PES Wind 2016 - Issue 4

TALKING POINTHaving artificial intelligence technologyonboard accelerates our roadmap to fullautomation of the drone workflow.”Head in the cloudIBM and Aerialtronics have also justannounced the first commercial dronesfeaturing cognitive computing capabilitiesfrom the IBM Watson Internet of Things(IoT) Platform on IBM Bluemix Cloud. TheseUAS can provide high quality inspectionservices for global organisations acrossmultiple industries, from monitoring citytraffic patterns to inspecting wind turbines,oil rigs and cell tower optimisation.Now, rather than climbing 600,000 separate200-300ft towers, inspecting key areas andreporting back finds, teams can deployAerialtronics’ drones from the ground and,through high definition cameras andWatson Visual Recognition, gain a completehigh resolution overview, whileunderstanding what can be seen throughWatson. Drones capture the images inminutes and immediately send them to theIBM Watson IoT Platform to be analysed inreal-time.Robin says: “More importantly, the datacapture will be more reliable and accurate.The ability to verify aerial data in real-time,having the data processed in the IBM cloudand the ability to offload results in reportsstraight into the existing back-end for ourcustomers will accelerate theimplementation of drone technology in theinspection market. We can process datamuch faster with the IBM Watson Cloudplatform.” www.aerialtronics.com www.peswind.com 51

THINK TANKOPERA on the wavesWords: Paul Goodwin, Global Maritime, Pablo Ruiz-Minguela, TECNALIA, José Luis Aguiriano, OCEANTECFor all the growth in solar and wind energy over the past few years, one often over-lookedand untested renewable source is that of wave energy. Yet, wave energy is generallyconsidered to be one of the most concentrated renewable energy sources today and onethat is also complementary to solar and wind with the potential to help facilitate thepractical introduction of more renewables into the European energy grid.The different elements of the mooring system deployed at BiMEP this summer. Image courtesy of TECNALIAWave energy – opportunities and today – cost. It’s against this background the technology leaders and thinkers in wavechallenges that the European Union’s OPERA project energy. The members selected were: was born.The World Energy Council estimates that TECNALIA (Spain) who are the projectapproximately 2 terawatts (2 million The OPERA Project and goals coordinators of the consortium;megawatts) - about double current world OCEANTEC (Spain); Global Maritime (UK);electricity production - could be produced The OPERA (Open Sea Operating the Biscay Marine Energy Platform (Spain);from the oceans via wave power. The Experience to Reduce Wave Energy Cost) Ente Vasco de la Energia-EVE (Spain);European Union also forecasts that wave project has been set up to identify and IBERDROLA Engineering & Constructionenergy has the potential to supply some quantify the challenges experienced at-sea (UK); DNV GL (UK); the University of10% of European electricity needs - about in producing wave energy and to prioritize Edinburgh (UK); the University of Exeterhalf of today’s renewables total. the development and innovations required (UK); Kymaner (Portugal); Instituto Superior for solving them. OPERA has received Técnico-IST (Portugal) and UniversityYet, despite its attractiveness, potential funding from the European Union’s Horizon College Cork (Ireland).obstacles remain. Wave energy costs 2020 research and innovation programremain high compared to conventional under grant agreement No 654444. The rest of this article will provide a briefforms of energy and there have been limited overview of the key wave conversionopen-sea deployments to date. The The key objectives behind OPERA are to technology platform behind OPERA andcomplexities behind harnessing wave validate and de-risk innovations which can examine some of the technologies to be de-power have also led to a variety of designs reduce the cost of wave energy by at least risked. In particular, we will focus on theand technologies with little consensus as to 50%; and for the first time provide open mooring challenges around securing wavethe optimal approach. access to high-quality open-sea operating energy converter (WEC) technology. data (over two years) to enhance theThere is therefore an urgent need to share performance, reliability and survivability of The key technology – oscillatingdata and experience so as to avoid wave energy devices. The ultimate goal will water columnsrepeating earlier engineering mistakes and be to reduce time to market of wave energyto de-risk wave energy technologies to technologies and ensure a more mature It was decided to make a floating oscillatingattract further private sector investment, and commercially viable sector. water column wave energy converter as theensure the transition from R&D to key technology behind the OPERA projectcommercial operation, and bring down the In order to achieve this, OPERA needed a with Spanish company OCEANTECgreatest barrier to wave energy deployment consortium that would consist of many of designing and implementing such a device52 PES Wind

in a fully consented, grid connected, open-sea testing facility atBiMEP (www.bimep.com). The WEC – a 42-meter-tall spar typeconverter – will be deployed in October 2016 and is based in theBay of Biscay up to two nautical miles offshore in 85 meters ofwater.Oscillating water columns (OWCs) are simple constructions thatact like a piston and cylinder where – as the waves rise within theOWC – the action of a piston is replicated with the column of airahead of it being driven through a turbine. The OWC moves inboth directions (in and out) while the turbine rotates in the samedirection.Such devices offer a highly competitive ratio of power absorptionto structural mass which, when coupled with an efficient andeffective air turbine power take off (PTO), offer an attractivebase device for wave power development.To date, OWC technology is also the only wave energy extractiontechnology that has existing commercial applications – being usedin navigation buoys and the Mutriku wave power plant in northernSpain. It will be this power plant where the new turbineand control systems will be first de-risked, as described later inthis article.Using the OWC as the WEC technology platform, OPERA’s goalwas to de-risk four cost-reducing technologies innovations in thereal environment for open-sea wave energy applications. Theseconsisted of shared mooring and later elastomeric tethers, bi-radialturbines, and advanced control strategies. The flexibility of thesetechnologies was also important with – of the four innovations –

THINK TANKA Cable Laying Vessel for the OPERA Project. Image courtesy of TECNALIA.three were not specific to OWCs and were mooring lines can lead to substantially The WEC is to use a novel shared mooringtherefore able to benefit other WEC reduced costs. arrangement that consists of conventionalconcepts. tethers and a design where the mooring is At the same time, however, the security of configured for multiple devices, shares linesMooring challenges such moorings must never be and consequently reduces the number of compromised. Several WEC losses in the anchors. This leads to lower costs. GlobalOne of the biggest costs behind wave past have been traced back to mooring and Maritime will help ensure that the mooringenergy development today is that of short-cycle fatigue at the connection with system is robust and deliver telemetry andmooring. the hull. tension data, if required.Mooring typically comprises some 5-10% Another fundamental design question is Global Maritime will also provide assistanceof total costs for wave energy projects obtaining the necessary balance between on the definition of the underpinningalthough there are indications this may be the mooring restoring forces that secure the numerical methods to assess mooringan optimistic figure and that in large floating structure, while at the same time performance based on the data collecteddeployment depths costs can increase ensuring that the energy extraction modes from sea trial experience and will draw onsubstantially. from the wave energy devices are not its extensive experience in marine impeded. operations to indicate the duration andPart of the reason for this is that little has limits of operational windows.been done to date to customize mooring Effective mooring solutions must also bearrangements for floating wave energy able to withstand a wide variety of In partnership with DNV GL who will lead onconverters, with a focus instead on oil & conditions – from storm conditions and an developing technology qualificationgas standards and the mooring of large- ultimate limit state (where the individual methodologies and will quantify the riskscale semi-submersible drilling rigs. mooring lines have adequate strength to aspects of the components and systems withstand the load effects imposed by behind the innovations, Global Maritime willHowever, experiences in mooring other extreme environmental conditions) to a contribute to improving the overall designlarge-scale ocean structures, such as fatigue limit state as a result of cyclic of the project’s mooring and maritimeoffshore fish farms, suggest that an motions induced by the waves. operations, thus helping reduceintegrated mooring system can reduce uncertainties, risks and costs.mooring costs by as much as 50% in WEC It’s with these issues in mind that Globalarrays – a key objective of OPERA. Maritime will contribute to OPERA as an Elastomeric mooring tethers industrial partner with hands-on experienceHow can this be achieved? in the design, modeling, analysis and As the project continues into phase two in simulation of floating structures according the Summer of 2017, elastomeric mooringWhile depth, tidal current and tidal range to existing offshore standards and rules. tethers, developed by the University ofare key influences in the design and cost of Global Maritime also has a significant track Exeter, will also be tested as a means ofmooring systems, so are the mean and record in the delivery of mooring designs to reducing peak loads at mooring and hullextreme loads placed on them at sea. the oil and gas industry. connections. The University has overTherefore reducing the loads on the54 PES Wind



THINK TANK Deployment of the mooring system at BiMEP. Photo Courtesy of Oceantec Energies Marina. “One of the main challenges to OWCs today is the low efficiency of the airturbines that are often below 50%.”20-years experience in wave analysis, de-risked through OPERA include a at-sea implementation of control algorithmsresource modeling, marine hydrodynamics, bi-radial turbine and new adaptive and that act throughout the power conversionmoorings, testing, reliability engineering, predictive control algorithms. chain from the hydrodynamics of waveinstallation, offshore operations and absorption through to turbine aerodynamicmaintenance. One of the main challenges to OWCs today and electrical equipment efficiency. The is the low efficiency of the air turbines that OPERA objective from the de-risking ofThe mooring tether combines the material are often below 50%. Laboratory results, the technology is a 30% increase in energyproperties of elastomeric and thermoplastic however, indicate that a novel bi-radial production.elements, providing a ‘low stiffness’ when turbine could increase the annual turbinefacing normal operating conditions and a mean efficiency of OWCs by 50%. Both the turbine and advanced control‘high stiffness’ in extreme, storm-like innovations will be first tested at theconditions. As a result, OPERA will focus on advancing Mutriku shoreline wave energy plant and bi-radial turbines to a high level of later at BiMEP, an open-sea testing siteLaboratory results so far indicate that the technology readiness during the project, connected to the grid. BiMEP is a fullyelastomeric tethers can reduce loads by as delivering significant amounts of open- consented facility with supporting servicesmuch as 70% (an OPERA objective) with the sea data. – 24/7 surveillance, for example – thathope being that elastomeric mooring will contributes to further risk reductions.improve structural survivability and reduce Another challenge to successful wavemooring line strength requirements and costs. energy today is poor energy capture due to A crucial element of the future the narrow bandwidth of point absorbers – energy mixElastomeric tethers are also expected to wave energy capture devices. This is whygreatly enhance survivability with respect to OPERA will focus on new adaptive and Wave and tidal energy is a tremendouslya low-cycle fatigue failure mode for mooring predictive control algorithms that - at important element of the future energyconnections. virtually no additional cost - can greatly mix and is why OPERA has such ambitious increase power production and device goals.The de-risking of other technical reliability through using incoming waveinnovations information for increased control. From a 50% increase in air turbine energy efficiency to a 30% increase in energyOther technologies, in addition to the OPERA will therefore conduct the first production; the reduction of extreme loadsmooring solutions, that will be tested and by 70%; and 50% reduction in overall mooring costs in arrays, OPERA’s objectives are both bold and potentially groundbreaking. We look forward to unveiling some of our results over the coming months as we see a growing acceptance and deployment of this vital source of renewable energy. WECs in a shared mooring arrangement. Image courtesy of Oceantec Energias Marinas. For further information, please visit www.opera-h2020.eu56 PES Wind



THINK TANKThe lender’s engineer:friend not foeWords: Christos Kolliatsas, hydro and renewables director, Mott MacDonaldWith the potential exception of being a referee or a traffic warden, for the most part, alender’s engineer or lender’s technical advisor (LTA) may be one of the most polarisingprofessions available. And yet, a professional and competent LTA can bring significantvalue to a project, save a sponsor millions of pounds and can be personally rewarding. Project company Sponsor(s) Lender’s technical First things first – why do we need advisors PROJECT advisor an LTA? COMPANY OFFTAKER LENDERS The need for an LTA stems directly from the58 PES Wind CONTRACTORS involvement of lenders on a project. There Other lender’s are a number of ways of financing a project, advisors one of which is using debt financing. Depending on the level of financing O&M PROVIDER required from the lenders, there will be different types of products that satisfy the funding needs of the sponsors. In this article, we will be looking at project finance or non-recourse finance as it is also known. A basic schematic of project finance is shown below. As you can see from the diagram, the sponsors will typically establish a special purpose vehicle (SPV) or project company with the responsibility of making the project a reality – in our case a wind farm. The sponsors will be shareholders of the project company, but will not have any further liabilities to other funding sources. The project company will employ its own

THINK TANKadvisors for technical, legal and insurance is between the lenders and the project “Smart projectmatters – and with their advisors’ help, will company, the lenders typically have no companies have usedimplement a plan of action and ultimately recourse to the sponsors – thus the term LTAs to full advantageengage with contractors for the ‘non-recourse finance’. As you can imagine, by learning from theirimplementation and operation of the this does not sit naturally with lenders asproject. Furthermore, the company will institutions as they tend to be very knowledge”engage with an offtaker via a power conservative. To gain comfort that they arepurchase agreement (PPA) to sell electricity not throwing money away, the lenders will www.peswind.com 59and thus create a revenue stream for the engage with a number of advisors to assessproject. Depending on the performance of the project to establish any risks and tothe project, the sponsors should be able to determine if the risks are acceptable or not.get a return on their investment via a This is where the LTA comes in.number of streams. Role of the LTAThe sponsors are not alone in thisadventure. They either do not have all the If we were to put it in very basic terms, thefunds required or they do not wish to invest role of the LTA is to confirm the base caseall of their money in a single project. As assumptions of the financial model of asuch they will approach lenders to provide project from a technical perspective.typically between 70-80% of a project’s Typically this will cover:funding requirements via a loan. Thisarrangement allows the sponsors to de-risk • Energy yield assessment review totheir investments as they are potentially confirm the potential driver behind theable to fund, for example, five projects for revenue stream of the projectthe same amount of equity, rather thanrelying exclusively on the performance of a • Availability assumptions, similar to thesingle project. Lenders are therefore above to identify if the projections arerequired to carry the majority of the plausiblefinancial risk, especially at the beginning ofsuch a process as they are investing the • Capex projections – is the budgetmajority of money in the project. At the reasonable, justifiable and whatsame time, the lenders have no collateral as provisions should there be forthe project is just an idea and there are no contingency?assets built yet. Furthermore, since the loan • Opex projections – how much will it cost to keep it going to achieve the aforementioned performance?

THINK TANK Christos Kolliatsas, Apart from the assumptions of the financial • Central Europe – No constructionhydro and renewables director model, the LTA will need to be convinced contracts that the project can be built to a good quality standard and delivered on time. The There are many more examples of LTA will also need to confirm that the preventable situations arising in wind project will work at takeover and that it will developments, but the above highlights continue to work for the duration of its some of the basics. In most cases, the operational lifecycle as envisaged in the findings were discovered well into the financial model. The LTA’s process for project financing process which resulted in addressing all of these issues is complex delays in reaching financial close, inevitable and calls upon years of knowledge and budget adjustments to account for the experience in identifying risks, from the delays and of course items that needed to obvious to the obscure. For project be added on at a very late date. companies of course would rather not be questioned on their projects as it is often It is not only negative findings that LTAs seen as an interrogation of a project they discover. As part of standard LTA duties, we have spent years in developing in the best have managed to improve energy yield way possible. And yet, such interaction predictions, reducing the uncertainty of the should not be seen as an interrogation, but energy yield, thus resulting in a much instead as confirmation that all is well with smaller spread between P50 and P90 the project and – if the LTA is good – will be projections, which in turn improved the an opportunity to improve the project. financial picture of the project. We have assisted in making construction contracts Lessons robust, allocating the risk to the right parties, thus removing the risk from the Inevitably, and understandably, personnel project company which could have resulted with the project company will be completely in significant overspend. Based on our view absorbed by project details. This is good as of the marketplace gained from the number it is fundamentally important that the details of projects we work on every year, we have are correct. However, this also often results been able to advise project companies as in the bigger picture being lost and the to what is the norm in the market and impact of decisions that are being made as enable them to secure better terms. Smart part of the normal development process of project companies have used LTAs to full a project not being fully appreciated and advantage by learning from their understood. Once a decision is made, it is knowledge. This is only achievable if there very difficult for developers to backtrack on is open communication between the parties some basic fundamental questions such as and an appreciation of the value that an LTA will it fit, will it take the weight, does it all can bring. come together, etc. Conclusion A few examples from some unfortunate but true findings of wind energy developments: Sponsors who seek funding via project finance for their project are likely to • Asia – No substation encounter an LTA at some point in the process of seeking project finance. A • Central Africa – No transmission lines competent LTA should be seen as someone who can add value to a project; not • Latin America – Wind turbines were being necessarily a negative force. By viewing the delivered in Spain LTA in a positive light, the project, and in turn, the sponsors have much to gain to • Northern Europe – Never-ending base benefit their investments. price in the PPA mottmac.com • Southern Europe – Developing on disputed land • Offshore – No vessel60 PES Wind



PES ESSENTIAL62 PES Wind

PES ESSENTIALLooking beyond 2020– what lies ahead?We look at the European Wind Energy Association (EWEA)’s view of the future energylandscape beyond 2020.Current targets set out for 2030 in Europe to meet 10.2% of the EU’s electricity European citizens. This deployment haswill see the wind energy sector and other demand. The scalability of wind energy has been underpinned by the development ofrenewable technologies transform the power helped it emerge as a viable alternative to an industrial base making Europe the globalsector and bring positive impacts to the fossil fuels for power generation. leader in wind energy.European power system and the economy aswe pivot towards the new normal of This growth, driven by stable and The industry has taken strides in cuttingrenewable energy becoming our main source supportive policy frameworks for technology costs and the financeof electricity. As targets set in Brussels call renewable energy, has placed the community sees wind energy as anfor renewables to make up at least 27% of European wind industry not only as a increasingly valuable asset. With the cost ofenergy consumed, Giles Dickson, Chief global leader in its own sector, but also wind power decreasing, new investors haveExecutive Officer of the European Wind amongst all renewable energy also been attracted to the sector includingEnergy Association invites policy makers to technologies. Wind energy’s share of global business and blue chip companiesgo beyond the bare minimum. renewable electricity generation has more such as Google, IKEA and Apple. Keeping than doubled in the previous decade this momentum will be critical to the EU’sIn their report ‘Aiming High’ published in achieving more than one quarter (27.4%) of standing as the global leader in renewables.February 2016, the EWEA examines the all renewable generation in 2013. Thisextra rewards of taking a more progressive trend is set to continue according to the Thanks to its early-mover advantage,view as a reminder to policy makers of the European Commission, which expects European industry has played a significantopportunity that wind energy presents. We wind energy to represent at least 43-45% role in the development of wind in non-provide a summary of the report here. of all renewable energy produced by 2030. European markets. Over 48% of European wind energy companies work outside theWith 392 GW installed, wind energy can be Wind power plants across Europe are EU creating opportunities for exportingthe single largest source of power operating on a similar scale as traditional goods and expertise.generation in the EU by 2030 ahead of coal thermal power generation, delivering clean,and gas. Wind energy already plays a affordable and reliable electricity to Already in 2012, EU exports of wind-relatedsignificant role in the European powersector. In 2014, the wind industry installed “Let me be very clear to our international11,791 MW in the EU – more than gas and partners: the EU will not sign just any deal.coal combined. Today wind energy canmeet 10.2% of Europe’s electricity demand My priority, Europe’s priority, is to adoptwith a cumulative capacity of 128.8 GW at an ambitious, robust and binding globalthe end of 2014. climate deal”Additionally, over the past 15 years, windenergy experienced a remarkable growth in Jean-Claude Juncker European Commission Presidentthe EU. In 2000 wind met 2.4% of the EU’s discussing COP21 in his State of the Union speechelectricity demand thanks to 12.9 GW ofinstalled capacity. By 2014, 128.8 GW ofwind capacity had been installed, enough www.peswind.com 63

PES ESSENTIALcomponents generated a trade surplus of More importantly, this approach would A copy of the full report can be found ataround €2.45 bn. This trade performance postpone much of the investments required www.ewea.org/fileadmin/files/has been constant since2008 with an for the EU to meet its long term greenhouseexception of 2009 when the generalised gas emissions reduction objective. In library/publications/reports/EWEA-global economic slowdown had a visible contrast, Aiming High and pursuing a more Aiming-High.pdfimpact. 55% of exports went to five ambitious wind power deployment, willcountries, one third to US and Canada. bring significant additional benefits in terms Delivering on Innovation of greenhouse gas emissions savings,In 2014, three out the top five global wind energy security and macroeconomic Innovations in wind turbine designs areturbine manufacturers were European benefits. opening up new sites for wind powercompanies (Siemens, Vestas and production. New turbine designsENERCON). In addition, GE Renewable In the High Scenario, 53.7% of electricity enabling operations in low wind sitesEnergy has recently cemented its consumed in Europe will be sourced by have been introduced in the market.European business operations. European renewable energy technologies, with The development of modular blademanufacturers are not only dominant in wind accounting for 28.2% of total designs has allowed for larger rotorthe EU but have also secured market electricity demand. This scenario will help diameters which otherwise wouldshares abroad. In contrast, the activities remove 111.6 Mt CO2 by not postponing have presented logistical problems inof emerging Chinese competitors are climate mitigation actions to the next transportation. These innovationsconcentrated in their home-market. generation. have enabled development in sites that may have not been viable a fewEurope should capitalise on its first-mover This would be a net positive for the EU years ago.advantage in developing wind energy, the economy with an additional €13 bn GDPmost cost-effective climate change resulting from the increased deployment of Site optimisation is another researchmitigation technology. wind and other renewables. The area which has helped increase transformation of the energy mix will also production. Taking advantage ofA global climate deal in Paris in December lead to a net job creation in the European advances in communication and2015 is only the beginning of a long Union with 366,000 direct and indirect jobs networking, modern wind turbinesendeavour to address our climate change in the wind industry alone. are able to share data with one-challenge as parties will start implementing another. These digital wind farmstheir Intended Nationally Determined Wind energy’s potential to 2030 and optimise production leading to anContributions. beyond will largely depend on more improved performance of up to 20% ambition from policy makers. To this end, a in certain sites.This will open new markets for renewables robust governance system should beand other climate change mitigation agreed to ensure Member States The offshore wind sector has also seentechnologies. To benefit over the long term collectively deliver on the 2030 binding remarkable innovation. In movingfrom its competitive advantage, Europe will renewable energy target and are rewarded further away from shore to harness aneed to showcase a successful energy for additional ambition. high and stable wind resource,transition building on the large scale developers and technology groups aredeployment of wind energy. In parallel, the European Commission examining floating offshore wind, should make concrete legislative proposals which has the potential of opening upThe ‘Aiming High’ report quantifies the towards a well-functioning energy market the Atlantic and Mediterranean seas.impacts of the Central and High Scenarios driving the transition away from a fossil fuel Trials for vertical axis turbines onlaid out in EWEA’s Wind Energy Scenarios based economy. Finally, a structural reform floating foundations are underway infor 2030. In the Central Scenario with the of the EU Emissions Trading System should the South of France, which could seeEU just meeting its 2030 climate and energy be completed to provide for a high and full deployment within the nexttargets, wind energy will fall short of stable carbon price, dis-incentivising decade.meeting one fourth of EU electricity investments in carbon-intensive anddemand. inefficient power plants.64 PES Wind



PES ESSENTIALWind reflections Steve Sawyer, Secretary General, GWEC, gives a global overview of wind power during 2015, a very positive year culminating in the Paris agreement in December. He predicts a steady growth in the industry over the next five years. Steve Sawyer Wind Power Leads All New course, the rapidly growing installation Power Generation levels and record low prices of both wind66 PES Wind and solar power. More than 150 nations gathered in New York, on Earth Day, to formally sign the Most of the members of the business landmark climate change deal which was community that attended the dozen or so agreed in Paris last December, an all too rare business gatherings in Paris in the margins triumph for multilateralism in a world that of the climate summit were much less desperately needed one. Outgoing UNFCCC ambiguous than the negotiators. They, and head Christiana Figueres, just named one of we, are clear on the direction of travel and Time Magazine’s most influential 100 people that renewables are the future. The in 2015, has predicted that the treaty will remaining question is whether we can enter into force no later than 2018, two years make the change fast enough to save the ahead of schedule. climate; or rather will we? We know that we can. It is now clear that we have the We need the extra time. While there are technology to do so; what is lacking are many positive signs, Mother Nature is the proper frameworks to shift private sending signals of another sort: weird investment in the right direction, to stop weather, droughts, floods, unprecedented subsidising fossil fuel consumption and Arctic sea-ice retreat, record high winter production with hundreds or thousands of temperatures and Greenland’s annual billions of dollars every year and recognise glacier melt season started two months that we need to completely decarbonise early. CO2 levels are rising at an alarming the global economy. rate and we are now in uncharted territory in terms of atmospheric concentrations of So what does the Paris agreement mean greenhouse gases, at least since Homo for us in the wind power industry? Not a sapiens have been around. great deal in terms that can be translated into turbine orders and project approvals At the same time, there are a lot of positive in the short term, but the medium to long signals: Elon Musk’s record breaking term signal is very positive. One thing launch of the Tesla 3; decadal low fossil fuel which is only just beginning to sink in with prices have had no appreciable effect on governments and the electricity industry, the growth of wind and solar; the Financial is that any credible scenario to stay below Stability Board’s pronouncements on the 2°C requires an emissions free power climate related risks to the global financial sector by 2050 at the latest, preferably system; Chin’s State Grid calling for first a sooner; and if the 1.5°C target is to be regional and then a global grid to transport considered, then it would be much sooner. clean energy around the globe – a new Silk Anyone making an investment decision to Road; the growing divestment from fossil build a coal fired power plant today is fuels by institutional investors; and of seriously risking having a stranded asset.

PES ESSENTIALQuite apart from Paris, wind power had yet Looking ahead, we see a period of steady into 4th place in the global cumulativeanother record-breaking year in 2015. After growth for the next five years. Asia will installations ranking, and had the fifthinstallations broke through the 50 GW for continue to lead and Europe will move largest market last year. Pakistan, thethe first time in a single year in 2014, we steadily towards its 2020 targets, although Philippines, Viet Nam, Thailand, Mongoliareached yet another milestone in 2015 as there may be some bumps in the road. In and now Indonesia are all ripe for marketannual installations topped 63 GW, a 22% North America, both Canada and the US growth. All told, wind capacity shouldincrease on the 2014 annual market; and seem poised for another round of growth, nearly double in the next five years.not only did renewables surpass all other and as Mexico’s energy reform getspower sector investments, for the first time bedded down we should be looking at a Other than climate, two other major trendscapital investments in renewables period of rapid development in that newly are having a major positive impact on thesurpassed all capital investments in fossil liberalised energy market. wind business.fuels for the first time. By the end of lastyear there were about 433 GW of wind In Latin America, Brazil will continue to Cratering pricespower spinning around the globe, a 17% lead, although Chile, Peru, Uruguay andincrease over the previous year; and wind now Argentina will make a contribution. In While very low wind prices havepower supplied more new power Africa and the Middle East, besides market characterised the US market for some time,generation than any other technology, leader South Africa, both Morocco and and the Brazilian and South Africanaccording to the IEA. Egypt seem poised for solid growth in the tendering systems have also generated low next five years, and smaller markets in prices for the last several years, we haveChina led the way, as usual, with a record Kenya, Ethiopia and elsewhere are moving. recently seen a spate of tender results in30,753 MW of new installed capacity, Egypt, Morocco, Peru and elsewhere withbreaking the previous record it had set, in In non-China Asia, India is the main story, what up until now were unheard of prices2014, for installations in a single year. China which has now surpassed Spain to move outside the US plains states – in the vicinitynow has more than 146,000 MW of windpower installed, more than in all of theEuropean Union. Last year it was the firstcountry ever to invest more than USD 100billion in renewables in a single year. Also,China’s new Five Year Plan covering the period2016-2020 has increased its wind power targetfor 2020 once again, up to 250 GW.Europe had a surprisingly strong year, ledby Germany’s record-setting 6 GW ofinstallations, bolstered by more than 2,000MW of offshore wind and the US markethad a remarkable 4th quarter, ending withan 8.6 GW market in 2015, much higherthan most had expected.Brazil, Canada, Mexico and South Africaalso had strong years, and we saw the firstcommercial wind farms in Jordan,Guatemala and Serbia. Perhaps the mostencouraging sign of all is the continuedproliferation of new markets across Africa,Asia and Latin America, spurred by theneed for competitive, clean, and indigenousenergy sources to fuel development. www.peswind.com 67

PES ESSENTIALof €40/MWh or below, and in the case of and the potential implications of this go far “We have provenMorocco, below €30/MWh. beyond the US market. Five years from now that we have the the US wind industry will be a very different affordable, reliable,Is this the new normal? Time will tell, and much stronger animal, we believe. competitive technologybut it is clear that the costs of both to reach our goals.wind and solar technology have fallen While we all have a lot of work to do, and Now we need politicaldramatically in recent years, and new and much could go wrong, I am more miracles in energycomplex financing structures are creating encouraged by the overall trends than I have markets around thethe conditions for renewables to be been in many years, perhaps ever. But we world; to ensure thatcompetitive in an increasing number of have lost precious time and we have to the transformationmarkets. Of course, some of this is move quickly and unambiguously in the happens quicklyexplained by the excellent wind resources right direction if we are to reach our goals. enough to leavein some of these locations, but the our children anddownward pressure on prices will For the second year in a row, the IEA has grandchildren acontinue, and not just in new markets. published an analysis of energy-related CO2 habitable planet”China is lowering its feed-in tariff for wind emissions which says that emissions werethis year, and will do so again in 2018. basically flat in 2015, as they were in 2014, the first time that this has happened in aUS market stability period of global economic growth. This is welcome news indeed, but now we have toThe United States, as a pioneer in the get the numbers going down, and rapidly.global wind industry as well as having someof the best wind resources in the world, has We don’t need technological miracles tohad much lower prices than most of its achieve our goals, although they wouldOECD competitors for some time, but the certainly help. We have proven that wedifficulty was always the on-again, off-again have the affordable, reliable, competitivenature of the US market, as it was technology to reach our goals. Now we needsubjected to short term policy frameworks political miracles in energy markets aroundwhich left policy gaps every few years and the world; to ensure that the transformationhampered the growth of the industry. happens quickly enough to leave our children and grandchildren a habitable planet.So it was very welcome news, and a bigsurprise to all except for those directly See more details and five yearinvolved, when the Congress passed and projections for the global wind industrythe President signed into law a long term out to 2020 in GWEC’s fresh off theextension and phase out of the Production press Global Wind Report: http://www.Tax Credit (PTC) which has been the main gwec.net/wp-content/uploads/vip/federal policy support for wind energy in the GWEC-Global-Wind-2015-Report_US. So the US wind industry now embarks April-2016_22_04.pdfon its longest-ever period of policy stability, www.gwec.net68 PES Wind



PES ESSENTIALIntertidal cableinstallationsThe Race Bank Wind farm is being constructed by DONG Energy approximately 27kilometres off Blakeney Point on the North Norfolk coast and 28 kilometres off theLincolnshire Coast and Chapel St Leonards. It covers an area of 7511ha.Export cables bring the power from the wind farm to the substation onshore. Theseexport cables run through the Wash and come ashore east to the mouth of the river Neneand approximately 6 km northeast of Sutton Bridge. The cables ashore run further in asoutherly direction to the connections point at the existing Walpole Substation.The two export cables are both most important natural habitats. Mitigating intertidal cables. This was of paramountapproximately 70km long and the two any potential for the installation works to importance to the government and localOffshore Substations (OSS) are linked with impact on these habitats is a key priority community following challenges facedan interconnector of 4km. In March 2015 and measures to ensure that works would during previous cable installation works forJan De Nul was awarded a contract for the be conducted in the most appropriate and another windfarm in the vicinity.installation and burial of both export cables least invasive ways possible was agreed inand the interlink cable. accordance with the project’s consents. The first part between KP 0 at the sea defence and KP 2.0, which compromisesHere we focus on the installation of the Bathymetric levels in the intertidal areas saltmarsh habitats, had to be buried atintertidal parts of the export cables and its vary between +7m LAT to -8 m LAT with 1.5m top of product with a level of impactspecial challenges. tides ranging up to 7 m during spring. that would not affect the integrity of The Wash and North Norfolk Coast SpecialEnvironment Saltmarsh and mudflats Protection Area.The intertidal areas of The Wash Strict boundary conditions were imposed The second part from KP 2.0 to KP 8.0,compromise up to 10% of England’s through the environmental permit on the which is mudflats, had to be buried up tosaltmarshes and form one of England’s installation and burial methods of the70 PES Wind

PES ESSENTIAL-5m top of product. The ground carrying kN whilst in reality tension up to 200 kNcapacity in this area is very limited and the was measured. Pulling in of the cablerisk of bogging is significant. with the rising tide significantly reduced the friction on the rollers and the requiredInstallation pull in force.The export cables supplied to the project The cable pull in on the beach wasby NKT are 268mm in diameter and have a conducted in accordance with the basicweight of 108 kg/m. In total 2 cables of 8km principles of first end pull in’s with the mainhad to be installed through the intertidal winch ashore and cable pull in over rollers.zones. The flattop barge, DN120, with The innovation sits in the custom built tooldimensions of 109m by 27m and with that was developed to automate thedeadweight of 10,000 tons was converted deployment of the rollers and bury theto a cable transport and installation barge, cable with minimum impact to thecomplete with turntable, roller way and surroundings.cable engines. The engineering of the bargelayout was focussed around an equilibrated Sunfishdistribution of the weights on the barge, inorder to reach even keel with minimum Sunfish uses a Hitachi Zaxis 350, as centralballast water. The result was a success, power source, mounted on a light weightwith a loaded barge draft of only 1.85m, chassis with large bogie-wheeled tracks toresulting in the ability to beach at KP 2.0, as reduce ground pressure less than 20 kPaanticipated during tender phase. The and maximise traction. The cabin islocation for beaching is important as this mounted on an elevated tube at 5.5m abovedetermines the amount of cable that has to the surface to remain above water duringbe pulled ashore over rollers and the all tides. A large V-plough is mounted atassociated tension in the cable. The the back of the machine, capable of buryingmaximum allowed tension in the cable is the cable up to -1.5m to of product. The286 kN with conservative engineering V-plough is hydraulically operated frompredicting maximum tension of about 240 the control cabin. www.peswind.com 71

PES ESSENTIAL“On the right tide on On the platforms above the tracks, there is muddy surface. The required burial depth12 June 2016, cable a system installed for the automated beyond KP 2.0 increases up to -5m for pull-in commenced installation of rollers, at fixed distances of which a different tool, Moonfish, has beenand was successfully 3m intervals between the rollers. The rollers developed. are light weight design to minimise weight completed within onboard Sunfish and shaped as such that The burial device on Moonfish is a large hours afterwards” they are stackable into especially designed chain cutter with depressor box assembly. cassettes. The Sunfish is capable of The stroke of the hydraulic cylinders carrying 4 cassettes of each 110 rollers. In holding the chain cutter assembly is 4m. total 1320m worth of rollers at an inter- Depending on the length of the installed distance of 3m can be deployed without chain, the burial depth can vary between reloading the Sunfish. For this project more -2m and -6m or 0m until -4m. On top of length had to be covered and full cassettes, Moonfish, there is an adjustable quadrant with rollers, were placed at certain with also a stroke of 4 m to manage any predetermined points along the cable route slack during operations. by Sunfish before starting the operations. Due to its crane arm, Sunfish is capable of Moonfish is powered by 2 onboard HPU’s loading and off-loading roller cassettes which are fed through an umbilical from the without external assistance. installation barge. The installation is mounted on a similar light weight chassis Additional 50 Te traction for use during as Sunfish and has identical bogie-wheel ploughing is provided by connecting a tracks. The only difference is that Moonfish Dyneema rope to the chassis and on to a has grouser plates mounted on the tracks constant tension winch onboard the for better grip in the mud. installation barge. The entire machine is designed to work Sunfish is used for burial between the submerged and can withstand water sea defence wall and the installation barge depths up to 200 m. Controlling the at KP 2.0. Moonfish is done remotely from onboard the Installation barge in a control cabin, Moonfish similar as those used for conventional offshore trenching and ROV tools. The From about KP 1.4 there is very limited, to machine is loaded with sensors, camera’s no vegetation and the area is basically a72 PES Wind

PES ESSENTIALand tools such as blue view systems to to the predetermined locations for pit and up righted its chain cutter depressorenable full remote control. The umbilical is exchange of cassettes during the assembly ready to start trenching.managed by a constant tension winch, installation process. Next, Sunfish drove DN105 was removed from alongside DN120ensuring that sufficient tension is towards the shore whilst taking along the and grade-in Moonfish burial commencedmaintained on the umbilical to keep it messenger wire and Dyneema rope and with the DN120 laying cable during highstraight to the installation barge, to avoid simultaneously installing rollers. Once at tides and Moonfish catching up in between.the Moonfish running over it. The maximum the sea defence wall, the messenger wire The installation and burial process betweenseparation of Moonfish from the barge is was connected to the main pulling wire KP2.0 and KP 8.0 continued smoothly1000m. which was subsequently pulled towards the between 26 June 2016 and 8 July 2016 installation barge over the Sunfish, the where after the cable end was sealed andOperations rollers and the Moonfish and connected to laid down for future jointing. The DN120 and the export cable. Moonfish returned, in controlled steps, toThe intertidal export cable was loaded sufficiently shallow water near KP 4.5 foronboard DN120 from temporary storage in On the right tide on 12 June 2016, cable reloading Moonfish on to DN105.Zeebrugge beginning of May 2016, followed pull-in commenced and was successfully The installation of the southern 8km ofby mobilisation of DN120 to the site in the completed within hours afterwards. At the intertidal Racebank cable started as anUK. Simultaneously Sunfish and Moonfish first daylight the following day, Sunfish enormous challenge and its completion onwere mobilised onboard a separate barge started with burial operations driving time was a significant success, setting aDN105 from Antwerp after completing the towards the DN120 whilst recovering the new benchmark for shallow water cablepremobilisation testing programme, rollers. The burial process went smoothly installation and burial in environmentallyincluding dry dock endurance tests for as planned with the V-plough gently lifting sensitive areas.Moonfish. the ground and placing the cable underneath. www.jandenul.comOnce on site, DN120 positioned at KP 2.0,first on spuds and then on 5 anchors which At the transition zone near KP 2.0 aare installed and handled by the 3 assisting transition pit was excavated by a small LGPshallow draft support vessels. Upon arrival excavator to allow transition betweenon site, DN105 was moored alongside Sunfish and Moonfish burial at designDN120. During low water, ramps were depth. The cable was offloaded frominstalled and the machines were offloaded Sunfish with the onboard arm fitted withfrom DN105. quadrant and installed inside this transition pit. Moonfish reversed until the transitionWhilst Moonfish positioned in front ofDN120, Sunfish brought loaded cassettes www.peswind.com 73

TALKING POINTTesting, validation,an opportunity foroffshore wind powerWords: Prof. Dr.-Ing. Jan Wenske, Deputy Director IWES NorthwestDr.-Ing. Maik Wefer, Division Director Structural Components IWES Photographer: Dieter HergethJan Wenske and Maik Wefer of Fraunhofer IWES, show PES how testing should be regarded asa method to accelerate time to market of new designs and stand out by offering approved overallsystem reliability – instead of restricting the view to the one-time expenses. An opportunity toimprove turbines and technology and enhance the competitiveness. The positive outcomes,however, outweigh this expense by far.What can offshore wind turbine However, probably the greatest difference online monitoring and insufficient reliabilitydevelopment and wind farm projects be is that offshore turbines are more difficult to of parts and systems are a recipe forcompared to? Certainly not their onshore get to and access when in operation. Thus, technical, and therefore economical, failure.counterparts. The differences are obvious the operation of a turbine in an offshore We are talking about enormous investmentand include the following: offshore wind wind power plant has more similarities with sums in the multiple billions of euros coupledturbines are much larger and more powerful, a space mission than onshore wind with limited access depending on thethe wind and environmental conditions are developments: once the turbine leaves port, environmental conditions in the event of aquite different, the foundation structures and any kind of work becomes infinitely fault or failure. The manpower, the logisticalinstallation work are more complex, they are expensive and time-consuming or even expense and cost of transportation, be it shipconnected to the grid via HVDC (high- impossible for long periods. This is why or helicopter, are considerable.voltage direct current transmission) or their ultimate success or failure depends toconverter stations, undersea cable must be a very significant extent on the technical The failure of the tiniest safety sensors orlaid and, last but not least, the technical and reliability of components and systems. In serious damage to the rotor blades, theeconomic track record of this comparatively the field of offshore wind, general design foundation, the drive train or the electricalyoung industry is shorter. flaws, poor maintenance concepts, lack of system not discovered during operation74 PES Wind

TALKING POINTAt the Dynamic Nacelle Test Rig, wind loads occurring in the field are emulated by servo-hydraulic actuators in a Stewart-platform configuration transmittingmechanical loading on rotor shaft of the specimen. Photographer: Martina Buchholzcan result in the failure or malfunction of of industry (automobile manufacture, “Around the timeentire turbines. aerospace, railway construction and of the first major heavy engineering) are not applicable space programs in theTesting is a necessity, not a trend one-to-one, but demonstrate the general 1960s, research and direction and sense of large-scale trials for industry developedAround the time of the first major space testing and validating, in particular, for new test standardsprograms in the 1960s, research and offshore wind turbines, their subsystemsindustry developed new test standards and and components. In the opinion of and methodsmethods to increase the reliability of parts, Fraunhofer IWES, the combination of various to increase thecomponents and systems, informed also by tests and test levels (see below) as well as reliability of parts”the experience gained in the aviation and an overarching exchange of experience andautomotive industry. The HALT and HASS knowledge between test-centred researchtest standards for validating and generally institutions, industry and certifiers is usefulincreasing the reliability mainly of electronic in general, but without parallel for thesystems were developed and established at development and/or optimisation of generalthe beginning of the 1980s in parallel with standards.the accelerated digital revolution. Sometimelater the focus switched to quality • Special material tests (under complexmanagement (e.g. Six Sigma initiative, load conditions and multi-dimensionalintroduced by Motorola) in production. environmental influences; e.g. UV/Unfortunately, the terms quality and cosmic radiation, moisture, salt,reliability are today often incorrectly temperature, vibration, etc.)intertwined or even equated with oneanother, but a strict distinction must be • Tests of components and partsdrawn between them! Reliability is alwayslinked in a multi-dimensional way with time • Tests of assembliesand the temporal progression of loading,and operating and environmental • System tests (incl. software, hardwareconditions. In other words, a high level of in the loop, etc.)product quality in no way guarantees a highlevel of reliability, but is certainly a • Prototype and onshore field testsprerequisite for it. • Offshore demonstration turbinesMost of the standards for increasingtechnical reliability in established branches • Data acquisition and analysis of existing installations www.peswind.com 75

TALKING POINT Exploration and evaluation of support and foundation structures and affiliated Fraunhofer IWES’s work focuses construction methods are realised at the foundation test pit. Photographer: Tobias particularly on component and system tests Kleinschmidt on large-scale test benches, and these are presented here. All the significant interfaces of the hub/blade bearing/rotor blade group are tested under realistic conditions.Photographer: Martina Buchholz Rotor blades on trial76 PES Wind IEC 61400/23 requires that newly developed rotor blades must undergo both static and dynamic testing for structural durability. For this, after preliminary static testing in four directions, the rotor blades undergo cyclic testing in two load directions for a certain number of load cycles by excitation at their natural frequency. Finally, static tests must once more be carried out. Fraunhofer IWES currently has two blade test benches performing this kind of certification testing. To date, 20 new designs measuring up to 83 m in length have been tested for various clients. Improved test methods simulate realistic loads However, as blades get longer, the standards currently in use are themselves being put to the test. The increasing size results in very large test loads and low natural frequencies, which pushes up the cost and extends the time it takes to test. Besides the challenges for blade certification as a direct result of the longer blades, there is an array of disadvantages with the standards used today. The blade properties are usually only tested in two directions using simplified load scenarios, which means that it is not known what

TALKING POINT www.peswind.com 77

TALKING POINTTwo test rigs for rotor blades of up to 90 m in length are available for testing the latest generation Hanover, in which new dimensioning methodsof rotor blade designs. Photographer: Dieter Hergeth can be developed or existing ones can be validated based on large-scale tests onhappens over the entire cross-section of the economical concepts for this. Broadly foundation and support structure elements,blade. Furthermore, depending on the test speaking, there are two different support with the purpose of deriving dimensioningmethod, deviations between test loads and concepts: those designed for proposals backed by experiments. These willrated loads occur, with the consequence predominantly normal/axial loads and enhance turbine/power plant safety andthat some types of damage that arise in the those designed for predominantly lateral enable the manufacturers to achievefield cannot be observed in a blade test. An loads. Monopiles typically take the loads economic optimisations.improvement in the blade test in these laterally. While the theory has been thatrespects is leading to more realistic loading monopiles with a diameter of approx. 5-6 Field testing of blade bearingsand is thus better serving blade designers, m and up to 25 m water depth are and pitch systemsmanufacturers and operators. economically viable, in the last five years the practice has painted a different Statistics from field tests prove that theIn the past Fraunhofer IWES has tried picture. While the average monopile in pitch system including the blade bearing isvarious methods, including biaxial tests. 2011 had a diameter of five meters, today one of the wind turbine subsystems withHowever, most concepts still address only there are monopiles with a diameter of the highest failure rates at present. At thesome of the current challenges. For this eight meters at a water depth of around same time, the blade bearing in particularreason, Fraunhofer IWES has developed a 40 m in the Veja Mate wind farm. This is seen as a key chokepoint or risk factor,new method, which addresses the year, a Dutch company presented especially for the development of futureconcerns of the offshore industry in monopile concepts with diameters of up generations of turbines with capacities wellparticular: one project is currently looking to 11m. Monopiles currently have a market over 7 MW. In order to reduce the specificat segmented blades as the basis for share of around 97%. tower head masses and resulting direct andcertification. The advantage with this indirect costs, there is no alternative tomethod is that segmented blades do not The disadvantage is that there is no modern control methods like IPC (Individualtake as long to test, as the natural universal dimensioning basis for XL Pitch Control). However, these bring aboutfrequencies are higher. The experience monopiles, as the standard p-y method additional mechanical, tribological loadsgained and the development of new test [DIN EN 19902, 2014] was calibrated for – which cannot be reliably calculated atstandards based on extensive experiments, “long slender jacket piles with diameters of the moment – in the blade bearings and thefacilitate a quicker and more accurate less than 1 meter” [DNV, 2014]. As such, this pitch drives. There are two factors at playresponse to customer demands. method is not applicable without prior here: the increase in size and the atypical validation. Since the field tests required for operating loads due to the use of newScrutinising concepts for this are very costly, reproducible large-scale control methods. Currently failure causessupport structures tests can be an economical alternative. What and mechanisms primarily in the main is undisputed is that the scale effect works. bearings and the pitch drives are notThe support structures and foundation One solution to this issue is to revise the fully understood.systems are often the most expensive parts existing p-y curves both under static andof an offshore wind turbine. In some cases cyclic loading. For this, Fraunhofer IWES runs Fraunhofer IWES operates a pitch bearingthey account for 40% of the total cost, so a test centre for support structures in test bench for smaller onshore windthe industry is constantly looking for turbines. Based on the experience accumulated so far, another large-scale test bench especially for blade bearings and pitch drives for the next generation of offshore turbines up to approx.10 MW is currently being designed and set up. The project is flanked by broad-based, corresponding research activities in conjunction with industrial partners and the Institute of Machine Elements, Engineering Design and Tribology (IMKT) of Leibniz University Hanover. They range from preliminary tribological investigations, adapted, novel modelling for simulations as well as the development of suitable special sensor applications for online 2D lubricant film thickness measurements through to the development of appropriate test methods for accelerated life testing of blade bearings with a diameter of up to 5 meters. Testing is scheduled to begin in mid-2018 with test durations of max. Six months per blade bearing currently expected for the accelerated life test. In addition to state-of- the-art functionality (incl. IPC, dyn. 6-dof load application system), this test bench will feature a realistic simulation of the individual blade and hub interface stiffnesses. Validation of nacelles, drive trains and direct drive generators78 PES Wind

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TALKING POINTExamining the fatigue behaviour of large components The comprehensive medium voltage grid emulator for electrical system testing covers all possible gridunder multi-axial loading. Photographer: Jan Meier events and characteristics and helps shortening the certification process. Photographer: Martina BuchholzLarger rotors require more powerful drive On this system test bench all current thus fill in the gap that still exists intrains; this is a matter first and foremost not offshore turbines as well as next-generation validation for later phases of productjust of adapting the nominal output, but of turbines can now be subjected to extended operational life, similar to the well-knownimproved concepts, detailed solutions and function tests, development tests as well as HALT (Highly Accelerated Life Test)component development; e.g. in relation to accelerated tests or stress screenings. The methodology for electronic assemblies.main bearing, lubricant supply, cooling, test bench and its implemented, dedicatedcouplings, gearbox and generator hardware-in-the-loop system are designed Fraunhofer IWES operates several flexibleutilisation/efficiency coupled with for realistic test scenarios (turbine component test benches that can beincreasing reliability in order to reduce the operation). These kinds of tests facilitate the modified for the individual installation, andspecific life-cycle costs. Due to the concrete analysis of the dynamic interaction is planning to set up further facilities of theirexponential growth of the static and of individual components on the real nacelle- kind in the coming years. The advantage ofdynamic drive train loading, the reliable mainframe, with the original power cabling these test facilities is, that they areand economical dimensioning of parts and as well as using the real wind turbine specialise and more efficient to operate.assemblies is approaching the limit of the controller. Possible fault or wear causes andscope of current calculation models and mechanisms can be localised early and be Summarypractical experience. observed thanks to the use of special sensor technology and many measuring points. The Of course, the comparison, made at theThe use of scaling and other safety factors turbine controller and safety systems can outset, between a space mission andis threatening to become an intolerable also be efficiently optimised and validated in offshore wind turbine development is flawed.technical risk, or no longer allow for the relation to simulated failures modes (on rotor But one thing they do have in common thateconomical use of material. Such and grid side) on that test bench. cannot be dismissed is the extreme focus onsimulation and calculation models in this the need for technical reliability andarea have been validated not with one-to- Life time testing of sub-systems maximum availability. Fraunhofer IWES is ofone tests but with the aid of standardised is essential the opinion that, especially before the marketmaterial specimens, at best on highly launch of newly developed or modifiedscaled-down experimental models or on Fraunhofer IWES does not see the point in prototypes for offshore applications, the needstandardised parts such as screws and trying to perform accelerated life testing of for extensive tests and the feedback ofbolts. At Fraunhofer IWES various large- systems on the full nacelle test bench experience gathered in the field is essentialscale test benches for components and considering the length of time it takes and and deserving of special attention. The oftensystems are used in addition to special the cost involved. It does, however, automatic criticism of additional costs formaterial tests in order to validate advocate smart stress tests, which, similar testing does not seem justified whencalculation and simulation models. to the HAST (Highly Accelerated Stress compared with the investment sums and the Tests) of electronic assemblies, target potential subsequent costs in later operation.Central to this is the dynamic nacelle- failures early on in product use, or which,testing laboratory (DyNaLab) for testing when used in such cases, result in Testing should be seen not as a burden fordrivetrains, direct-drive generators and much-reduced failure rates. the offshore wind industry but as ancomplete nacelles between 2 and 8 MW. opportunity to improve the turbines andIts core components are: a high-dynamic Fraunhofer IWES believes that the technologies in use to make them godirect-drive in excess of 10 MW nominal recommended scope of testing for a new further and faster in the future, to increaseand 15 MW peak output, force-controlled offshore wind turbine includes much more their reliability and thus to reduce inherentservohydraulic load application system for than just system tests on a full nacelle test development risks and the cost of offshorethe main shaft hub interface of up to 2 MN bench. System tests are predestined to find wind power utilisation further.and 20 MNm in the frequency range up to weaknesses in general; only tests ofapprox. 2 Hz as well as an artificial assemblies and parts, e.g. for the main www.windenergie.iwes.fraunhofer.de/medium-voltage grid (grid simulator) for shaft bearing, the gearbox, coupling and en.htmlvoltages up to 47 kV – one of the most generators, derived from such system testspowerful and functional in the world – with provide the required safety and indicate thean installed converter power of 44 MVA. status of entire reliability. These accelerated endurance tests at assembly and part level80 PES Wind



TALKING POINTTaking the long viewUp until recently in the wind industry, the aim of many Jukka-Pekka Mäkinenplayers when affecting the choice of technology seemed President and CEO of The Switchto be based on making the wind turbine as cheaply aspossible. PES gets a different perspective from Jukka-Pekka Mäkinen, President and CEO of The Switch.“We believe looking only at upfront costs is As engineers of advanced drive trainextremely short-sighted,” states Jukka- technology, the number one objective atPekka Mäkinen. “The stumbling block, The Switch is to ensure that wind farms canespecially in emerging markets that are more produce the maximum amount of powersensitive to prices, is how project return is over their entire lifetime, rather than lockapproached. Investors are almost exclusively into the lowest initial investment costs.focused on increasing the project return on Although this idea may seem to be commoninvestment to anywhere between six and sense to most, it is a departure from theeight years. In reality, the lifetime of a recurrent investment mentality that hasmodern wind turbine and its associated dominated the wind industry throughout itsproject value, however, is 25 years.” relatively short history.When it comes to selecting critical Assessing your true O&M costs to avoidcomponents, like drive trains, decisions nasty surprisesdriven by CAPEX reduction will eventuallylead to higher operation and maintenance The claim that permanent magnet generatorcosts. Price-led decisions most often than (PMG) and full-power converter (FPC) drivenot lead to a backlash when turbine owners trains are more expensive than double-fedrealise that long-term reliability is induction generator (DFIG) drive trains isinadequate. fundamentally wrong.82 PES Wind

TALKING POINT“It is based on a gross underestimation of Some OEMs only sell standalone turbines nasty post-warranty surprises.the required servicing and total reliability of along with their maintenance and warrantythe drive train, which also must be taken contract without proper assessment of What’s more, PMG drive trains offer a highinto consideration to get a full picture of the changing grid performance levels, and level of serviceability. Operators need to beoverall costs of a wind turbine over its entire thorough consideration of the growing able to service turbines as easily aslife cycle,” Mäkinen explains. post-warranty servicing needs related with possible in case of failures, especially DFIG designs. offshore. They need to be able to executeWhen assessing failures, the main criterion all repairs onsite, without taking theis downtime. What matters is the impact of A lifetime without failures with components out of the nacelle. And theyfailures on the relative extent of the simpler solution certainly don’t want to take the whole drivedowntime they cause. Although potential train down to replace it with a new one,failures over a 25-year lifetime are not easy Advanced drive train designs based on the since this is expensive and time consuming.to forecast with great accuracy, the wind use of a permanent magnet generatorindustry’s practical experience has shown significantly improve the reliability of the Reaching longer-term goals with thethat the gearboxes associated with DFIG overall system. With PMG designs, there right choicedrive trains are a primary cause for failure. are virtually no weak parts. The project owner can reasonably expect the machines The Switch has built a robust and advancedWind turbine failures are likely to occur to reach their full 25-year lifetime without drive train based on PMG technology thatevery eight or ten years, which is any failure. In fact, the reduced servicing has allowed the company to penetrate intounfortunate given that in most cases the costs alone can sometimes be enough to a traditionally conservative market. Thewarranty runs for only five years. Beyond justify the selection of high-efficiency PMG touchstone of its key components’ reliabilitythis time, the likelihood of failures increases drive train technology. has always been the simpler, the better.even further. For example, when looking athigh-speed solutions, the costs associated “Reducing the number of components is “By achieving this ambitious vision, wewith gearbox repairs or replacements must important, because this leads to reduced have been able to show the wind poweralso be taken into account. Such risk. The Switch’s PMG drive trains industry and other traditional industries asmaintenance requires cranes that can often eliminate two bearings and couplings, and well, such as the conservative marinetake days. This means a project can face avoid alignment problems, producing a industry, that the choice of the rightmajor downtime and potentially simpler and more reliable machine,” technology does indeed lead to lower costscatastrophic financial losses. continues Mäkinen. and greater profitability over the long run,” affirms Jukka-Pekka Mäkinen.More surprisingly, the costs and Unlike DFIG drive trains, PMG designs don’tuncertainties of the entire EPC contract are include slip rings and brushes that are also 4 ways that The Switch lowers the costnot often properly considered, including, for prone to failure. From an engineering of energyinstance, the other components needed to perspective, one fact remains undisputed:support the grid and the operational costs PMG technology is more robust and “We are committed to improving annualof using a DFIG drive train. enduring than DFIG machines. This offers a energy production (AEP) and minimising good shield to owners to protect them from total life cycle costs (TLC), along with cutting back on operational costs. This www.peswind.com 83

TALKING POINTformula works even better with renewables investment costs than conventional The Switch 3 MW units have been tested on– as the cost of wind, wave and tidal, and solutions, but they impress with extremely site and passed all grid code requirements,solar is free,” Mäkinen says. low expenses for operation and even for the latest Chinese regulations. Low maintenance. All products from The Switch flicker, electrical noise emission and THD of1: Increase annual energy production require minimal maintenance and feature a <1.5%, the lowest of any in the entire highly serviceable design to speed up industry, also support the final quality ofHigh availability and great efficiency curves maintenance routines. electricity fed to the grid.make a winning combination to boostannual energy production (AEP). The simplest 3: Extend lifetime of the equipment www.theswitch.comway to increase AEP is to keep turbines orsolar plants up and running to produce a A good purpose-built design, well-selected “Reducing the numberconstant stream of high-quality energy. materials and components, and a carefully of components is planned maintenance program canThe Switch permanent magnet generator lengthen the lifetime of the equipment important, because this(PMG) technology ensures fewer failures substantially. leads to reduced risk.and requires less maintenance whiledelivering superior efficiencies over a wide For example, a well-designed drive The Switch’s PMG driverange of wind speeds. All of The Switch train minimises cogging torque, reducing trains eliminate twoproducts feature a highly serviceable the amount of vibration and lengtheningdesign to minimise the need for the lifetime of all components. Current bearings and couplings,maintenance and increase production time, designs from The Switch have already and avoid alignmentleading to the highest possible availability. been calculated to last longer than problems, producingThe company’s product portfolio covers all 20 years. a simpler and morewind power applications from 1 MW to 8 reliable machine.”MW and higher. 4: Boost the quality of electricity Jukka-Pekka Mäkinen2: Minimise total life cycle costs The success of renewable energy depends on the quality of electricity it feeds into theCutting back on total life cycle costs means grid. The Switch renewable energyscrutinising the expenses associated with solutions have always demonstratedboth the initial capital investment as well as superior grid connection behaviour. Ourthe operating and maintenance costs over full-power converters (FPC) support faultthe lifetime of the equipment. ride-through and fulfil the world’s strictest grid code requirements, including thePermanent magnet generator (PMG) German BDEW 2008.solutions may involve slightly higher84 PES Wind



THINK TANKAdvanced bladepitch systems –insights and trendsThe latest developments in blade pitch technology haveopened new opportunities for wind turbine manufacturers.In this white paper, Mita-Teknik, one of the world’s leadingdesigner and manufacturer of pitch systems, shares itsview of the five key trends of this rapidly evolvingtechnology. It also offers three important insights to keep inmind to make wise pitch system decisions, avoid pitfalls,and choose the right pitch partner.Five key technology trends to watch Although hydraulic systems are extremely couple of years, a number of improvements reliable and have fast pitching have been introduced, helping to run thePreparing for the next energy storage performances, their tendency to leak pitch systems more effectively, the mostrevolution remains a significant downside, if not a deal important being Individual Pitch Control breaker. Indeed, oil leaks are bound to (IPC). By reducing loads, this ground-Energy storage is one of the important occur during the lifetime of the turbine and breaking technology brings the full breadthelements of the pitch system. In the past, all cause significant disorder in the hub. of its benefits over the entire lifetime of theelectrical pitch systems used batteries. Anybody who is familiar with operating wind project.However, over the last few years, the cost wind farms knows that nothing is moreof ultra-capacitors has come down, in large common than the sight of black patches of Let us keep in mind that the pitch andpart due to their broad adoption by the oil and grease leaking down through the turbine control systems together representautomotive industry. Ultra-capacitors, space between the tower and the nacelle. only 4 to 6% of the total turbine costwhich have the major advantage of much The fear of leaks also explains why hybrid depending on the turbine size. This costlonger maintenance intervals, have electric-hydraulic concepts have been can be largely offset thanks to the benefitsprogressively taken on traditional batteries. almost entirely abandoned. of IPC. Not only does IPC lead to moreThey are likely to entirely replace batteries annual production, but this innovation canwithin the next few years as they continue A vast majority of the newer turbine designs also, through the reduction of structuralto be increasingly cost-competitive. rely on electrical pitch systems. loads, extend the lifetime of the assets by Specifically, all machines designed for up to five years. In addition, the reductionBut even as ultra-capacitors are seemingly extreme weather conditions or for offshore,here to stay, energy storage technology is two major areas of future wind powerin such high-speed development that there deployment, are better suited to electricalis no telling what the next innovation will systems that can handle very hot or verybring. Since energy storage systems are cold temperatures and have lowercomponents that wear out relatively quickly, maintenance requirements.they might need to be replaced during thelifetime of the turbine by newer, more Individual pitch control: a genuinecompetitive products. For that reason, technology breakthroughchoosing a pitch system that has theflexibility to open up to different In the wind industry, the pressure to lowertechnologies for energy storage will bring the cost of energy is high. Investors whoyou a long-term advantage. focus exclusively on lowering CAPEX, and increasing the payback rate, too oftenWhy electrical pitch systems will finally choose to ignore the fact that turbinestake over hydraulic solutions deliver their energy over 25 years. However, taking into consideration the total lifecycleOver the last few years, electrical pitch of the assets in order to reduce the cost ofsystems have become affordable, reliable energy is paramount if you are to lower theand safe. For these three reasons they are overall loads on the turbine as well asgradually replacing the traditional hydraulic secure the optimal output. During the lastsystems at an increasing rate.86 PES Wind

THINK TANK“Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor” Picture captionof loads allows for a lighter overall turbine reasons for the relatively slow adoption of especially offshore, poses new challengesdesign with a cheaper bed frame, or smaller IPC is the initial installation cost of the and opportunities for pitch control. Astower. IPC can enable OEMs to increase additional hardware and software needed blades are getting longer, there areblade length while keeping structural loads as well as its higher control complexity. The exposed to increasingly asymmetric windlow. That is a key driver to help bring second reason is the lack of empirical proof forces across the sweep area, creatingturbines to lower wind areas, which is of the long-term indirect financial gains. fierce demands on the pitch system.another key trend in wind farm The last reason is that most pitch systems Downtime, which causes heavy financialdevelopment. in the market today are not fast enough to loses, must be avoided at all cost. Due to utilise IPC. Pitch speed is key to taking full the reduced accessibility of assets at sea,The leading international OEMs understand advantage of the load reduction capabilities minimising maintenance requirements asthe advantages of IPC very well, especially offered by individual pitch control. well as increasing availability have becomethose that are experienced in delivering decisive criteria for the project owner. Forlong-term O&M contracts. Unfortunately, Despite all this, IPC is bound to continue to the same reason, the demand for remotethis approach to long-term asset be steadily integrated into modern turbine troubleshooting is much higher than formanagement is not widespread in the designs, especially for offshore turbine. onshore projects. And the key to achievingindustry yet. Although everybody agrees on all this is redundancy.the benefits of IPC on a theoretical level, Pitch system redundancy will boostonly a limited number of OEMs have already offshore availability Redundancy has been envisaged for aimplemented it in their designs. One of the while, but excessive cost was the main The continuous growth in turbine size, www.peswind.com 87

THINK TANKimpeding issue. Fortunately, offshore replacement with a bigger rotor, along with 360° understanding of wind turbineturbines offer significant economies of an upgraded pitch system. The other controlscale that should allow for the use of exception concerns poorly performing windcostlier, high-performance pitch systems, farms, where defective pitch systems need Secondly, pitch systems are an integratedwhilst still achieving the best overall cost of to be upgraded even if the rest of the part of the overall turbine control system,energy. These systems are set to deliver turbine operates as planned. which means that the continued cohesionoutstanding reliability through redundancy. of its various components must be ensured. Three key insights to make the right Experience has shown that pitch failuresEssentially, the traditional single pitch blade pitch system decisions often come from a lack of understanding ofmotor design will give way to designs how intimately all the turbine controlincorporating multiple smaller pitch motors. Reliability always comes first elements interact with one another.These motors will distribute the loadsaround the pitch bearing while reducing Any company looking to integrate a pitch To get the right pitch system for a turbineslack. Full redundancy will ensure system into its turbine design must, first prototype, a complete set of simulations iscontinued availability even if one part of the and foremost, recognise that the pitch required. This can be achieved by usingsystem fails. system is a central part of the turbine safety “Bladed Models” with a full WTG model system. It has to work seven days a week, simulation. Combined with practice,Pitch motors are heavy components and day in, day out. This is why OEMs should know-how and a lot of field experience,repairs, in the case of breakdowns, are always select partners backed by a strong thorough simulations can determine thecostly. However, if you have two pitch track record in system reliability. optimal solution.motors in working condition, your turbinecan still deliver energy, albeit at a reduced Of course, cost is an important factor, as It will also help to ensure that the turbine isload, until the weather permits the well as reducing structural loads and suited to its operating conditions. In thismaintenance crew to reach the site. extending the turbine lifetime. Nonetheless, instance, an extensive and diversified track unwavering reliability is the very first record and the breadth of feedback data itAs the offshore wind industry develops, consideration to take into account, because generates, is important.pitch control redundancy will play a key role a failing pitch system can outright destroyin keeping very large turbines safe and the asset it was meant to protect. And yet, to build their turbine, some OEMsrunning. quaintly still imagine that they can save One important element is the speed at costs by shopping around for the cheapestMaking sense of pitch systems which the system can pitch blades off-the-shelf components. Lowering theretrofitting according to variations in weather turbine CAPEX becomes the only objective conditions. This is vital when coping with worth pursuing for them. Nonetheless, theyAlthough only one-third of installed turbines extreme weather conditions that will are likely to learn that, for all the money itglobally are currently equipped with active eventually hit your fleet during its 25-year might save upfront, they will remain at thepitch control systems, retrofitting them is lifetime. When exposed to such events, mercy of potential downtime. When failureless straight-forward than it seems. lower quality blade pitch systems may not does occur, the odds are that theTurbines are often too small to justify the be able to cut out of the wind fast enough unfortunate OEMs will be looking for ainvestment. In addition, old models often or as calculated and so damage the entire recognised control expert within days.cannot be fitted with new pitch systems turbine.without upgrading the entire turbine control. Off-the-shelf products can do what they The guarantee for reliability comes from the can do. At the very least, the entire controlThis situation is progressively going to extensive field experience brought by system must be thoroughly tested andchange in the next five to ten years, as thousands of pitch systems designed for assembly must be optimal. Even then, theybigger turbine models are becoming eligible different turbines, operating in different are never going to be as well integrated asfor retrofitting. However, currently only 1.5 climates and different countries. Only a when both pitch and turbine controlto 2 MW turbines associated with a good handful of companies in the global wind systems come from the same supplier.Power Purchase Agreement can justify the industry have acquired such track records.88 PES Wind



THINK TANKThe final advantage resulting from having a A flexible system can adapt more easily as “Achieving optimalsingle technology partner for the combined the turbine design gets upgraded. Being pitch control andcontrol and pitch system is effective flexible means staying clear of systems thattroubleshooting. It enables you to address have a low degree of versatility and minimising structuralall lines of inquiries to a single point of adaptability, such as compact low voltage loads requires acontact. It is especially useful since in most pitch systems, for example. Going withcases, OEM do not know which element of mainstream technology offers high unique set of designthe system is actually causing the failure. sub-components availability over time, and and technology skills.Finally, it will help to resolve issues quickly will ensure you get the best long-term It requires expertise inas well as to maintain a well-optimised benefits out of your pitch control system. load simulation, controlcomplete system. Behind every successful project, there algorithms and windThe benefits of system flexibility is a successful partnership turbine optimisation”Successful pitch control suppliers are, Achieving optimal pitch control andabove all, technology companies that have minimising structural loads requires ademonstrated their ability to stay at the unique set of design and technology skills.peak of innovation over time. The level of It requires expertise in load simulation,flexibility of the selected technology is a key control algorithms and wind turbineparameter to take into account. optimisation. It demands a partner that can deliver a complete design process and runWith regard to turbine development, OEMs all simulations of the turbine to truly delivermust take a long-term view of pitch control, the optimum pitch system that is neededand look for a technology partner that can for prospective field conditions. Above all, itsupply the system they need today, but also demands a partner that can deliver the twinthe system that will be needed in the future. goals of optimal annual production andIndeed, all the lessons learned from the first asset safety.design can be drawn upon to create thenext, more advanced system, instead of For more information visitstarting from scratch with every turbine www.mita-teknik.comprototype.90 PES Wind



TALKING POINT Dutch recipe for Under the Netherlands Energy Agreement for success in Sustainable Growth, the Dutch government has offshore wind set a target of 14% of all energy to be generated from renewable sources by 2020, rising to 16% by The Dutch Government’s offshore wind energy 2023. Offshore wind power is central to achieving programme is making significant waves in the that and, as a country, we are determined to make energy sector, after DONG Energy bid a record-low the Netherlands a leading force in the sector. price for the contract to build and operate the first two projects offered in the country’s five-year tender Under our Government’s plan, there should be programme. That could only happen because of the 4500 MW of offshore wind plant operating in the steps taken by the State in designing an offshore Dutch North Sea by 2023, up from the 1000 MW wind plan and tender system that alleviates risk for currently operating or under construction. the industry, as Ruud de Bruijne, Project Manager, Specifically, the plan will see 3500 MW of new Offshore Wind Energy, Netherlands Enterprise capacity installed across two wind farm zones Agency (RVO.nl) explains. (Borssele and Hollandse Kust), broken down into five 700 MW tender rounds. Critically, the plan92 PES Wind actively fosters a culture of innovation and aims for offshore wind costs to fall by 40% (compared to 2014). Already, that plan is being seen to work. The cost of building and operating the two projects offered up for tender in the first round of the programme is expected to be €2.7 billion cheaper than previously estimated. These two 350 MW projects are located more than 22 km off the coast of the province of Zeeland at Sites I and II of the Borssele Offshore Wind Farm Zone. Overall, there were 38 bids in the public tender to secure the 30-year permit and to build and operate the wind farms along with the associated 15-year “SDE+ subsidy”. Danish offshore wind developer, DONG Energy Borssele 1 B.V., submitted the winning bid with an average of 7.27 euro cent per kilowatt hour. This is 5.1 eurocent less than 12.4 eurocent per kilowatt hour maximum price cap set. There has never been an offshore wind farm built at such low cost in the

TALKING POINT Ruud de Bruijneworld before. Up to now the lowest auction prices fall incrementally with each round in for all projects will be lower than originallyprice for constructing and operating a wind line with our goal to reduce costs. For anticipated, further driving down thefarm was 10.3 eurocent per kilowatt hour, Borssele Sites III and IV, the price cap is levelised cost of electricity from offshorefor a wind farm off the coast of Denmark. 11.975 eurocent per kilowatt hour. For next wind. year’s Hollandse Kust (zuid) tender theOur system, in which companies have to price drops to 10.750 eurocent per kilowatt Recipe for successcompete with each other while the hour, followed by 10.325 and 10.0 eurocentgovernment regulates all conditions for per kilowatt hour for the tenders in 2018 The question many around the world arebuilding the wind farm, has therefore and 2018 respectively (See table below). asking is how have we achieved this andproved to be successful and this reduction enabled DONG to bid a record low price forof cost represents a major breakthrough in Again, based on our experience in the first offshore wind? There are two key factors tothe transition to more sustainable energy. round, we are optimistic that the final cost the success. Firstly, the Netherlands isWe fully expect the costs to come down blessed with some of the most idealfurther as we move forward with furthertenders. Timetable for Dutch offshore wind farm tenders 2015-2019The second tender round in the Dutch Year Wind Farm Zone Project Capacity Price cap (Eurocent/kWh)programme - seeking bids to build and (MW)1 12.400operate Borssele Wind Farm Sites III and IV 2015 - 2016 Borssele (WFS I 700 11.975– closed on 29th September 2016, with the 2016 and II) 11.975final winners expected to be announced by 2017 680the end of the year. Together, these total Borssele (WFS III680 MW (a further 20 MW for innovation and IV) 20projects at Borssele Site IV will also beoffered for tender in the last quarter of Borssele Innovation2017). Meantime, we are already preparing (WFS V)all the necessary documentation and sitesurveys for companies hoping to bid next 2017 Hollandse Kust Zuid 700 10.750year for the first two projects in theHollandse Kust (zuid) region. These will be 2018 Hollandse Kust Zuid 700 10.325350 MW each. Finally, two further tenderrounds are planned in 2018 and 2019, 2019 Hollandse Kust 700 10.000offering up a further 700 MW each, to Noordcomplete the goals of our roadmap to 4500MW of offshore wind. 1 Depending on the type of turbine, an operator is allowed to install 342-380 MW per site, but this presentation assumes a fixed capacity of 350 MW for the sake of simplicity.As with our first tender round, price capsare in place for each planned tender. These Source: Netherlands Enterprise Agency, RVO.nl Table: Price caps in the annual tenders for the Dutch offshore wind programme 2015-2019 www.peswind.com 93

TALKING POINT“Firstly, the Netherlands is blessed with some transmission system operator, takes care ofof the most ideal conditions for offshore wind the offshore grid connections. development in the world” The feedback we have received following the first tender has been positive. We nowconditions for offshore wind development co-developer of offshore wind farms. have a firm idea of the key success factorsin the world: An excellent wind resource, Specifically it is responsible for: and of the lessons to be implemented forrelatively shallow waters and good seabed the future. While the Wind Farm Siteconditions (for both installation and • Site selection Decisions the State produces for eachmaintenance) in the North Sea, well- project tender define the site specificequipped ports and a strong existing • Consenting requirements all companies must abide by,offshore industry and supply chain. and thus offer a certain degree ofSecondly, to actively help drive down costs, • Financial support mechanism - SDE+ standardisation and a level playing field forwe have introduced a stable market operating grant all potential bidders, we have built in a greatframework under which SDE+ subsidies, deal of flexibility for developers too i.e. sizeproject consents and grid connection are • Site investigations and environmental and rating of turbine, foundation choice,streamlined. Together, these factors impact assessments etc. Along with the absence of red tapeenabled DONG and others to develop associated with power projects elsewherestrong plans and submit highly competitive • HV Substations, grid connections and in the world, this allows the developer tobids whereby offshore wind power is associated infrastructure - State TSO optimise project designs.produced as efficiently as possible and TenneT takes on this rolecheaper than ever before. This is further reinforced by the high quality This whole ‘package’ is put to the market site investigations produced. The StateThe Dutch State has effectively removed via the subsidy and permit tender, giving appoints industry leading companies tothe development phase, pre-construction, companies clarity and transparency to conduct them and certify the final resultsburden (in terms of time, cost and risk) from enable them to prepare bids as effectively reports. Industry feedback has confirmedprivate companies, conducting all the as possible. In the tenders, the company that the data made available is more thannecessary site surveys and environmental submitting the lowest bid is awarded a companies would traditionally expect at thisimpact assessments and so forth itself, as permit to build and operate the wind farm stage, enabling them to produce betterwell as responsibility for grid connection. and granted the associated subsidy. informed and thus cheaper designs.Essentially, this makes the Dutch State a Previously, companies had to receive consent before they could compete for the Meantime, the relatively short time between grant and had to install the export cables to when the grant and permit are awarded and shore themselves. Now TenneT, the Dutch construction start means developers can94 PES Wind

TALKING POINTnegotiate competitive prices with suppliers keys to successfully driving down the cost firmly underway and progressing well at the- all projects are expected to be operating of offshore wind while boosting overall Netherlands Enterprise Agency. Thewithin five years of the contract being efficiency and productivity. Hollandse Kust (zuid) Wind Farm Zone isawarded. It is also worth noting that, in located offshore from the province ofoffering two 350 MW projects located close Nonetheless, going forward, all bidders are Zuid-Holland, covering an area of 365to each other in each tender, there is a asked to produce an action plan detailing square kilometres. Four 350 MW windgood balance between: how their project plans, if accepted, will farms are planned for the zone. The full contribute to the local and regional package for Hollandse Kust (zuid) Sites I1. The potential benefits from economy of economy e.g. in terms of job creation, and II will be made available before the end scale (capitalised on by DONG Energy, environmental protection. This plan though of this year, with the tender itself planned for example, in its winning Borssele I and has no formal role in the tender procedure for Q3 2017. The data package of WFS III II bids); and and thus there are no minimum or specific and IV meanwhile will be available in Q1 requirements attached to the request to 2017 (the tender for these sites in planned2. Ensuring the market is fully competitive produce one. Q3 2018). This is subject to approval by the and open to smaller companies. Government of the extension of the Wind Finally, we are also implementing lessons Farm Zone to 10 NM off the coast.Lessons learned drive change learned regarding site investigations. While the industry feedback on our data has been Ruud de Bruijne is Project Manager,Following the tender for Borssele I and II, highly positive, we are expanding the Offshore Wind Energy, Netherlandswe have made some changes to the tender Scope of Work for the geotechnical Enterprise Agency (RVO.nl). Netherlandssystem for Sites III and IV in light of lessons surveys, starting with Hollandse Kust (zuid). Enterprise Agency is part of the Ministrylearned. Our purpose in doing so is to limit the of Economic Affairs and works at the “second phase” geotechnical survey work instigation of Dutch ministries and theIn recent years, there has been a growing needed to be executed by the winner of the European Union.tendency globally for state-led power forthcoming tenders.project auctions to include minimum local For further information please go tocontent mandates. The Government of the Overall, these improvements will hopefullyNetherlands has, however, rejected calls for take the whole package of data we supply www.rvo.nla similar local content requirement to be bidders to a significantly higher standardincluded in its offshore wind programme. and with that help them innovate further to http://offshorewind.rvo.nlWe strongly believe that developers should drive down offshore wind costs.be free to choose their suppliers and thusour system provides them with as much Work on preparing the data package for theflexibility as possible. This is one of the Hollandse Kust (zuid) tender rounds is www.peswind.com 95

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PES ESSENTIALFinancing for wind farms:making consistent useof empirical valuesWords: Thomas Arnold and The recently revised TR6 Technical Independent accredited assessors areThomas Zirngibl, TÜV SÜD Industrie Guideline of the German Public therefore commissioned to verify the yield Association of the Renewable Energy forecast of a planned project. As theseService GmbH Sector (Fördergesellschaft Windenergie forecasts are always based on varying (FGW)) is designed to ensure the provision project-specific facts, figures and data, of reliable yield forecasts. Wind reports their evaluation involves some key based on the Guideline play a critical role questions: What is the quality of the for producing reliable estimates of the available input data? What measurements profitability of a wind-farm project. In the were performed at the site, and over what past, turbines have often been shown to period? Is that period representative, deliver lower energy levels than their allowing conclusions to be drawn reported estimates. The ninth revision of regarding annual yields and forecasts to TR 6 now specifies methods that will help be prepared for twenty years of to produce realistic forecasts of actual operation? Are wind energy turbines on-site wind conditions. already in operation there, and can they be used to validate the model? What Wind speed and direction at the proposed methods of analysis were used in site of a wind farm are critical factors in evaluation? All in all, assessors must determining whether wind farm operation establish whether the information about will be cost-effective over the long term. the project, the future site and its environs Previous practice has shown that is sufficient to allow a realistic yield measurements and evaluations of wind and forecast to be drawn up. weather data may be over-optimistic, favouring the stakeholders’ own interests. New regulations provide for higher At least two wind reports issued by planning certainty third-party organisations are therefore necessary to convince banks and investors The Technical Guideline has addressed these of the profitability of a wind-farm project in issues, specifying normative requirements order to secure financing. and establishing methodological approaches. However, experience from earlier projects www.peswind.com 97

PES ESSENTIALFigure 1 Generally wind speed increases with height above ground. However, the degree of this increase and the operating practices of many windvaries from site to site and depends on a host of factors, including topography (e.g. forested areas). farms have shown that in the past, excessively broad scope for interpretation Figure 1 and individual judgement was left open in many cases – extending to the assessorsWindprofil: ohne Wald Wind profile, unforested area examining and verifying the yield forecasts.Windprofil: Im Wald Wind profile, forested area For example, in some cases variousHöhe über Grund Height above ground level interpretations of specifications wereWindgeschwindigkeit Wind speed possible. The Federation of German Wind Power and Other Renewable Energies (FGW) Figure 2 shows the wind profiles of a site at different seasons. The figure clearly shows several effects, corrected and eliminated this problem by including that wind blows more strongly in winter. The increase in wind speed at higher layers of the issuing a revised version of the Technical atmosphere is likewise more pronounced in winter. Guideline, Part 6, last September, which included important empirical information from98 PES Wind previously realised projects. The Technical Guideline TR 6 has normative status for wind reports. The 9th Revision now contains more clearly worded specifications governing input data as well as new, stricter criteria. For example, the designation of “Wind Report” may only be applied to documents that use the yield data of other wind-energy turbines (“validation turbines”) or wind measurements that are no more than ten kilometres from the planned site. The more complex the topography of the territory, the stricter the requirements. For example, this maximum distance is reduced to only two kilometres in cases where gradients exceed ten per cent or where the altitude between the turbines used for the database and the planned turbine site differs by more than 50 metres. The Technical Guideline revision also clarified the ratio between the hub height applied in actual measurements and the hub height of the planned turbine. Measured data and yield data can now no longer be simply extrapolated and applied to a different height level; instead, valid and scientifically sound methods are required. In the past, the Guideline’s broad scope for individual judgement allowed validation turbines at large distances from the site under examination to be used for calculations. Distances of up to twenty kilometres, or even more in exceptional cases, were common – even though the sites were by no means comparable in terms of topography and wind conditions. This frequently resulted in excessively high yield forecasts. The revisions now introduced to TR 6 have solved this problem and thus provide investors with a significantly higher degree of planning certainty.

PES ESSENTIALFigure 3 shows an example of the frequency distribution of wind directions for an entire year (left) and a and their yields. However, the question isthree-month measurement (right), given in per cent per 30° sector. Where large variations in distribution whether these conditions can beoccur as here, corrective actions are permitted according to FGW TR6 provided the data are filtered extrapolated to the higher atmosphericprimarily from the sectors of the secondary directions of wind while the data from the main directions of layers and, if so, to what extent. Thosewind remain unchanged. Following the corrections, as a minimum requirement the data set must higher layers are where the wind power iscorrespond to an effective measurement period of at least three months to ensure the results are in generated, and as the height of the layersconformity with the FGW requirements and thus valid. increases, wind speeds change in different ways depending on the terrain. The windEfficient generation of valid data TÜV SÜD’s wind-energy experts have profile, which maps wind speed in relation developed a new method that can be to height above ground [Figure 1], isHowever, the project managers, planners applied in large numbers of cases and fulfils site-specific and depends on a wholeand operators are now faced with new all the criteria of the new FGW TR6 series of factors, particularly including thechallenges. What happens if the validation Guideline. Instead of high-cost long-term structure of the terrain at the siteturbines are located at a distance of 11 measurements using a measurement mast, (orography, topography, surface roughnesskilometres from the planned site? Under the the method makes use of light detection and and, where applicable, the trees in a forest)new stricter guideline provisions, the ranging (LIDAR)-based wind measurements as well as parameters of atmosphericmeasurement and operating data from the over shorter periods and incorporates data layering and wind direction.surrounding area previously used to from the German Weather Service. Datacalculate yield forecasts can no longer be from wind farms at greater distances – Seasonal influencesused in analyses, as they no longer comply which are not sufficient in themselves towith distance requirements. In this case, meet the requirements of FGW TR6 – are The last two factors may even displayindividual wind measurements would have complemented by LIDAR measurements at strong variations at one and the same site,to be performed, potentially involving the site, verified and underpinned with as climatic conditions in winter differ fromsix-figure costs. If no comparable validation statistical information. Reliable forecasts can those in summer and wind profiles areturbine is available within the required be drawn up on this basis. closely related to the seasons. Dependingdistance, this method certainly delivers the on the wind farm’s position, wind directionbest and most informative data – but is also Taking repowering as an example, in this may also play a major role; this appliesthe most costly. In this case, then, an situation the wind conditions at the site are particularly if the wind farm is located in theefficient and effective alternative is required largely known because conclusions can be lee of forests, hills or mountain ranges. Anthat is also guaranteed to deliver high- drawn from the data collected over years of evaluation of data collected from windquality and informative data. operation of existing wind energy turbines measurements must describe and consider all these variables and climatic parameters. If long-term measurements are not used, it is essential to compare the collected data with annual or long-term data to provide statistical confirmation. If these aspects are consistently addressed, the required data from the upper atmospheric levels can often be generated within relatively short periods of three to six months. However, the precise duration of measurement cannot be specified in advance, as it depends on the climatic conditions prevailing during the measurement period and the various weather conditions. Meteorology differentiates between stable, neutral and unstable systems of atmospheric layers, which are created by the differences in www.peswind.com 99

PES ESSENTIAL “This new method is still largely unknown in the industry, given the recent publication of the Ninth Revision of TR 6”temperature between near-ground and characteristic for the course of a year. To Long-term measurement series includinghigher layers of air and have significant ensure that results are representative of measurement periods provide information onimpacts on wind systems and wind profiles conditions throughout the year and are the frequency and seasonal distribution of– i.e. wind speeds at various heights. analysable and informative, representative different climatic conditions, and can be put minimum periods must be established for in relation with the LIDAR measurementMapping characteristic seasonal features each layering system. As layering systems and period and continuously compared. When wind directions are not a local phenomenon, comparison of the data shows that these dataFor wind measurements with LIDAR systems, and thus not restricted to the site of map a representative period, measurementthis means that the measurement period must measurement, data from the German Weather can be terminated. This method enables ainclude all possible types of atmospheric Service for the larger region can also be used. reliable wind profile for the site to be drawnlayering in the proportions that are up. When added to the set of data collected from wind turbines with low hub height, this creates a data package that can be used to prepare a yield report in conformity with the FGW requirements. This new method is still largely unknown in the industry, given the recent publication of the Ninth Revision of TR 6. For this reason, empirical values for wind data validation in line with the state of the art are still lacking. It is therefore advisable to rely on support from independent wind experts such as TÜV SÜD, who are familiar with all current requirements and methods in compliance with the Guideline, in order to establish a solid set of data for yield forecasts.Figure 4 shows the frequency distributions of the various atmospheric layering systems for measurement The authorsperiods of one entire year (green) and three months (blue) based on the data in the table. The deviationfrom the annual average is given in the “Difference” column. As stable and neutral layering systems result in Thomas Arnold, Team Leadersimilar wind profiles, the values in the “Difference“ column in classes 1 to 4 and 5 to 6 can be added (last Measurements and Technical Testing forcolumn “Evaluation”). The maximum limit for this total is set at 5%, ensuring that unstable layers are Wind Energy Turbines, TÜV SÜD Industrieadequately considered. Service GmbH Thomas Zirngibl, Team Leader Site Assessment & Technical Due Diligence, TÜV SÜD Industrie Service GmbH TÜV SÜD Industrie Service GmbH, Wind Cert Services, Ludwig-Eckert-Str. 8, 93049 Regensburg, Germany Tel: +49 (0) 941 460212-20 Email: [email protected] www.tuev-sued.de/windenergie1 FGW e. V. – Fördergesellschaft Windenergie und andere erneuerbare Energien: Technische Richtlinien für Windenergie anlagen Teil 6 – Bestimmung von Windpotenzial und Energieerträgen;9th Revised Version of 22 September 2014.100 PES Wind