G NER Y SE E CU O R T I A T Y N NATO ENERGY SECURITY C E CENTRE OF EXCELLENCE E C N T N R E E LL OF EXCE ENERGY HIGHLIGHTS ENERGY HIGHLIGHTS 1 Content 7 Introduction 11 Chapter 1 – Wind Energy Systems and Technologies 25 Chapter 2 – Radar Systems and Wind Farms 36 Chapter 3 – Wind Farms Interference Mitigation 46 Chapter 4 – Environmental and societal impacts of wind energy 58 Chapter 5 – Wind Farms and Noise 67 Chapter 6 – Energy Storage and Wind Power 74 Chapter 7 – Case Studies 84 Conclusions 86 A Way Forward 87 Bibliography This is a product of the NATO Energy Security Centre of Excellence (NATO ENSEC COE). It is produced for NATO, NATO member countries, NATO partners, related private and public institutions and related individuals. It does not represent the opinions or policies of NATO or NATO ENSEC COE. The views presented in the articles are those of the authors alone. © All rights reserved by the NATO ENSEC COE. Articles may not be copied, reproduced, distributed or publicly displayed without reference to the NATO ENSEC COE and the respective publication. 2 ENERGY HIGHLIGHTS ENERGY HIGHLIGHTS 3 Role of windfarms for national grids – challenges, risks, and chances for energy security by Ms Marju Kõrts ACKNOWLEDGEMENTS EXECUTIVE SUMMARY AND KEY have arisen in other countries wher wind power RECOMMENDATIONS The author would like to acknowledge the work and insights of the people who contributed to this is expanding. study either via the conducted interviews or their fellowship at the NATO Energy Security Center of apid growth of wind energy worldwide Excellence in summer and autumn 2020. I would like to especially thank the following people: has led to the increased installation of There is no fundamental physical constraint that wind farms that are more efficient, pow- prohibits the accurate detection of aircraft and Jan Schlüter erful, and have taller wind turbines. As weather patterns around wind farms. On the Max Planck Institute, Germany (Chapter 1) Rwind development continues to grow and expand other hand, the aging radar infrastructure signifi- to new areas of the country, so does the possibil- cantly increases the challenge of distinguishing Johann Seebass ity that some turbines would be located within wind farm signatures from airplanes or weather. Max Planck Institute, Germany (Chapter 1) the line of sight of radar systems. This could have On one hand, wind turbines are getting bigger potential effect on national flight safety, weather and more powerful to harvest more energy, on Dujon Goncalves – Collins forecasting, and national defence radar opera- the other hand there will be more challenges for Vattenfall Wind Power, United Kingdom (UK Case Study) tions. Wind turbines can cause radar interference the defence radars to cope with this situation. whereby the blades appear as „clutter“ on radar Thus, the probability for wind development to screens and can be mistaken for aircraft. Plans present conflicts with radar missions related to to set ambitious renewable energy targets have air traffic control, weather forecasting, national been impacted by the objections of the Minis- security and defence is also likely to increase, as tries of Defence that wind turbines interfere with is the potential severity of those conflicts. Cer- military radars. In a number of cases the military tainly, the positioning of aviation infrastructures has claimed that the wind farms are an encroach- such as airports and helipads, and wind infra- ment on military radar facilities, and have stalled structures such as wind farms and turbines, will construction on the wind farm. Similar problems continue to be a challenge. Therefore, a justified by Ms Marju Kõrts Ms Marju Kõrts is an Estonian career diplomat who has hold several positions at the Estonian Ministry of Foreign Affairs. She graduated with her Masters degree in political science at Tartu University in Estonia. With the current function as the Estonian Subject Matter Expert at the Research and Lessons Learned Division of the NATO Energy Security Center of Excellence in Vilnius she focusses on the new energy technologies. At present she is conducting a research study: “Offshore Wind Farms – Challenges, risks and opportunities for building more resilient national energy system. E-mail: [email protected] 4 ENERGY HIGHLIGHTS ENERGY HIGHLIGHTS 5 question can be posed whether wind farms can terference are required. Although a great deal is ties, there is still quite a lot of resistance to the 2. The evaluation system should include a cost co-exist with radar installations? now understood about the potential effects of wind developments due to the environmental benefit analysis of mitigation strategies. Once wind turbines on many types of radar as well as and societal reasons. The local residents often the potential for different mitigation measures Progress forward requires the development of their impacts on the missions those radars sup- claim about the noise or light pollution. Noise are understood, there is no hurdle for estab- mitigation measures, and quantitative evaluation port, nevertheless new issues are likely to arise. emissions may be heard, felt, or sensed. Some of lishing regulations that are simple to under- tools and metrics to determine when a wind farm One class of mitigation solutions is the augmen- them are in the audible range, the others are in stand and simple to implement, with a single poses a sufficient threat to a radar installation for tation or „infill“ radars. Where a potential siting the low frequency range and those may be heard. government entity taking responsibility for corrective action to be taken. Mitigation measures conflict manifests itself, an impacted legacy ra- There are mainly two sources of noise in a wind overseeing the process. may include modification to wind farms (such as dar’s performance loss may be restored by plac- turbine: aerodynamic that is generated by the methods to reduce radar cross-section; and telem- ing one of these infill radars, with advanced clut- motion of air around the blades, and mechanical INTRODUCTION etry from wind farms to radar), as well as modifi- ter suppression techniques, closer to wind farms caused by the motion of the mechanical and elec- By the end of this year European countries are cations to radar (such as improvements in process- to restore the lost surveillance coverage. Anoth- trical components. Light pollution occurs in the due to deliver on their 2020 renewable energy ing; radar design modifications; radar replacement; er approach is to improve the wind turbine inter- form of strobing (also known as „shadowflicker- targets and will start implementing their 2030 and the use of gap fillers in radar coverage). ference mitigation capabilities of existing radars ing“) or from aircraft warning lights mounted on National Energy & Climate Plans (NECPs) to- through signal processing, software upgrades and the towers. Improving warning lights to lit up the wards the 32% renewable energy goal. The de- Establishing the optimal mitigation strategy minor hardware modifications, which are likely wind turbine only when there is an actual aircraft pletion of conventional energy sources and the for a specific case requires in-depth analysis of to result in lower-cost solutions to wide-scale to warn in its vicinity is not a new idea, and indi- rising greenhouse gas emissions are fueling the the particular site. However the most common deployment of short-range infill radar systems. vidual tests to achieve this has been successfully adoption of renewable energy sources across technological solutions currently employed also New design and operational methods for future carried out in the past. Due to the large number the world. Wind is one of the most abundant include blanking where radar returns within the wind turbines deployed in close proximity to vi- of wind farms, Germany is especially interested and efficient sources of power generation. Coun- wind farm boundary are not shown on the radar tal radar assets could reduce radar impacts either in this issue and is at present implementing new tries such as Denmark, Spain, Germany, and the screen. This eliminates the issue of wind turbines independently or in conjunction with mitigation regulations to enforce an on-demand warning United Kingdom produce more than 10% of their showing up as targets on a radar screen, but it measures applied at the impacted radar systems. light system as requirement for wind farms. power from wind energy. also means that an aircraft overflying the wind farm will not be displayed. In the United King- Beyond radar-absorbing materials, there are ad- All in all, wind energy developments can also be Several studies, e.g “Wind Energy in Europe: Out- dom for example, the industry together with the ditional at-the-turbine solutions, e.g. reduced seen as an opportunity and not as a problem as look to 2022” prepared by WindEurope reinforce aviation sector has also looked at changing the radar impact lightning protection systems, ma- the experience of Belgium shows. Namely, with the idea that wind energy will play a key role in turbine design, but that is not always possible or terials, and structures are especially important the use of new generation mine-sweepers that the necessary energy transition to meet the chal- it has not always given the desired results. for over-the-horizon radar systems. New opera- also rely on drone technology, the offshore wind lenges of climate change and produce clean en- tional methods in which data from individual tur- farms matrix can be used for the logistical sup- ergy. The study “Utility of the Future”1 by Mas- Collaboration is the key as the wind industry rec- bines are combined with data in real time could port of this network (e.g. recharging the drones’ sachusetts Institute of Technology points out ognizes the need for technical solutions so that also be explored as a potential mitigation meth- batteries).