obtained from a MS-711 these methods can provide information up to over Ethernet (POE), with a durable andspectroradiometer with RSB comparing several days in advance, from approximately waterproof cable.with the MS-711 DNI spectroradiometer on 10 to 100 km2 spatial resolution, thea sun-tracker. The comparison between the information still carries significant errors in Environment temperature and humidityoutputs spectral DNI from the two the estimated irradiance. A path to get sensors are also incorporated in the device,configurations reveals a consistency in the higher intra-hour temporal resolution and with the possibility of connecting onemethods and provides all 3 irradiance forecasting, with higher spatial resolution of EKO’s irradiance sensor via Modbuscomponents. EKO will provide the RSB can be achieved by means of ground-based communication protocol, the synchronoussolution for all spectroradiometer models. measurements such as cloud cameras and data acquisition of several weather radiation sensors spread out and operatingNew eyes on the sky within a network.With the solar resource depending on For such a forecasting scheme all weatherlocation and time of the year, the solutions to monitor clouds are becomingcharacterisation of the solar energy one of the most desirable solutions. Withresource is crucial for solar energy the new ASI-16 All Sky Imager, EKO offersapplications. However, with variable an advanced solution for cloud monitoring.weather conditions the energy output from New eyes on the sky are in demand in ordersolar power plants becomes quite complex, to optimize and forecast the energy outputpresenting large impacts and concerns for from solar power plants.the utilities operation during the passage ofclouds, and although monitoring irradiance Designed to withstand all weatherin situ already provides significant conditions, the ASI-16 All Sky Imagerinformation for operation and maintenance, features a digital camera and fish-eye opticsit is not sufficient to anticipate changes in with a 180° field of view assembled under airradiance and assist utilities to respond to robust coated quartz dome, avoiding sensorthe variability. degradation due to direct exposure to the sun and allowing the automated acquisitionClouds have generally an attenuating effect of high dynamic range (HDR) images of theon the irradiance, which are dependent on hemispherical sky.the cloud characteristics. To cover these62 PES Solar



THINK TANK cloudiness. Using different algorithms to B C calculate cloudiness, the cloud analysis AASI-16 All Sky Imager software, allows the calculation of the sun position in the image as well as to run A. ASI-16 all-sky imagerparameters is simplified, removing the need algorithms such as the blue/red and blue/ B. MODBUS communicationof having an independent datalogging green channels ratio (BRBG), and the cloud C. MS-80 Pyranometersystem and facilitating the instrument detection and opacity classification (CDOC),deployment on site. The users can have full to quantify cloudiness on the image set.control of the imager to perform settings,data acquisition, visualization, and storage, Cloud base heightwith a web browser-based manager withlive video stream and network storage. Further characterization of the clouds can be achieved by determining the clouds baseThe sky imager is complemented with the height (CBH), allowing the possibility ofFind Clouds software, in which the images estimating the shadows casted by theacquired with can be processed to classify passing clouds. Using a stereoscopic method, the CBH can be measured with two ASI-16 Sky imagers, where an additional Cloud Base Height software is available to process time synchronized images of two imagers set up at nearby locations. The features and tools provided with the ASI-16 All Sky Imager make it an innovative solution for cloud monitoring. As additional software tools are under development, more features for this imager are coming soon. For the solar energy industry more advanced monitoring tools are needed to forecast the amount of energy that solar plants will produce in the short term. EKO is keen to develop new applications and create this value. www.eko-eu.com64 PES Solar

Greening theSolar Industry WATER . CHEMISTRY . ENVIRONMENT . Pictures: Loser Chemie GmbH, andreas160578, rawpixel under Creative Commons Licence CC0Chemieƒ Greening the Solar Industry with PV-Recyclingƒ We have the technology and we build the plantƒ We can treat thin film and Si-based End-of-Life PVƒ Proven history of successful waste managementVisit us in Munich Visit us in San Francisco June 20-22 July 10-12 Booth B3.350 Booth 7431 Loser Chemie GmbH ƒ A company of LFFICIENCY [email protected] ƒ www.loserchemie.de/en ƒ ( +49 375 27476-0

TALKING POINTFlexibility makes thedifference to residential solarMore and more home owners are installing PV systems. Flexible by designHow efficient are these systems? What does the industryneed to do to support this growth area? PES takes a look at Although innovation by industry andHuawei’s new, flexible solution. economies of scale are contributing to cost reductions across solar, for homeowners, aAcross solar markets globally, we are expansion of commercial projects, home energy system can still represent acontinuing to witness the maturation of residential photovoltaic applications will be significant upfront financial expense. It isutility scale solar, with subsidy-free a key growth engine for the industry in the therefore imperative that any residentialcommercial projects increasing in coming years. Industry experts at IHS solar solution is able to account for differentfrequency. As solar’s share in global energy Markit forecast that 48 GW of residential PV residential layouts and uniquegeneration continues to rise exponentially, systems will be installed globally within the circumstances of the homeowner.the industry’s ability to innovate expands next five years, almost doubling the globaltoo. The rapid technological developments installed base for residential solar to 90 GW Although residential PV systems are muchand cost reductions that have been driven by the end of 2021. smaller in scale and capacity than their utilityby investment in utility scale are also having scale counterparts, they still present theira positive influence on the growth of the The growth of residential solar is just one own set of particular challenges. Taking theresidential sector. example of how the global energy system is variability of rooftops, for example, there are becoming increasingly decentralised. The several characteristics of a rooftop whichFrom an industry perspective, this growth use of renewable technologies and other need to be considered, including thehas been accompanied by a proliferation of forms of decentralised energy continue to complexity of the layout, shading and theresidential PV systems and technologies expand, with countries moving away from most efficient string configuration.now available to installers and traditional models of generation fromhomeowners. So with residential solar now conventional sources. As this system These factors can be compounded furtherset for another significant period of develops across markets, flexibility will be by limitations with respect to PV systemexpansion, it is essential that PV technology the defining characteristic of the new era of design, which result in a sub-optimal use ofdevelopers are able to offer systems that energy generation, in terms of distribution, roof space. Previously, PV systems wouldcan handle the huge variety of customer storage and consumption. require that all PV modules in one stringdemands across what is an increasingly had to face the same direction and couldcompetitive and crowded marketplace. Typically, when discussing the subject of not be located in shade-prone areas. flexibility with respect to solar, it’s inThe growth of residential relation to how the application of digital Similarly, individual strings would require technology and smart management have identical module type while parallel stringsPreviously, residential solar was supported transformed an intermittent form of had to be identical in length. Without theby necessary financial incentives in order to generation into one of the most responsive appropriate PV system design these factorsprove attractive to homeowners. As we look forms of electricity supply. When it comes can have a significant impact on both theat the costs of a typical residential PV to residential PV systems, however, it is the upfront cost and energy yields over thesystem in some of the most developed flexibility of system design that will be a lifetime of the system, having a direct effectsolar markets, many are now at the level priority for both installers and for on a customer’s return on investment.that already makes economic sense on homeowners who are looking to invest intheir own. Consequently, market analysts home energy solutions. To avoid these issues, Huawei hasare predicting that following the rapid designed its FusionHome Smart Energy Solution from the bottom up to be a one-fits-all solution, which has the flexibility to meet the range of customer requirements across the residential market. By helping to66 PES Solar

TALKING POINTsimplify these design issues, it enables require that optimisers be installed across Storage will help facilitate new ways forcustomers to maximise rooftop kWh yields an entire array even though they may only consumers and businesses to manage theirin all scenarios. The system is built around be needed on one module. For those energy while enabling industry andan inverter with European-weighted customers who require a more governments to reimagine how we canefficiency of 98%, which also comprehensive set-up, the system can be utilise the grid.accommodates the use of PV optimisers on scaled up and optimisers can be combinedselected modules that may have shading or with safety and module management to Consequently, batteries are set to be one ofdifferent roof orientation. offer a fully functional solution. the fastest growing segments of the solar industry. An ever-increasing proportion ofThe smart optimiser effectively avoids For installers and distributors, the benefits solar and wind on the grid, combined withmodule mismatch caused by dust, of flexible residential systems are obvious. the continued expansion of battery electricshadows, PV module attenuation, and hot Being able to offer a solution that they know vehicles is helping to drive down batteryspots and maximises the energy yield from can cope with the full range of requirements costs, with the price of lithium-ion batteryeach PV module. Taking a rooftop that may across the market means that they no packs having fallen 79 per cent since 2010,have a chimney-shaded area equivalent to longer need to purchase multiple solutions according to Bloomberg New Energythe size of four modules, for example, from different suppliers, which helps to Finance data.FusionHome allows homeowners to install significantly reduce operation costs. Inmodules with optimisers in the shaded area addition, installers only need to contact one Despite the positive trajectory that theenabling them to fully utilise their rooftop. supplier, helping to deliver savings across storage market is on, it currently remainsOver 25 years these four modules can marketing, logistics, warehouse, team the case that storage still represents agenerate around 22,400 – 33,600 kWh in management and communication. sizeable financial undertaking foradditional yields, comfortably covering the customers. As such many homeowners willupfront cost of the modules. Future-proofing for storage understandably be looking to defer this cost until the price of batteries furtherImportantly, FusionHome has the Another way in which it is essential that the decreases. While this is an attractivefunctionality to enable customers to only industry is able to offer flexibility to option, adding batteries later may result inadd optimsers where needed. This helps customers is energy storage. The advent of customers encountering additional costs,customers keep costs down when reliable storage technology will be a central or complications depending on thecompared with other systems, which aspect of the new global energy system. capabilities of their PV systems. www.pessolar.com 67

TALKING POINT ‘In a highly competitive marketplace, the task at hand for PV technology manufacturers is to continue innovating and investing to ensure that they can offer a solution that is suitable for all customer scenarios that maximises yields while minimising costs.’ Hybrid inverters, which are capable of storing energy directly into batteries, are prohibitively expensive, while other systems require system retrofit and the purchasing of additional AC/DC conversion modules before batteries can be added. To provide homeowners with greater choice over when to invest in storage, Huawei’s FusionHome features an integrated DC-coupling storage interface. This offers plug and play functionality, enabling customers to conveniently add batteries at any time. This eliminates the need for retrofitting and the costly purchasing of additional equipment. In order to ensure optimum efficiency the interface is DC-coupling, meaning that power is stored directly in the battery in its DC form. As the process of converting AC to DC incurs some proportion of energy loss, DC-coupling ensures that this is kept to a minimum as there is only one total conversion required. Maximising yields, minimising costs As the residential market continues to expand apace, it will be flexibility that will be the deciding factor for both homeowners and installers alike when it comes to their PV system. In a highly competitive marketplace, the task at hand for PV technology manufacturers is to continue innovating and investing to ensure that they can offer a solution that is suitable for all customer scenarios that maximises yields while minimising costs. www.solar.huawei.com68 PES Solar

A passion for environmental technologies. High-tech solutions for industrial waste gas and wastewater treatment. www.centrotherm-cs.de

TALKING POINTMonitoring the effects ofsoiling on photovoltaic cellsKipp & Zonen continue with their quest to improve the measure the effects of panel soiling onDustIQ, which can now be locally calibrated for the exact photovoltaic performance.dust composition on site. This means the PV panels can bemonitored 24/7 and cleaned whenever necessary. PES Advances in increasing solar celldelves deeper to bring you the latest on this affordable and efficiencycompact, cost saving, optical measuring tool. The world’s first photovoltaic device wasThe maximum efficiency exhibited by solar Primarily these are solar irradiance, created by Edmond Becquerel at the ripecells has been incrementally improved over temperature, and soiling. While the effects old age of 19, while conducting150 years of scientific endeavour. But while of solar irradiance and temperature are experiments in his father’s laboratory.1photovoltaic technology continues to well-understood, the detrimental effects of Edmond, the son of prolific electro-/improve, the amount of power we can soiling on solar panel performance often go bio-chemist Antoine Becquerel, found thatgenerate from solar cells is ultimately overlooked. However, new technologies are a platinum electric I think they meandictated by environmental factors. making it easier than ever before to conductor coated with a thin layer of silver chloride could be coaxed into exhibiting a phenomenon previously unknown to science: When placed in an electrolytic solution with another electrode and illuminated, a current started to flow.270 PES Solar

TALKING POINTHis experiments were meticulous. Having The front page of the New York Times the investors think twice before setting up aruled out thermoelectric effects and even next day proudly proclaimed that the ‘Vast solar cell arrays in desert climates.managing to obtain a rough spectral Power of the Sun is Tapped’, these cellsresponse curve by shadowing the electrode heralded the arrival of compact, efficient The effects of soiling are not to bewith a series of coloured filters, he correctly and commercially viable solar cells.6 Since underestimated. Soiling can lead to lossesdeduced the nature of the chemical then, the sustained efforts of generations of in energy production of over 10% perreaction that occurred at the photosensitive scientists and engineers have multiplied the week. Accumulated dust and grimeelectrode. Becquerel had created a efficiency of solar cells several times. As of negates a sizable chunk of each solarliquid-phase photoelectric cell, the December 2014, the world record for cell’s hard-earned capacity.8 Forprecursor to the familiar (and much more photovoltaic efficiency, the ratio of incident photovoltaic facility owners, balancing theconvenient) silicon cell which would go on solar radiative energy to usable electrical cost of cleaning cells with losses due toto become the fastest-growing renewable output, stands at an impressive 46%. soiling is critical. But unlike relativelyenergy source in the early 21st century.3 well-understood factors such as solar Environmental factors are the most irradiance and temperature, the effects ofPhotovoltaic cells have come a long way important soiling are difficult to predict. So, asince Becquerel’s experiment in 1839. In question arises: How can we accurately1876, scientist William Grylls Adams However, while the theoretical efficiency of gauge the effect of soiling on a givenshowed that photovoltaic current could be photovoltaic cells is painstakingly pushed photovoltaic system?generated without heat transfer or moving upward by scientific advances, their trueparts, laying the foundation for modern performance in situ is at the mercy of Instrument manufacturer Kipp & Zonen,photovoltaic cells.4 Over the next 50 or so environmental factors. have answered this question by developingyears, the photovoltaic effect (or ‘Becquerel DustIQ: a novel way to optically measureeffect’) was demonstrated in a number of Variations in solar irradiance are obviously a photovoltaic soiling. While other soiling-different materials, but efficiency did not primary concern. Slightly less obvious is measurement systems work by comparingbudge from around 1% until the 1950’s the effect of temperature on photovoltaic the signals from a clean cell and one that iswhen the power of silicon was discovered. efficiency: increasing the temperature allowed to accumulate dirt, requiring bothIn 1954, Bell Labs made headlines with the increases charge-carrier recombination sunlight and perpetual cleaning to work,first ‘practical’ silicon solar cell, with an rates, effectively taking electrons out of DustIQ measures soiling directly withoutefficiency of 6%.5 action in the cell, which reduces the the need for fortuitous weather conditions generated voltage.7 Unfortunately, both of or maintenance. 9 10 these factors are difficult to control. But there is one significant threat to The compact system is designed to be photovoltaic efficiency which we’re not mounted in between or to the side of an powerless to prevent: soiling. existing photovoltaic array. Using an internal LED and photodetector, DustIQ Measuring photovoltaic soiling in analyses the light reflected by the soiling. real-time Greater soiling results in a higher proportion of reflected light. With causes including but not limited to dust, plant products, soot, salt, and even The recently added small PV cell allows the bird droppings; soiling can be a serious DustIQ to be locally calibrated for the exact threat to the power production of dust composition on site. Using the local photovoltaic cells. Soiling due to dust is calibration the DustIQ calculates the exact particularly prevalent in the dry areas which soiling ratio, which can be translated into receive high sunshine levels – areas which power losses in real time. The local dust are otherwise most attractive for calibration and PV cell only only need to be photovoltaic installations – enough to make done once. www.pessolar.com 71

TALKING POINTThe DustIQ’s affordability and maintenance resources. DustIQ is accurate, simple-to- 3. Renewables 2017. Available at: https://free concept enables multiple units to be use and cost-effective; providing the www.iea.org/publications/integrated into a single system measuring information needed to keep photovoltaic renewables2017/. (Accessed: 28thlocal variations in soiling across larger installations working at their best. February 2018)photovoltaic plants.11 Thus offeringredundancy in measurements and insight www.kippzonen.com 4. R enewable and alternative energyinto the dust distribution over the plant. resources : a reference handbook. Smith, References and further reading Z. A. (Zachary A. & Taylor, K. D. (ABC-Armed with up-to-the-minute information CLIO, 2008).on soiling even in the dark, photovoltaic 1. Mémoire sur les effets électriquesplant operators can schedule cleaning of produits sous l’influence des rayons 5. APS Physics -This Month in Physicspanels in direct response to actual soiling solaires. E. Becquerel. Comptes Rendus History. (2009). Available at: http://www.rates, allowing them efficiently to prevent 561–567 (1839). aps.org/publications/apsnews/200904/significant energy loss and wasting physicshistory.cfm. (Accessed: 28thunnecessary expenditure on cleaning 2. B ecquerel photovoltaic effect in binary February 2018) compounds. Williams, R. J. Chem. Phys. 32, 1505–1514 (1960). 6. V ast power of the sun is tapped by battery using sand ingredient. Murray Hill, N. J. New York Times 1 (1954). 7. Temperature Dependent Photovoltaic (PV) Efficiency and Its Effect on PV Production in the World: A Review. Swapnil Dubey & Jatin Narotam Sarvaiya, B. S. Energy Procedia 311–321 (2013). 8. Energy yield loss caused by dust deposition on photovoltaic panels. Sayyah, A., Horenstein, M. N. & Mazumder, M. K. (2014). doi:10.1016/j. solener.2014.05.030 9. Kipp & Zonen - DustIQ. Available at: https://cdn2.hubspot.net/hubfs/2519616/ DustIQ - Presentation WFES 2018 - Abu Dhabi.pdf. (Accessed: 1st March 2018) 10. Kipp & Zonen - DustIQ for PV soiling monitoring. Available at: http://www. kippzonen.com/Product/419/DustIQ- Soiling-Monitoring-System. (Accessed: 1st March 2018) 11. D ustIQ the novel soiling monitoring solution for solar panels. Available at: https://info.kippzonen.com/dustiq. (Accessed: 1st March 2018)72 PES Solar



ASK THE EXPERTS microCELL TLS half cell cuttingLeading the way in preciselaser micromachiningPES met up with Frederick Bamberg, Product Manager at as doping. Those in the TFPV segment3D-Micromac AG in Chemnitz, Germany, to discover the prefer the microSTRUCT LS for thin filmsadvances in laser machines and processes in relation to the on glass panels as well as the microFLEXPV industry. Efficiency and cost savings are being achieved family for thin films on flexible substrates.through listening to the customer, R&D and expertise. Apart from these established massPES: Welcome back to PES Solar/PV establishing itself amongst the Top 3 production tools, we also offer fully flexiblemagazine. For the benefit of our new manufacturers of laser equipment in the platforms to R&D centres in the sector.readers would you like to begin by solar industry. Currently we are also working on anexplaining a little about the importance elaborate, fully customised tool, for aof the solar industry to 3D-Micromac? We offer different machine concepts for special PV pilot line. The customer benefits the various fields of the PV industry. For from this broad variety of expertise andFrederick Bamberg: The PV industry is example, our customers in the c-Si/wafer process know how.one of our key markets and accounts for based segment prefer our microCELL OTFapproximately 30% of our business. Within and microCELL TLS platforms for PES: We would like to know what makesin few years 3D-Micromac succeeded in PERC-LCO, innovative cell cutting as well your laser equipment stand out from the competition? FB: Our philosophy is completely different from our competitors. We grant the customer a much wider flexibility; our platforms match74 PES Solar

ASK THE EXPERTSDemo center at 3D-Micromac’s head quarter in Chemnitz, Germany, with automated laser tools of the micro- Kept simple: interior of PERC-LCO laser tool withCELL family for PERC ablation, doping and half-cell cutting contactless continuous motion wafer transportprecisely the specific needs. One particle, on one chuck, damages every cell cutting process means an increase in eighth cell that later on breaks in one of the mechanical strength of modules.Also they are far from being just a rebuild or three printing steps. Questionable toolsimplified version of existing tool concepts, design of the laser equipment is hidden in PES: Is this the Thermal Laseras is often the case. the relatively high yield loss seen in the Separation (TLS)? You won the metallisation step. Megawatt Prize for Outstanding HalfWhen designing the microCELL concept we Cell Cutting Technology at SNEC 2016,looked at the disadvantages of current When using the microCELL OTF platform, what has happened since then?systems on the market and gathered the wafer is hovered onto an air film throughfeedback from production engineers and the machine, so no active force is applied FB: Yes we did. Cleaving by thermal stressoperators about their most important but, which could cause damage. The other rather laser ablation and breaking withto date, unmet expectations. So with this benefit of throughput increase becomes force. The technology attracted atool concept, the customer benefits from a obvious if a customer aims for dense LCO tremendous interest in the industry. As youbasically contact less wafer transportation, patter and/or expansion volume in the GW would expect, clients wanted to sample theas well as processing in continuous motion. range, by avoiding stand by times for the technology on their own material to confirmThe benefits are obvious: scratches and laser source for the movement cycles. You the advantages.micro cracks are avoided while the simply need one tool less meaning lowerthroughput is boosted by ~20%. operator costs, foot print, and depreciation. TLS machines went to R&D institutes and together with industrialisation partners wePES: Could you please explain in more PES: Interesting! Do you see such topics successfully transferred this technology todetail how these unique features create like quality and throughput currently mass production. The initial microCELLa benefit in mass production? Are these attracting more attention in the solar TLS machine got an update, whichof value to all cell manufacturers? industry? became the new standard, based on all lessons learned from the experience ofFB: Well, at least to the ones care about FB: For sure. Despite the impressive dozens of millions of cells.quality and yield in their production. Those growth rates of the end customer marketcustomers that would rather look at the and its matching expansion on the solar It’s an honour that competitors started tocost of ownership at mid-term than initial cells and module production capacity, the look for a work around our patent portfolioinvestment only. I am always surprised at end customers are not forced to buy and started similar research. Inhow often engineers in charge, have got a anything available. comparison tests we are still able to seelimited awareness of the damage grippers, the lead our process has against thesepickers and vacuum chucks cause to their Competition is strong, so on one hand cell trials, but it underlines that the formercells at the laser step. makers are aiming to improve their step standard process of laser ablation is at the costs by increasing the yield, on the other end of its life cycle. Again, at least forMaybe this is because after the LCO step hand, banks and project developers quality concerned companies.comes the screen printing. People might see carefully look at the quality of the solarthe printer/the print nest as the root cause of panels. There have been too many cases of PES: What are the main advantages ofincreased breakage rates, although severe power losses in solar parks and these types of machines in comparisonhundreds and thousands of cells simply failing modules. The financial plan is based to others – are they durable, costbreak under the squeegee pressure because on an operation over 20 years or more at a effective, more efficient etc?the previous laser machine created defined power degradation over that timeunnoticed micro cracks. The problem is span. Anything that helps reduce the loss of FB: Compared to today’s standard processeven harder to detect if you think of using an generated power over time represents of laser ablation, the main benefit is theeight nests rotary table in your laser. value. Similarly our innovative and patented approximately 30% higher mechanical strength of the half cell. Basically the force www.pessolar.com 75

ASK THE EXPERTSTLS cut half-cells achieving more than 1 watt additional module power compared to conventional scribe and After the boost in module power bybreak methods converting Al-BSF (Aluminium Back Surface Field) technology based productionremains the same on half cells cut by TLS, The current automation achieves values lines to PERC (Passivated Emitter and Rearas it was on the original full cell. However, well above 10,000 half cells per hour. So the Contact) on the cell side, this is thethe breakage force value decreases benefit is that one tool replaces three to corresponding technology change at thedrastically when cutting a cell by scribe and four of the competition. Apart from that, module level.break, caused by micro cracks introduced keep in mind, the process does not createwhen actively breaking the remaining part huge amounts of dust, as in the former Whereas for PERC technology one had toof the laser grooved cell. process. All those frequent filter changes, invest in a passivation layer deposition tool downtime for cleaning cycles, health and and a laser for opening it locally, convertingBy using 3D-Micromac’s TLS process, safety considerations means that Thermal to half cell modules requires cutting lasersmodule manufacturers are able to guarantee Laser Separation is setting the new and additional stringers. Implementation isa lower power degradation value over the standard in cell cutting! straight forward because the existingtime a module is operational. On the other production lines are supplemented and nothand the nominal module power starts at a PES: And would you say, there is a trend replaced. And module power is key forhigher level. In addition to the 5-7W gained in the industry to go to such module reducing the costs per Watt peak. Going toby the half cell design, due to reduced designs with half cells? half cells is a manageable investment with amodule current, we found an average of return in typically less than a year.approximately another 1W in a 60 cell FB: Definitely! Wouldn’t you? It’s not just likemodule, as on each cell the electrical losses this, that at each trade show most PES: And looking to the future?at the cut surface is reduced. manufacturers display such modules. It’s really something you can buy in high volume FB: I think the whole community can beFurthermore, there is a smaller surface due already. And the market share in increasing. proud off having brought solar energy toto the smooth appearance of the this milestone level of 100GW productionhomogeneous split crystal, as well as the About 3D-Micromac capacity and its financial competitivenesslack of defects in molten and then against other sources of energy generation.recrystallised material in the ablation zone. 3D-Micromac, with headquarter inAs the heat level is much lower, this is Chemnitz, Germany, is the leading The market conditions, technology,specifically another benefit for heat specialist in precise laser geographically, politically, financially, etcsensitive cell concepts like hetero junction micromachining. Target markets are still changing fast and the door is open:technology. The gains multiply, if you think include the photovoltaic, you are more than welcome to join in.of smaller stripes than half cells, as the semiconductor, glass and displayamount of defects per cell volume industries, as well as micro diagnostics I’d like to give my profound thanks to all ourrepresents a higher share, the smaller the and medical technology. customers and partners worldwide for theirpieces of a solar cell are. trust in 3D-Micromac and their belief in the There is worldwide network of technology changes. Whether it is inPES: Please could you also tell us about distributors guaranteeing service and innovative wafer transportation or a newlythe tool concept? What does a module close contact with the customers. developed cutting process.manufacturer can expect there? A strong in-house R&D division Remember for any laser solution, standardFB: The microCELL TLS uses a high speed provides innovative processes and or customised, wafer based or on sheets assplitting process without the need to have a machine concepts which means well as foils, do not hesitate to contact us.slow scan speed, or multiple passes, as 3D-Micromac is able to offer uniqueseen in laser ablation. At 300 to 500 mm/s solutions to its customers. Frederick Bamberg studied MEMS atyou end up with being limited by the ability Albert Ludwigs University Freiburg andof the handling automation to load a www.3d-micromac.com obtained his degree in 2004.maximum number of cells onto our singlelane tool. And unload twice the amount of www.lasers-for-photovoltaics.com From 2000 until 2006 he worked inhalf cells. different research groups at Fraunhofer Institute for Solar Energy Systems (ISE) in Freiburg, Germany, BP Solar in Sunbury, U.K. and the University of New South Wales (UNSW) in Sydney, Australia, before working as process engineer at Solarworld in Freiberg, Germany, from 2007 to 2015. In 2016 he joined 3D-Micromac AG in Chemnitz, Germany, as product manager. He is in charge of PV industry related laser machines and processes.76 PES Solar

PPowVeTreschtnheolWogoyrldINNOVATIVE TECHNOLOGY Come & see us atFOR PHOTOVOLTAICS IntersolarWith our production equipment we improve cell efficiency and reduce Europe 2018manufacturing costs. Take a closer look at these production machinesfor thin-film solar cells (CIGS, CdTe, Perovskite) and high-performance Booth No. A2 / 360crystalline solar cells (PERC, HJT, IBC, HBC, TOPCon):→ Advanced vacuum thin-film coating (sputtering, evaporation, PECVD)→ Wet chemical processes→ Thermal processing (selenization, sulphurization)→ Combination of thin-film and wafer technologies for the fabrication of Perovskite based top cells in crystalline tandem solar cellsSINGULUS TECHNOLOGIES | tel: +49-6188-4400 | [email protected] | www.singulus.de

TALKING POINTTesvolt Battery Storage SystemNew opportunities: why theUK market for battery storagesystems is relevant to usWords: Lawrie Wilson, Area Manager UK & Ireland at Tesvolt The battery market has gained added momentum. There is now a global awareness that renewable energies can only be successfully expanded in combination with efficient energy storage. The greatest efficiency – and profit margin – is currently offered by battery storage systems, as this technology is already extremely advanced. Lawrie Wilson At Tesvolt we specialise in high-performance growing worldwide, at the same rate as the Lithium-Ion storage systems for use in expansion of renewable energies,78 PES Solar industry and commerce. Lithium batteries especially photovoltaic energy. While yields are safe and especially low maintenance, from renewable energy sources fluctuate and can store electricity and supply it again over the course of a day and a year, for extremely quickly. We have a wide range of example because a PV installation does not products with storage systems for every absorb solar energy overnight or during application, offering capacities from 4.8 kWh winter, a storage system can balance to several Megawatt-hours. supply and consumption. Countless applications A battery can keep the energy stored during the day for times when demand is The need for battery storage systems is

TALKING POINTTesvolt Lithium storage system TS for commercial use with us than with the competition. We achieve this by using high-qualityhigher, thus helping the user to increase providing battery storage as a service can components. For example, we sourcetheir self-consumption and save costs, or offer users profitable deals. exceptionally safe and efficient battery cellsbecome less dependent on energy from the Korean manufacturer Samsung SDI.companies. But this is far from the only Another aspect that makes the UK marketpossible use; battery storage systems are especially interesting is the constantly rising Our proprietary Active Battery Optimiserextremely versatile. As well as using time cost of electricity. This is making energy (ABO) ensures that battery cells are alwaysshifting to increase self-consumption from efficiency more and more important. optimally charged and discharged. UnlikePV installations, they can also help to keep Electricity prices have continued to rise over conventional passive or unidirectionalpower consumption constant and avoid the last year, which could create a location battery management systems, the ABO notexpensive peak loads via peak shaving. problem for large consumers in particular. only optimises all the cells within a battery module, but also the individual batteryOther possibilities include use in back-up A battery storage system makes it possible modules in relation to one another.power solutions and stand-alone grids. to cut electricity costs via time shifting, theHere in the UK, our energy storage systems battery system can store the electricity The ABO monitors the temperature, voltagehave become a valuable option to avoid produced by the user’s own PV installation, and state of charge of each individual cell orTriad, Red Zone, or CM levies. for example, and then supply it as needed. module and controls them within the battery This is especially attractive for businesses, system. This process significantly increasesThese capacities make battery storage which consume power outside of the the service life of individual cells. With up tosystems well suited to applications around middle of the day, when the PV installation 8,000 charge cycles, our storage systemsthe world – both in developed industrial produces the most electricity. have a service life of approximately 30 years.nations and far from public grids, forexample in the mountains or the desert. We’re also seeing that larger energy The service life is a crucial factor in costAnd in the last year, the UK in particular has customers remain concerned about how efficiency, as are the system’s dimensions.seen developments that make this an reliably they can draw their energy from The number of full cycles is equallyespecially exciting market for us. international sources. Against this important, to ensure that the system can background, it’s easy to see why energy perform for as long as possible. LowAttractive prospects in the UK companies are currently trying to spread maintenance costs and high efficiency are their portfolios across different generating also key to a fast return on investment.For example, we’ve noticed that companies installations. This goes some way towards Finally, with an eye to investment protection,have increasingly been offering ‘battery reducing the risk created by dependence it’s important to take into consideration thestorage as a service’ since last year. This on a single supplier. possibility of expanding the storage systemallows the end customer to pay a fee for a few years down the line and of replacingenergy storage without owning the Battery storage systems are increasingly battery modules individually.equipment. It’s creating an added incentive becoming part of this mix, as they can befor the battery industry to produce highly used almost anywhere, can quickly store UK businesses are slowly catching up withefficient systems which offer a low LCOS. and then supply large quantities of energy the industry leaders on the Continent inThe abbreviation LCOS stands for levelised and combine exceptional performance with terms of experience in the use of batterycost of storage, which refers to the costs of a small footprint. We also see significant storage systems. The key factors here, in ourstoring one kilowatt hour in a battery potential here, as storage systems have view, are efficiency and better productionstorage system including battery inverter – become yet more efficient and are thus an planning based on consumers’ needs.without taking into account production increasingly attractive investment for largecosts, which are included in the LCOE suppliers such as municipal utilities. Thanks to the new opportunities they(levelised cost of energy). create, including through the switch to Lower LCOS means high profit margins half-hour measurement intervals, batteryBattery storage systems with a particularly storage systems are being usedlow LCOS maximise throughput while The unique feature of our battery storage increasingly often for peak shaving andreducing costs, so that system owners systems is a particularly low LCOS, which time shifting, however, the purchase price means the investment pays off more quickly remains an obstacle when it’s looked at in terms of CAPEX rather than OPEX. We need to keep working on developing and publicising the most cost-effective applications for our storage systems. www.tesvolt.com TESVOLT Founded in 2014 Founders: Daniel Hannemann and Simon Schandert Number of employees: 50 Location: Lutherstadt, Wittenberg, Germany Technology - nickel manganese cobalt oxide cells Product focus - industrial and commercial Capacity range - up to several megawatts Intersolar/EES booth: B 1.550 www.pessolar.com 79

TALKING POINTPump down curves andtheir information valuePfeiffer Vacuum are specialists in vacuum technology. They In Figure 2, the effect of a flexibleprovide the highest quality testing in order to provide top class corrugated hose on the pump down behavior can be seen. It is used as aproducts. Here we learn about the importance of the pump connection between the chamber and thedown curves and the different materials that can affect them. pump. The tube has a length of 1000 mm and a diameter of 40 mm. Pump down curve oThfeaco1nn0e0ct-inligteberllocwhsahamvebalemrost no used as a vacuum pumpw. Tihtishcuarvreosetraversy vaefnfeect opnupmumpp dDowunotim6e5above aDisplaying and interpreting processes in icatosisnthnaeescsstut11eam100dn1000edt00d00oarttdhhaefotPcrthhucaeommmpbupwpemar.rpidistioshondw.airInencrFtoilgyctuuarerr1vy, evoatpworfnae0nsae.t0st1uo1prhef0uPuora0mft,ha-telphpripeterepvoDauxrcmiumucpoaahttdeeao6ltywhm51en hcpbPhroeaacm.reBbsuestrwidfiowllwenPressure P[rhePsas]ure [hPa]different vacuum ranges 1010Pump down curves are a popular controlinstrument when designing and operating 01.01a vacuum system. Thanks to them, anyproblems in the system can be derived 0.011and the correct pump performance canbe assessed. 0.000.11 0.5 1 1.5 2 2.5 3 3.5 0 Pump down curves, ideal Time [min]A pump down curve describes a time-dependent pressure drop in a vacuum 0.01system. In a graphical representation, the 0.001time is applied to the X-axis and thepressure to the Y-axis. For the known 0 0.5 1 1.5 2 2.5 3 3.5geometry of the vacuum chamber andpumps, a pump down curve can be Pump down curves, ideal Time [min]calculated. Any deviations between thecalculated and the measured pump down Figure 1: Pump down curve of a 100-liter chamber with a rotary vane pump Duo 65curve will often provide information aboutproblems in the vacuum system. This also Conductance Effectapplies to the comparison of curvesmeasured over long-term use with areference curve.Pump curves in in the low vacuum Pressure P[rhePsas]ure [hPa] 1000 Conductance Effect 3 3.5range: displaying connections, Time [min]interpreting, and applying 100 0.5 1 1.5 2 2.5 Pump down curves, ideal 3 3.5A reference curve can be measured when 10 Pum0.p5 down 1curves w1i.t5h condu2ctance 2.5 Time [min]the system runs properly and without any 10010problems after startup. Under theseconditions, the pressure drop is measured 100.10over time during pump down. The 0.1001measurement can either be taken manually, 0.0011using a system control, or using thesoftware packages for pressure gauges 0.1 0provided by Pfeiffer Vacuum. 0.01In the example in Figure 1, the calculated 0.001pump down curve of a 100-liter chamber isdisplayed. A Duo 65 rotary vane pump was 0 Figure 2: Conductance ePfufemct p down curves, ideal80 PES Solar Pump down curves with conductance

TALKING POINTPressure [hPa] Influence of water or from installations. This value may change depending on the vapor pressure of the 1000 medium or the accessibility of the surface. 100 10 • Influence of alcohol 1 If the vacuum system is cleaned with a highly volatile alcohol, such as isopropanol, 0.1 the alcohol will evaporate quickly. 0.01 Evaporation takes place more quickly than the pump down and no bend in the pump 0.001 down curve is observed as in the water 0 2 4 6 8 10 entry in Figure 3. Pump down curves, ideal Time [min] • Influence of oils or operating fluids Pump down curves with conductance Pump down curves with water vapor Oils and operating fluids from backing pumps may indeed have a significant impact on and create a hump in the pumpFigure 3: Influence of water on the pump down process down curve with a lower pressure than in the given example. This also applies to water vapor desorption, which does nottake about 20% longer, solely due to the a slow desorption of the water film come from a free surface but, for example,effect of the bellows. A solution for this is to adhering to the inner surfaces of the from a winding.shorten the connection piece or to increase vacuum chamber. This particular surface of• Iiwnnsflauulteaenticroenof films for thermalthe piping diameter. process is significantly slowerInthfalnutehence paluremapdyd1oin0w0tnh0eofgaasgeaosuosr a vapor, which is Figure 5 shows the effect of usingFlow resistance depends linearly on the phase. thermal insulation in the interior oflength, but in the third or fourth power on vacuum chamber.tshheoudlidambeetienrc. rIefPainsuedmdouabpst,atdchoeordrweiacmntiveetceur rvePressure [hPa] a film for Pressure [hPa] the wcFiutighruvreeain31ts1hh010eo00rwcasnmgthee2bbeientwnsdeeuonflta1h0teaiponudnm1phdPoaw, nbcmoeentawnseeuecrn1teio0trhna0.et0hItnewrtohthicsauncravsseheso,rstthheeofnowicnsoiglmtthhipenearitshone vaclwauyheiucrhmoins atcysph1uicrafaalmcfeorboafetwhraetevar cvuaupmor adsorbed The desorbing medium is actually water chamber vapor, but due to the stronger bond to theinfluence1o0f0the pipe and can help with 0.1designing1th0e connection between the 0.01chamber an1d the pump. 0.001Pump do0w.1n curves display different 0246 8 10influenc0e.s01 Time [min] Pump down curves, idealThe op0e.r0at0io1n of the vacuum system can be Pump down curves with conductanceinfluenced dra0stically by diffe2rent factors: 4 6 Pump do8wn curves wi1th0 water vapor• Influence of watePrump down curves, ideal Time [min]Figure 3 shows the iPnuflumepncdeoowf anscmuarlvl es with conductanceamount of water onPthuemppumdpowdonwcnuprrvoecsesws:ith water vaporThe previously achiePvuemd bpadseowprnescsuurreveiss with insulation foilmissed by more than a factor of 100 and thetime scale seems to be almost infinitelyextended. This example of a curve has beenmeasured in an existing coating system.Over time, both the parts and the carriershave been coated. Coating of the parts is a Figure 4: Oil and Popuermatinpg fludidos fwromnbacckuinrgvpeumpws mitahy haave1a0sigcnimfican2t iimnpsacut olnaptuimopndown curveswell-controlled process in order to achieve a foil in the vacuum chamberdense layer with high adhesion and tailoredtribological properties. However, coating of Pressure [hPa] 1000the carriers is a random process which leads 100to a coating with a loose, brittle multi-layer 10structure with low adhesion. The loose, 1layered structure tends to release particles 0.1and form a large surface area. On thissurface area, which has built up over time, 0.01large amounts of water vapor can now 0.001 24 6 8 10accumulate and these thin absorbent layers 0 Pump down curves, ideal Time [min]cannot be detected with the naked eye. Thetime required for the pump down has not Pump down curves with conductancesuddenly become longer but has beenslipping over an extended period of time Pump down curves with water vaporduring operation. Pump down curves with insulation foilThe first step of pumping down water Figure 5: Pump down curve with a 10 cm2 insulation foil in the vacuum chambervapor from vacuum chambers consists of www.pessolar.com 81

TALKING POINT Pump down curves Pressure [mbar] 1.0E+02 1.0E+00 1.0E-02surface and the slow escape from the foil 1.0E-04 20 40 60 80 100 120winding, the water signal only appears at a Time [min]lower pressure. In the given example, the 1.0E-06 Pump down curve with stainless steel surfaceaddition of just 10 cm2 of foil insulation Pump down curve with acrylic glass doorleads to an extension of the pump down 1.0E-08 Stainless steel, tablestime up to a base pressure of 75%. In 0 Acrylic door, tablesaddition to insulation foils, cable sheathingor other plastics in the vacuum can display Figure 6: Pump down curve of a vessel with 500 mm edge length; pumping system: backing pump andsimilar effects. HiPace 300 turbopump• P ump down curves in the high Differences between stainless steel therefore recommend scaling, or even vacuum range and acryl selecting new pumps, on the basis of the measured data. This means that weEven if vacuum is defined as empty space, With a stainless steel door, the processes recommend plotting a reference curve init does not mean that there are no gases at inside the chamber cannot be observed. both the low vacuum and high vacuum range.all left in high vacuum systems. Also at low However, replacing a stainless steel doorpressures, water vapor can greatly affect with a transparent acrylic glass door As a rule of thumb, it can be said that thethe achievable base pressure of a system. changes the material and the surface of the outgassing rate of metals is relatively lowWater may outgas from the surfaces of the door and also affects the desorption gas while plastics provide much highervacuum chamber. The outgassing rate flow. In tables, the desorption rate per unit contributions to the total gas flow. Exceptionsdepends to a great extent on the surface area of acrylic glass is given as around to this rule are found in metals such as zincmaterials, such as metal, glass or plastics. 300 · 10-9 mbar·l·s-1·cm-2. or brass alloys, which also exhibit very highIn addition to the material, the quality of the outgassing rates. The outgassing rates ofsurface can also have a major influence on This means that if we replace 1/6 of the elastomers can be affected by the chemicalthe outgassing rate. stainless steel surface with the acrylic door, composition and additives. Mechanical or we get a desorption gas flow totaling 7.66 · thermal pre-treatment can drastically reduce• Influence of different materials in the 10-4 mbar·l·s-1 and thus a base pressure of the outgassing rate. So it pays to invest in high vacuum range 2.55 · 10-6 mbar. Essentially, the observation vacuum compatible materials. facility through the transparent door isAs an example, the standard KBH type achieved at the cost of attaining a higher Before choosing a pump: analyzingcubical chamber from Pfeiffer Vacuum is base pressure, reduced thermal stability of pump down curvesregarded. The medium-sized chamber has the materials, and reduced bakeability.an edge length of 500 mm. In cubic Before investing in new pumps or vacuumgeometry, this corresponds to a surface of Figure 5 shows a comparison of the pump chambers, analyzing a pump down curve15,000 cm2. On this surface, a supply of gas down curves of an identical chamber with a should be obligatory. Deviations between ais adsorbed which is slowly released from stainless steel door and an acrylic glass reference pump down curve and athe surface. This outgassing takes place door. In addition to the data points which measured curve often allow faults to bemuch slower than the pumping down of gas every user can calculate manually from detected at a glance. Detailed analysis of athat is freely present in the room. Data for the publicly available tables after an hour, pump down curve allows for a betteroutgassing rate from surfaces can be found complete pump down curves with a understanding of the processes involvedin tables attached to vacuum textbooks. commercially available simulation program and offers approaches to problem solving. are also shown.For the chamber material (stainless steel When moisture enters into the system, an1.4301 or SS 304), an outgassing rate per Plotting a reference curve in low as well external drying of the used components orunit area of approximately as in high vacuum the cleaning of the vacuum chamber is often1.3 · 10-9 mbar·l·s-1·cm-2 is specified. This better in achieving the target values for therather unwieldy unit gives a gas flow in Depending on the origin of the data in the down pump time than investing in largermbar·l·s-1 in relation to a surface area in cm-2. tables, it is sometimes possible to achieve a pumps. In particular, the surface treatment good correlation. However, in the literature, a of the chamber in the high vacuum is one ofIf the value of the outgassing rate per unit span of more than three decades is given for the most important parameters for thearea is multiplied by the surface area of our stainless steel. The large variation is due to achievable ultimate pressure.chamber, this results in an outgassing rate different alloys, pre-treatments, surfaceof 1.95 · 10-5 mbar·l·s-1. If we evacuate the finishing, and baking out. With its broad product portfolio, Pfeifferchamber with a HiPace 300 type Vacuum offers the optimal solution forturbopump with a pumping speed of From our model with the acrylic glass door, various vacuum ranges and applications.300 l/s, we theoretically obtain a base we can immediately see significant deviationspressure of 6.5 · 10-8 mbar. The data from figures given in the literature. We would www.pfeiffer-vacuum.comprovided in tables are usually measuredafter a pumping time of one hour. Wetherefore need an hour to reach thespecified pressure. The outgassing rate canbe reduced by pumping or baking out thevessel for a prolonged period.82 PES Solar

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ASK THE EXPERTSBankability and quality Olivier Haldi, Global Business Development Photovoltaics and Alternative Energies, met up with PES to share the reason behind the recent rebranding from Multi-Contact to Stäubli Electrical Connectors and the importance of using high-quality components.Olivier Haldi Stäubli is a multi-national group The first industrial photovoltaic connector headquartered in Pfäffikon, Switzerland. (MC3) was introduced by Stäubli in 1996PES: Welcome back to PES Solar/PV We are a global mechatronics solution followed by the original MC4 in 2002 settingmagazine. Thanks for talking with us. provider with three dedicated activities: the industry standard ever since. TheFor the benefit of our newer readers, fluid and electrical connectors, robotics, exclusive MULTILAM advanced contactwould you like to begin by explaining a which are also used in PV panel production technology raised the bar in terms oflittle about the background of Stäubli lines and textiles. We serve customers who consistent quality and outstandingand the importance of the Solar/PV want to increase their productivity in many dependability. We never compromise whenindustry to you? industrial sectors. it comes to quality, long-term reliability or our partners’ success.Olivier Haldi: Originally founded in 1892 as We are an international group that currentlya small workshop in Horgen/Zurich, today operates in 29 countries, with agents in 50 Today, we have more than 200 GW of countries on four continents. Our global installed photovoltaic capacity, amounting to workforce of 5000 shares a commitment to nearly 50% of the global cumulative PV partnering with customers in nearly every capacity that had been successfully industry to provide comprehensive connected using our Stäubli photovoltaic solutions with longterm support. connectors. This figure demonstrates the reliability and highest quality of our products. Stäubli Electrical Connectors, formerly They guarantee proper operation over their Multi-Contact, was founded in 1962 and is whole lifetime, >25 years, defy harsh part of the Swiss Stäubli family. We have over environmental influences and have a positive 55 years of practical experience in producing impact on the bankability of photovoltaic reliable electrical connectors for different projects. Our position on the global market is industries. We have been the pioneer and the result of our continuous efforts to meet market leader for electrical connectors in and exceed our customers’ demands. photovoltaics for more than 20 years.84 PES Solar

ASK THE EXPERTSCalculation of the economic impact: Solar Bankability is a project funded by the European Commission’s quoting aggressively low prices, particularlyHorizon 2020 program (www.solarbankability.org). According to their ‘Cost Priority Number’ (cost-based failure across growing solar regions such as India,mode and effects analysis) of the top 20 technical failures in PV systems, cables and connectors can have a Latin America and MENA. Record-lowhuge financial impact (€/kWp/year loss due to the failure). PPAs squeezing profitability and under this tough financial climate, the question is, ifPES: What was behind the rebranding of customer-specific solutions to an even there is a mismatch between what solaryour connectors from Multi-Contact to greater degree. We will now offer the entire owners and investors want, and whatStäubli Electrical Connectors? How has spectrum of highly reliable connection diligent EPCs can realistically deliver.this been received thus far? technology, which in such a manner is unique on the world market, under the How to maintain quality, profitability andOH: Multi-Contact has been part of the Stäubli brand. reliability in the grip of such financialStäubli Group for more than 15 years and squeeze? We have to be cautious, the runbecame Stäubli Electrical Connectors as of By taking over the name and brand identity for even lower prices can be dangerous;January 2017. The Multi-Contact logo has of the Stäubli Group, we ensure access to you get what you pay for. So we have to bealways featured a reference to the Stäubli expanded research and development competitive without compromising qualityGroup. To ensure that Stäubli Electrical resources in the long term and thus ensure and this remains our highest priority.Connectors will be henceforth recognised the innovative strength needed to developas the former Multi-Contact, the transition convincing, future-oriented solutions for PES: We are interested in hearing moreis accompanied by a co-branding customer requirements in the future. about your concept of bankability;communication phase. The two companies please could you explain what thisare united by shared values such as quality PES: Are you still experiencing growth in means to Stäubli?and innovation, strong customer this market?orientation and production designed to OH: The demand for safe, clean reliableoptimally meet the needs of the market. OH: At the moment, we are growing with renewable power is growing at an everThese are both driving force and basic the market in different regions. The outlook increasing rate. Today, PV technology is notprecondition for an even more impressive is promising, PV will become the major only ecologically, but also economically ainternational market activity. source for energy generation. We have sensible alternative for power generation. been increasing our production capacities With troubles on the financial markets andTaking on the Stäubli brand underlines our and will do additional investments to cover photovoltaics’ advancing independencebelonging to this innovative group. We are the market demand. from governmental subsidies, financing ofconvinced that this step will help us PV projects has become a relevant topic.establish a more effective presence on the Maintaining the economic growth at themarket. Together, we can advance the same time is challenging. The race for We have seen the increasing potential, butdevelopment of cutting-edge products and low-cost solar shows no sign of halting, investors only choose the most trustworthy with developers and IPPs increasingly and bankable projects. Generally speaking, in the solar industry, bankability is a term used to describe the degree of financial risk. The degree of bankability of any project, solution, technology or supplier will affect the availability and cost of capital. Bankability is a multi-dimensional construct and is perceived differently among stakeholders. There is no standard for bankability; each bank may have its own definition of bankability. In order to assess the investment risk of a PV project, technical, economical and legal aspects need to be evaluated. The quantitative economic evaluation focusses on the balance between total initial costs, total operating costs and levelised cost of energy. Stakeholders are assessed regarding their bankability in order to improve chances of a positive financial decision and to manage the associated technical risk. It is mandatory to work with bankable/solid partners and Stäubli with its background, track record, experience, financial strength, deliverables in products and services, is the bankable partner for cabling and connectors in the PV industry. At the same time careful selection, this means a lot more than just checking the data sheet and the certificates, of bankable products and components to be built into the system, is also a core topic, as these have considerable impact on the bankability and the economic success of a PV asset. www.pessolar.com 85

ASK THE EXPERTSToday, 200 GW PV capacity relies on more than 1.5 billion original MC4 connectors globally.The guiding principle for bankability is to influence of connectors on the long term by using cheaper components, is justifiedminimise risk while maximising the return. efficiency of a PV system? when considering the additional safety risksThis can only be achieved through secured during operation and decreased efficiencyefficiency in the long term on the basis of OH: As mentioned, third party studies show or return on investment in the long-termhigh-quality components. Wrong choices in that cabling/connectors can have a huge such a choice might bring.planning, due to lack of knowledge or low impact on the yield of a PV plant, too. Thequality components, can cause unexpected arising questions are now: What is the root When we break this down on the LCOE weloss of production or potential safety issues cause of these issues? Why can connectors know today, it is all about balancing CAPEXduring the lifecycle of a PV system. have such an impact on the overall yield and OPEX and an optimised energy yield. Of and is there an economically feasible way course the involved project stakeholdersLess attention is being paid by buyers and to reduce the associated risk? might have a slightly different view regardingespecially owners and investors to solar their respective intentions. So in order tobalance of systems (BOS) components and Basically, connectors are used in PV systems lower the CAPEX, one may try to lower alsotheir quality. Maybe the majority would not and in solar parks to ensure constant the asset costs of cabling and chooseexpect that, but results of third party transmission of the generated power from low-quality products or cheap workmanship.studies as well as our own experiences the modules by connecting them to strings,show that cabling/connectors have a major combiner boxes and inverters. Connectors But as already shown, we can clearly sayinfluence on the efficiency, the return on are therefore used in large numbers: for that the potential for optimising CAPEX byinvestment and, at the end of the day, on instance, in a 20 MW solar park, around using low-quality connectors/cabling isthe LCOE of a PV system. Small 140,000 connectors are installed. very low. At the same time, failures of thesecomponents, but big impact. small components can have a significantly The key to efficient operation and energy negative impact on OPEX as well as on thePES: Bankability appears to run through feed-in is long-term reliability and a energy yield. To mitigate these risks/failureseverything, does this include training? constantly low contact resistance. Vice versa and maximise the return in the long term, an increasing contact resistance inside the we really recommend paying attention toOH: Absolutely, through everything – the connectors will induce higher temperatures cabling/connectors of a PV system andcompany, people, products and services. and power loss, which will have negative mainly to the quality of the products, not toSo the main goal is to create awareness impact on the contact resistance again, thus neglect the quality of the installation andthat in a quite complex PV system details creating a spiral resulting in a high risk of handling as well.and also small components, such as partial connector failure. So theconnectors or cabling, really matter, consequences caused by these failures lead PES: Is this something that you believeraising the issue of quality. In the end, it is to power loss due to downtime, expenditure can help further strengthen Stäubli’snot only about the quality, but also about on service hours, costs for spare parts and position in the International or Chinesethe correct handling and installation of reconstruction measures and in a worst case PV market?these components. scenario to legal costs – altogether: higher operation/maintenance costs (OPEX) and OH: We have experienced many casesTherefore, you have to make the right lower energy yield. where wrong decisions on products and theirdecisions during the planning, construction handling have been taken. Quality issuesand operation period of a PV system to In this context and with having the focus on with PV systems can affect the wholemitigate the risks. We have to stress the the components and not on the handling, it industry or even the technology in a negativefact that their impact on the efficiency and is interesting to note that components for way, and can lead to doubts on the long-runthe economic success can be huge and cabling comprise only around 1%, for reliability in the investor community.that they are absolutely systematically connectors only 0.003%, of the overall totalrelevant. That is why we started to ramp up initial cost (CAPEX) of a PV system and You cannot manage the unknown; we havetrainings through our global team for the price savings among component choices to educate and share knowledge. We aredifferent stakeholders in the PV industry. rarely amount to more than 30%. Therefore, still a young industry and we have to work it is really appropriate to ask if a saving of together, upstream and downstreamPES: Please can you expand on the only 0.001% of the total initial cost, gained players, with the goal of making PV become86 PES Solar

Inverter ASK THE EXPERTS Battery Grid Load Power Higher Increasing High risk for (partial) connector failuresContact resistance temperature contact Performance losses, higher PPM-rates and & power loss downtimes of modules, strings or plants resistance Higher Higher High service/maintenance and spare part contact temperature costs for repairing resistance & power loss Hotspots and fire in PV system and reconstruction costs High costs for legal disputes due to undefined liabilitiesCabling of PV systems - constantly low contact resistance ensures long-term reliability and efficiency of aPV system. Low quality of components and/or incorrect handling/installation leads to increasing contactresistance, failures and extensive consequences.an even more competitive, but also PES: What is the single biggest Olivier Haldisustainable industry. So it is all about LCOE challenge facing the market today? Global Business Developmentand the long-term view. Photovoltaics and Alternative Energies OH: We have already broached this topic:All of us across the value chain have to do from our perspective, it is about delivering a Olivier has been with the Swiss-homework to mitigate and minimise risks in stable high -quality product in times of high headquartered Stäubli ElectricalPV systems. Some more mature markets pressure on prices and margins from the Connectors, formerly known aslearned their lesson, but there is still a lot market, but simultaneous increasing costs Multi-Contact, for more than threepotential for improvement, to an even for raw material and investment in new years. In his current function as Globalgreater extent in the more price sensitive production capacities to cover the greater Business Development Managermarkets like China. But we see more and demand of the market. This is a big Photovoltaics and Alternative Energies,more of a development that sets value on challenge and you have to find the right he is responsible for global keyquality and shares the conviction that balance. Quality is of utmost concern and account management, leadingquality pays off. Quality saves! you can see through all our activities: we do strategic projects and coordinating not play with it. In future, Stäubli wants to activities in subsidiaries. Before joiningOf course we want to strengthen our expand its position on the global market Stäubli, Olivier studied economics inposition in the market as this has to be a and, frankly speaking, we believe that this Basel, Switzerland and has gainedgiven goal for every company. With our goal can only be reached by pursuing a over 12 years of professionalapproach to quality/bankability we help quality approach. experience in marketing and sales inincrease the quality of PV installations the medical technology industry.worldwide and yes, at the same time we www.staubli.combelieve that this will expand our market www.pessolar.com 87share and our position as the partner of www.staubli-alternative-energies.com/choice when it comes to safe cabling/connectors in the PV industry. Bankability/bank.php

TALKING POINTCaught in the investigators’GSM network The future of solar farm security lies in communications technology. And in an optimised cooperation between security service providers and authorities. PES wanted to find out what advancements had been made at viamon since last hearing from them. Oliver Strecke Worldwide – but especially in sun-drenched systems from specialised and often regions such as the so-called Sun Belt near well-organised gangs of thieves is a88 PES Solar the equator – the number of large solar farms complex challenge for security service is growing continuously. But the providers. After all, the security-relevant environmentally friendly production of objects are placed – visible to everyone – electricity and heat with solar collectors is under the open sky. now also booming in regions that are comparatively less sunny. In the UK, for Solar farms are, of course, not placed on example, more and more agricultural land is greenfield sites completely unprotected. being used for the ‘cultivation’ of photovoltaic But many operators of on-grid PV systems (PV) modules to harvest solar power. have already found out that their technological assets are not sufficiently However, the valuable solar modules protected by fences, surveillance cameras arouse desires. Protecting installed and alarm systems alone. A fact that also

TALKING POINTaffects off-grid systems, such as water together forms a highly sophisticated, were equipped with viamon MDS sensors,pumps or smaller home solar systems. The high-performance tracking system: The invisible from the outside. The fact that notthieves usually come at dusk or at night, hardware, a smart connection box, and a every module had been chipped in thisthey are well equipped, unscrupulous, and modular component consisting of motion case has a reason: It is both more effectivefast, and often have well-functioning sensor, GPS sensor, GSM modem and and cheaper to chip the modules in groupslogistics and distribution networks. The battery, are, as mentioned above, only one rather than individually.biggest challenge is therefore the effective part of the solution. The second part istracking of stolen collectors. made up of viamon’s services. Presumably the sensors were paralysed for a short time with GPS and GSM jammers,Need for new, smart solutions with The advantages over conventional security, but the thieves’ joy did not last for long.long-term effect which relies solely on obstacles, motion Apparently, they weren’t technically skilled detectors and video recordings, are enough to remove the concealed sensors.It is difficult to quantify the annual damage obvious: if neither fences nor acoustic Four weeks later, the stolen modules werecaused to solar system operators and their alarms have provided sufficient defence, detected with an accuracy of a few hundredinvestors by theft. ‘Insurance companies do the modules can be dismantled, loaded, metres about 20 kilometres south of thenot provide clear figures on this,’ stated and reused elsewhere faster than security solar farm using GSM triangulation.Oliver Strecke, Managing Director of services or the police can do anything toviamon GmbH, in an earlier PES interview in prevent this. The successful location is a success for2014. ‘In any case, it is certain that insurers viamon and is, as already part of theirhave a great interest in improving security Often the thieves wear masks or act outside service package, which includes not onlyand that the issue is currently a hot topic for the areas monitored by CCTV, so that even consulting at the beginning of each project,the entire industry.’ highly sensitive cameras cannot provide the customer-specific use of technology, meaningful images that would help to but also locating and tracking services inviamon GmbH is currently the only provider identify the persons involved. It is not an emergency. As if that were not enough,of GPS/GSM-based security systems uncommon for surveillance cameras to be the company also takes care of contactingspecifically developed for solar systems. put out of action simply by a cover or by the responsible local authorities and, ifThe bustling full-service company based in force in the run-up to the theft. necessary, cooperates with other securityKaiserslautern, Germany, relies on locating, service providers involved.identifying and, this is crucial, tracking the But stolen PV modules do not have to bestolen goods in its security concept. By lost – as the case of a solar farm in central viamon systems are used all over thecombining proven communication England demonstrates. Here viamon were world, including in Germany, France,technology specially adapted to the use able to prove that they are on the right track Austria, the United Kingdom, Spain,with PV modules and a service package with their holistic approach. Switzerland, Namibia, Ghana, Nigeria,tailored to the needs of the solar industry, Chile, India, China, and the Dominicanthe company is treading a new path. The case Republic. The company is represented in the UK with several projects. ‘The use ofThe idea of chipped PV modules plus In December 2017, 140 Rec 260Wp our system makes sense both where weservices is as simple as it is ingenious and modules were stolen from a large solar farm can cooperate with the authorities and in central England at dusk. Some of them www.pessolar.com 89

TALKING POINTwhere tracking is not guaranteed in with the viamon system are considerably or – as in the example described – if thecooperation with state authorities and higher than with the exclusive use of stolen goods were possibly sold via portalsprivate security companies are involved conventional security technology such as such as eBay.’instead,’ explains Oliver Strecke. fences and video recordings,’ adds Oliver Strecke. ‘The effectiveness of our What is important to him, underlinesStolen PV modules are tracked by technology extends over all phases of a Strecke, is that his company continuouslyan app potential or actual theft. viamon’s system is engages in gentle pressure where pre-emptive, reactive, and supportive. Its convincing or lobbying efforts are required.viamon customers can also get an overview greatest advantage lies in the possibility of If Facebook today must take political andof the current status of their systems tracking the stolen property long-term.’ perhaps also a legal responsibility for theirthemselves and make sure that they are still data policy, why should providers like eBaycomplete – or track stolen PV modules, if Continuous development at all levels not be held responsible for not preventingnecessary. Their position can be called up illegal sales in the future?at any time via a web portal or a The staying power is therefore also asmartphone app. The transport route is hallmark of the company. This is not only ‘Security solutions for the solar industryrecorded and all available data delivered by evident in the fact that the boss himself has require holistic commitment. However, ourthe implemented system is displayed on travelled to the UK several times to push for focus is of course on the furthermy.viamon. The personalised portal also the clarification of the above-mentioned development of our own solutions, whichallows customers to determine who is to be case. Another example is viamon’s can become more and more anticipatorynotified in the event of an alarm. Alarms can development team that works on the based on the experience we are constantlybe received and further processed by the sensitivity of the sensors used for each gaining,’ Oliver Strecke continues. ‘Our goalresponsible staff either by text message, customer until they are optimally adjusted is to reduce the cat-and-mouse game to ae-mail, smartphone app or by phone. to the ambient conditions on site. This single, fast seizure with the help of our means until no sheep or wild animal grazing smart viamon sensor boxes and ourIn the case in point, viamon employees between ground-based modules can services – before the mouse hasinformed the responsible police station. trigger a false alarm – while at the same disappeared into the hole.’However, the officers only moved out time the chips remain sufficiently sensitive.several days later to secure the stolen www.viamon.comproperty and did not find it at the location Optimisation is known to be an ongoingdetermined at that time. process. The team in Kaiserslautern is About viamon currently intensively evaluating the latestPV module tracking with viamon’s MDS experiences. The development of a new viamon produces and sells securitycurrently possible for up to one year GSM monitor, which can reliably detect systems for photovoltaic power plants. changes in GSM radio signals and thus The company’s customised systemsHowever, viamon was not discouraged by trigger an alarm immediately in the event of consist of self-developed hardwarethis. ‘Sometimes it’s a cat-and-mouse jamming, is already in full swing. In addition, and alarm response services to securegame,’ declares Oliver Strecke. ‘But we are MDS sensors in the PV module and and optimise the production sites ofdefinitely the ones with more staying inverters will support jamming detection. renewable energy. viamon works withpower.’ The chipped modules can be EPCs, power plant operators (O&M),tracked worldwide via GSM and GPS over a A new generation of sensors will provide major global insurance companies andlong period of time, as they recharge their even more safety. And like all tasks, viamon PV module manufacturers to securebatteries whenever there is light. also addresses the issue of interfering both large multi-MW power plants and transmitters on more than one level. In smaller dedicated solar systems.A new generation of sensors is currently questions concerning the GSM connection viamon is one of the very fewbeing developed that has an even longer detection attempts, viamon cooperates companies that focus on the protectionservice life than the sensors used today – with Deutsche Telekom. This cooperation of PV modules and inverters.but in this case, the service life of the cells could help find a useful fall-back solutionwas more than sufficient. After another six for cases where GSM jamming messages With their GPS-based geo fencing anti-weeks, the stolen modules were detected do not occur, even when jammers are used. theft system, viamon were the first toagain via GSM in Cornwall. develop an integrated monitoring Security solutions for the solar industry solution for photovoltaic power plants.Again, the viamon team immediately require holistic conceptsinformed the local police, who immediately Since 2011, their technology has beenmoved out and found the ‘hot stuff’ For viamon, such cooperation, which is also applied in Germany, France, Austria,installed on the roof of a warehouse. The maintained with operators, security the United Kingdom, Spain,owners were charged but claimed not to professionals, authorities, and insurers, is Switzerland, Namibia, Ghana, Nigeria,have been involved in the theft because essential for the success of their own Chile, India, China, and the Dominicanthey purchased their PV system on eBay. solutions. Coordination with other security Republic and secures more than 500Police are still investigating – currently the service providers is important to develop MWp of installed power.seller on eBay. Retrieval operations were viable overall concepts for every customer,still running at the copy deadline. emphasises Oliver Strecke. ‘On the other In the UK, viamon is currently hand, there are, of course, areas over which represented with 300 MWp.‘Despite some hurdles, it has become clear we have no direct influence. For example,that the chances of tracking down stolen the work of the law enforcement authoritiesmodules and returning them to their owners90 PES Solar

Energy for a be�er life Electrification of Ahlaf, Morocco Photo: Cleanergy Mini-grid ...Smart and Flexible EnergyDirect mini-grid feeding of VarioString Xtender & X-Connect Xtenderrenewable energy + +VarioTrack Xtender AC-Coupling Full flexibility in combina�on+ with different grid-�eDC-Coupling Centralized main power system with inverter brandsDirect use of self-produced off-grid inverters and MPPT solarsolar power with mini-grid charge controllers Xtendersupport Back-Up Secures the most important loadsMeet with us at our booth B2.470,in Munich, Germany, June 20 - 22, 2018 www.studer-innotec.com

ASK THE EXPERTSIKEA’s flagship store in Singaporewith ABB InvertersA complete range of sunto socket options Leonardo Botti, Global Head of Product Management, ABB Solar, talks to PES about their solid technical expertise and knowledge. His company continually invests in R&D and has a wide ranging portfolio of integrated services and solutions. Leonardo Botti PES: Welcome back to PES Solar/PV Today, our global footprint in solar is publication. Thanks for talking with us. For extensive. We have active sales and service92 PES Solar the benefit of our new readers would you in more than 100 countries worldwide, like to begin by explaining a little about the dedicated solar specialists in more than 30 background of ABB and the importance of countries and five operation facilities. the Solar/PV industry to you? Our agility and international presence Leonardo Botti: ABB Solar has over 10 enables us to expertly navigate and focus years’ experience in the solar inverter on growth in mature and developing sector which is underpinned by solid economies, while keeping pace with technical expertise and knowledge in the emerging technologies such as storage, power conversion industry, where we have smart grids and microgrids, as well as been active for over 40 years. reacting to local market requirements.

ASK THE EXPERTSAs such, ABB is consistently investing in focused on power generation. installation of 60 ABB PVS800-IS inverterR&D with extensive testing and stations, each rated at 6MW, to providedevelopment of its portfolio to deliver We see the potential in driving global growth, clean energy to power the data center. Theintegrated solutions and lifecycle services as the market broadens and continues to all-in-one solution also included 60which optimise performance, reliability and spread across new geographies and environmentally safe, dry type transformersreturn on investment of any solar emerging countries, across residential, of 3.6 MVA, which are designed to provideinstallation, and fulfil the requirements of commercial and industrial, along with Utility the best performance throughout thelocal markets. and Microgrid applications. lifetime of the plant; ABB SafePlus CCV SF6 insulated compact switchgear and ABBWe offer a complete ‘sun to socket’ PES: We see you offer a range of high Power Plant Controller for controlling andportfolio, as we make ardent strides to voltage products; please can you tell us monitoring the solar plant.ensuring our solar technology is a leading more about what they are and theirsustainable energy source for distributed importance to EPCs, project developers Another high-profile project has been inpower generation and building applications. and utilities? Singapore together with Phoenix Solar forOur portfolio includes everything from LVdc leading furniture retailer, IKEA. We suppliedcomponents and MVac turnkey solutions, LB: The Solar market is shifting towards new 20 innovative TRIO-50 solar inverters tofrom transformers and medium-voltage cost-effective platforms, offering extreme power a rooftop solar system on IKEA’stechnology, to integration, solar and energy high-power string inverters with ratings of flagship store in Singapore. The system isstorage with our ABB free@home offering 100 and 120 kW, as opposed to traditional expected to generate 1.3 million kilowattand EV charging solutions. 50 to 60 kW for these applications. (kW) hours per year — enough renewable energy to power more than 280PES: Are you currently experiencing Higher voltage levels enhance the households. With this rooftop system,more growth in this market? In what optimisation of power generation through IKEA expects to trim an estimated $2.4areas particularly are you seeing longer strings of PV panels with reduced million from the store’s electrical bills overthis growth? system costs. the next ten years.LB: In the past, the solar industry was Technology is also increasing the voltage Like IKEA, the rest of the corporate sectordominated by a few markets including the levels on the AC side enabling higher power is poised to build more rooftop solar plantslarge gigawatt heavy weights of the USA, density, lower losses and more compact in the coming few years owing to the rapidlyGermany and Italy. The present and future power blocks. increasing economic viability of solarwill continue to see the shift from feed-in power. According to GTM Research,tariffs to the adoption of self-consumption The market, therefore, is naturally moving commercial rooftop installation costs haveand better, more efficient storage towards higher voltages and higher power declined almost 30 percent in the past fivecapabilities. In utility-scale PV, the market is classes / ratings to take advantage of years driven largely by falling solar panel reduced OPEX and CAPEX for the total costs. Solar has allowed corporate solar system cost, whilst also benefitting from customers like IKEA to achieve financial greater efficiencies, reduced environmental and operational savings in addition to impact and improved reliability. carbon footprint goals. ABB is focused on designing products and PES: What role does R&D have in ABB solutions which bring down the whole and what are you working on now? system costs for solar installations. Increasing the output voltage capabilities LB: As a leading supplier, it’s essential we can consistently reduce the Balance of keep pace with and anticipate our System costs. This can also impact cables customers’ demands and we currently and component expenditure as well as invest heavily in R&D. reducing losses thanks to lower currents. Moreover, using larger PV clusters and We believe time-to-market for new higher power units means there are fewer innovations is a key factor in determining units to manage, with a consequent saving our success and its essential we deliver on plant logistics and O&M costs. solutions that are relevant for our customers and deliver it cost effectively. PES: You appear to be involved in several high-profile projects recently! For example, it is no longer only about Are you able to tell us about any making the inverter more efficient, but impressive or noteworthy projects you using intelligent inverter technology to are working on? optimise the total system efficiency and Levelised Cost of Energy (LCoE) of the solar LB: We are very proud of our global solar plant. Advanced communication interfaces projects as more and more countries and intelligent remote monitoring and innovate and incorporate solar into the control are also essential to maintain grid design and architecture of commercial, stability as more and more solar is fed in. residential and industrial builds, and governments realise solar’s capabilities in PES: How important is training to you as meeting increasing energy demands and a company, in view of the stringent savings on energy costs. health and safety regulations? One of our recent utility projects involved LB: ABB has a strong commitment to partnering with Spanish independent power support the generation of safe, clean and producer ACCIONA to supply an all-in-one sustainable power. We believe in working in inverter solution for the 246 MWp El Romero partnership with our customers and third Solar Plant in the harsh environment of the parties by providing comprehensive training Atacama Desert in Chile. at every point of the solar value chain, from The El Romero project included the www.pessolar.com 93

ASK THE EXPERTSRobben Island Microgridsales through to the installer, service partner beyond, what trends and/or changes are determine the increased uptake ofand customer. Technicians working on one you anticipating in the market and why? digitalisation and deliver greater need forof our installations have to be certified by the solar power and storage.ABB University which gives them greater LB: The key determining factor for futuretrust and confidence in the system. solar plants will be the overall system Thanks to digitalisation, and integrated efficiency, stability and all the interactions technology platforms like ABB Ability™ itPES: Where do you operate and where within it. We envisage IoT and digitalisation will be possible to improve performance,are the key markets for ABB and are becoming an integral part of the PV design uptime and yield with reduced CAPEX andthere any areas, geographically specification and ongoing management of OPEX costs related to the installation,speaking, that you would like to break the PV Plant and installs, which will of commissioning, as well as any soft costsin to? course vary according to the demands of associated to renewable energy projects. the market.LB: As mentioned earlier, our global Having a clearer picture of assetfootprint is extensive as we operate in more For example, utilities will want digitalisation performance and health and being armedthan 100 countries worldwide. As the to support greater stability and Demand with the capabilities to undertake remotemarket becomes more fragmented and Energy Response, whilst in the residential asset monitoring and condition-basedgeographies broaden, coupled with the and commercial markets, smart technology maintenance, will be a great step forwardwidespread acceptance of solar as a viable and the appetite for greater connectivity in simplifying workloads, structures andrenewable power source, we see part of our and convenience will drive the future of reducing costs in line with modernchallenge being focused on offering digitalisation in the residential solar market Solar needs.relevant solutions and products. as prosumers take back control of their energy use. Today, the solar industry should not onlyWe need to be agile and fast in new markets, focus on how it can produce cleaner energyfor example in South East Asia, Latin As utilities and operators review the but on how it can be controlled, integratedAmerica and the Middle East, whilst interaction between renewables and and balanced through IoT and digitalsation.maintaining growth in existing countries and consumption following the emergence of The Solar industry is poised to lead theestablished markets in Europe, but also for prosumers and the rising costs of energy charge on digitalisation to create a moreexample in India, Australia, Japan or the US. supply, Demand Energy Response and sustainable, consistent energy flow. Virtual Power Plants are likely toPES: Looking ahead into 2018 and www.new.abb.com/solar94 PES Solar

THEY CAN RUN BUTTHEY CAN’T HIDEYour business will be Accepted by leading Cost protected 24/7. insurance companies. reduction. viamon offers a revolutionary viamon.com solution for the security of any PV power plant.

ASK THE EXPERTSMini-grid solutions:the available optionsMini-grid electrification of mountain cabins, Switzerland. Photo credit: Studer Innotec Mini-grids have become the solution for efficient and economic electrification in developing countries and in remote areas. PES gets an overview of the different configurations available from Pablo Muñoz, Technical Support Manager at Studer Innotec*. He will also be a guest speaker, at the Intersolar Europe Conference 2018, on this topic. PES: Welcome to PES Solar/PV nationwide distribution networks. It is easy magazine. Thanks for talking with us. to find more specific definitions online but Being a mini-grid expert, perhaps you they are sometimes contradictory. At could start by clarifying the terminology Studer Innotec, we use the term mini-grid used in this field. For instance, mini- to describe an energy system with distinct grids, microgrids and nanogrids, are economic entities between the producer/ these many names for the same thing? operator and user/consumers. More than a specific technological solution, it is a Pablo Muñoz: Yes and no. All three terms business model. refer to an electricity distribution network that is smaller than typical regional or PES: Please tell us why you think we Pablo Muñoz *Studer Innotec is a Swiss manufacturer of power electronics for battery based systems.96 PES Solar

ASK THE EXPERTSshould use mini-grids for electrification? On the bright side I like to think about the PM: In this case, the central inverter mobile phone paradigm, where the communicates with the individual systemsPM: There are several reasons for using a decentralised solution has prevailed over by varying the AC frequency. The frequencymini-grid. For economic reasons, because the fixed phone line, especially where there is a very robust information carrier, which isfor example, extending the national grid to is a lack of facilities. I envisage a very not influenced by the quality or distance ofcertain areas of a country can become very similar development in the energy sector, the distribution line.costly. Also to obtain a reliable network, due where the mini-grid will play a key role into the fact that in some countries the national rural electrification, especially in places The voltage is set at 230V, no information isgrid is heavily used and may be subject to where the centralised grid infrastructure carried by the voltage, and the frequencyblack-outs. By having an autonomous grid hasn’t been developed. varies between 48 and 54Hz. When thethe electricity is guaranteed. And of course, frequency is above 50Hz the centralrenewable energy is cleaner than both fossil PES: Could you please describe how a batteries are full, indicating that there is a lotfuels and nuclear power. mini-grid is set up, from technical of energy available to be used by the standpoint? distributed systems. In contrast, when thePES: If mini-grids are so great, why frequency is below 50 Hz the centralaren’t there more of them? PM: Several hardware configurations can batteries are discharged, and there is no be used to set up a mini-grid. According to extra energy available for the other systems.PM: The main difficulty of implementing customer needs, it may be a distributed ormini-grid projects is not technical, but a centralised electricity generation solution. By reading the frequency of the system, thedefining a business model around its The electrical line is the central carrier distributed inverters know the state of theimplementation: how to fund the project, distributing the energy to different users. central battery and by comparing it withmake a viable business out of it, how to The mini-grid usually integrates the their own battery status will determinesecure the investment, how to regulate/ end-user connections as well. whether they could feed or take energystabilise the consumption, and how to from the mini-grid.equally allocate the limited resources. Six years ago, Studer Innotec installed a mini-grid with distributed energy generation Depending on the size and number of and frequency control in the Swiss Alps at distributed systems in the mini-grid, the Mayens Sur le Scex. Over time this solution power limit and daily energy allowance are has proven to be robust and stable. set for each system so that no individual user can consume more than their fair PES: We would like to know what you share of excess energy. mean by a distributed mini-grid? There a more detailed description of these PM: In a distributed mini-grid each house, rules on our website. I recommend readers in this case 32 chalets, has its own to download the whitepaper ‘Mini-grids autonomous PV system with PV panels, with distributed energy generation and inverter/chargers and batteries. The frequency control’. individual systems are then linked together in a network, with a central inverter that PES: That is clever. You said that this provides voltage and frequency for the installation has been up and running for mini-grid. A set of energy management six years, what are the main points to rules ensures the energy exchange and the remember from this? successful operation of the mini-grid. PM: We have noticed that the use of PES: What is the benefit for an individual generators as a back-up energy source has system to be linked together with a been drastically reduced, providing central inverter? economic, environmental and noise level benefits for the community. PM: Once an individual system has fully charged its batteries, the additional energy The battery lifetime of the individual generated is lost. With a distributed systems has improved too. In winter, when mini-grid, the individual systems share their there is no access to the mountain cabins excess energy with the other mini-grid the batteries remain charged even if the participants, thus maximising the use of users’ solar panels are covered by snow available energy. thanks to the mini-grid. PES: That seems almost too good to be Over time, the power limit and daily energy true. Surely there must be arguments in allowance had to be increased as our first between the different participants calculations were too restrictive to make regarding how the excess energy use of excess energy. is distributed? One very important point is to involve and PM: Well, as it is indeed excess energy, educate the owners on how the mini-grid you will never share energy as long as works. By doing so, you avoid having to your batteries are not full. The goal is that depend on third parties once the solution every user maximises their own is implemented. consumption by reducing the battery cycling, whereas the excess or deficit of PES: Do you see any room for further energy is shared in the mini-grid to improvement? optimise the global energy utilisation. PM: As this is a flexible mini-grid solution, it PES: Please can you give an example of is possible to use different battery how the energy management rules are technologies and to use AC-coupling set up? connecting with all sorts of energy resources such as solar, wind or hydro energy. If www.pessolar.com 97

ASK THE EXPERTSMini-grid electrification of desert village, Chad. Photo credit: Trama TecnoAmbientalPower electronics of centralised mini-grid installation, Chad. Photo credit: Trama TecnoAmbiental installations, central or decentralised, are about empowering the beneficiaries andneeded, it is also possible to add a smart 2014 - 2015. The first three were installed in making the best out of electricity.metering function, where a tariff structure Chad by the Spanish company Tramadefines the quantity of electricity to be used TecnoAmbiental, on appointment by UNIDO PES: What are the main reasons Studeramong the mini-grid participants. and the Ministry of Energy in Chad. power electronics are chosen for mini-grids?PES: Please explain how a centralised All three solar mini-grids were installed withmini-grid solution is set up? a sustainable business management model PM: Mini-grids are often situated in remote ensuring their operation for the duration of areas where the dependence on thePM: A centralised mini-grid includes a the project lifecycle, which is 20 years. system is critical, making the robustnesscentral generation plant from which energy Local associations were created and and reliability of the installed products ofis dispatched through a distribution line to trained to handle day-to-day activities and utmost importance.the end-users. Just like with a traditional perform operation and maintenancegrid, a business model is required to services over the lifetime of the project. As experts in off-grid electrification for 30regulate the energy exchange with the users. years, we bring a long experience and PES: So far, what results have you had sensitivity for these kinds of projects. TheIn the centralised mini-grids I have been from these installations? scalability and modularity of our productsinvolved with, every user had a service- enable the mini-grid to evolve with thebased tariff scheme linked to an Energy Daily PM: Since the installation of the mini-grids, needs of its users, making it a smart andAllowance (EDA). The EDA is managed by both the tariffs and systems have had to be flexible energy source. Inverter/chargers ofsmart-metres called energy dispensers that upgraded, as the demand was high. The the Xtender series are compatible with mostprovide information to the users, controlling payment ratio is high thanks to the local brands of grid-tie PV inverters. You canenergy as well as limiting the current. commitment and the mini-grids are having therefore implement your preferred grid-tie multiplying effects in the neighbouring inverter brand in your system for ACHowever, every installation is different, and communities, who are beginning to ask for coupling applications.you always need to adapt the technology to their own mini-grids.the specific environment and type of usage We also offer value-added specificit requires. PES: How do you decide which solution functionalities, such as frequency control, to use? programmable auxiliary contacts, andPES: What experience have you had advanced system monitoring.working with centralised mini-grids? PM: A successful mini-grid installation should always be adapted to its context and built PES: What are your thoughts forPM: I had the opportunity to set up a total upon the community’s commitment. Mini-grid the future?of eight central mini-grids in Africa between PM: According to the Global Tracking Framework 2017 published by United Nations, 15% of the world population does still not have access to energy. Africa, excluding North Africa, faces the most severe challenge, as only 37% of the population had energy access in 2014. In addition, hundreds of thousands of off-grid installations are today powered by diesel generators. Replacing them or reducing their running time by implementing a mini-grid system will benefit our environment and make our children’s future brighter. A combination of a hybrid PV/genset is by far the best solution for off-grid electrification when needs are over 1-2kWh/day. www.studer-innotec.com98 PES Solar



PES ESSENTIALEarth first: greening the PVindustry with a universal zerowaste recycling concept!In this day and age recycling should be a top priority According to the latest revision of the EUthroughout the renewable energies sector. Dr. Palitzsch from waste legislation (WEEE), producers of solarLoser Chemie GmbH, reminds PES readers about the latest photovoltaic panels are responsible for theupdate to the EU waste legislation. It’s remarkable to see disposal and recycling of the modules theyhow it is possible to achieve total recovery of all materials, in sell in EU Member States. In addition to thisboth thin-film PV and silicon-based modules. we also have a few other reasons to recycle all and any used materials.Fig 1. Separation of front (1) and rear glass (2). Recycling allows the materials, in otherwise one-use products, to go on to become something new and saves resources involved in sourcing new materials: that´s why it is amazing. And the best way is, of course, the complete recovery of all components. In recent years, Loser Chemie GmbH has led the search for a universal concept, for as many solar module types as possible. Today, the company has introduced a technology that enables the recycling of both thin-film PV and silicon-based modules. An important role is played by light and water. Used correctly complete disassembly of old solar modules, into their individual components, is now possible. First of all, the application of optical technologies means the sandwich structure is easy to open and the glass panels do not have to be destroyed. This is important, because the price for recycling depends primarily on how much money can be generated for secondary raw material glass. This is also the decisive criterion for the choice of recycling. Usually two different grades of glass are used in one thin film photovoltaic module - front glass and rear glass (see Fig. 1). The front glass is of high quality, because it is also contains no iron. It is obvious, that a pure-grade secondary material of front glass has a higher value than the ferrous back glass. Contrary to conventional technologies, like shredding, we do not break the glass. By using technologies from the field of optical100 PES Solar