By Michal Pati
Climate change is the prime driver behind the move away from burning fossil fuels to renewable technologies. The UN’s Climate Change report states that limiting warming to 1,5°C will require cutting CO2 emissions to zero by 2050 (1). Deployment of renewables along with the decarbonisation of economy and improved energy efficiency can reduce energy related carbon emissions by 90%, and thus help in achieving carbon neutrality (2).
In 2020, the global cumulative installed wind power capacity amounted to 743 GW, (3) compared to only 14 GW at the end of 1999 (4). In order to reach the goals of the Paris Agreement, the world will need to accelerate the pace of installation of wind power plants by adding four times more onshore wind power capacity (200 GW), and ten times more offshore wind power capacity (45 GW) to the grid every year in the coming 20 years (in comparison with the 2018 figures) (5).
However, modern wind turbines are designed to operate for 20 – 25 years (6). The expensive and complex decommissioning of oil and gas production facilities in the North Sea gives rise to a question: have we figured out what will happen to wind power plants at the end of their lifetime?
There are three possible courses of action once a turbine reaches the end of its planned service life: (1) a lifetime assessment can be produced to prolong its life; (2) it can be repowered; or (3) dismantled as part of the decommissioning process.
(1) Life extension
Wind farm operators are looking into options for extending the lifespan of their ageing assets. The life of the turbine can be extended by maintenance and regular monitoring. The possibility and costs of extending a wind turbine’s operation are determined through the lifetime assessment consisting of analytical and practical evaluations (7). The assessment considers structural stability of the turbine and environmental conditions in combination with findings gathered during the on-site inspection. The engineers need to calculate the amount of pressure to which the asset was exposed during its operational lifetime and compare it with the expanded lifespan of the asset (8). As a result, this report will determine whether any components need to be replaced for the turbine to continue its operation.
Life extension reduces the asset’s lifetime levelized cost of electricity, and thus maximises revenues generated. In addition, the life extension involving the replacement of only certain components requires lower investment in comparison with the full repowering (9). Rubén Ruiz de Gordejuela, Chief Technology Officer at Spain’s Nabla Wind Power, a life extension service provider, says that the average cost for extending the life of a turbine is around 100,000 euros/MW, while repowering costs on average 1 million/MW (10).
(2) Repowering
Although life extension offers numerous benefits, the greatest revenue potential offers repowering. It entails replacing wind turbines with new larger and more efficient ones within the same wind farm using the infrastructure developed for the original project. CEO of Wind Europe Giles Dickson says that with the current technologies, repowering can reduce the number of turbines by a third while increasing the electricity output by three times. (11)
There are several reasons why wind farm operators would choose to repower their turbines. Firstly, some of the best sites for wind developments have already been developed, (12) and therefore operators aim at increasing the profitability of their brownfield projects. Secondly, wind farm developers often face opposition from residents, and thus it is easier to repower sites, where the developer has already established connections with the local community. Thirdly, projects planners usually consider potential repowering or life extension for the wind farms at the beginning of the process. For example, leases for the seabed, on which offshore wind farms have been constructed, are granted for 40-50 years, instead of 20-25 years.
(3) Decommissioning & Dismantling
In Europe, there are currently 34,000 onshore wind turbines older than 15 years capable of producing 34 GW of electricity (13). Considering the volume of onshore and offshore wind power capacity added in the previous decade and the massive investments in renewables in the coming years, decommissioning is becoming an increasingly important topic. Especially, if environmental sustainability is to be at the heart of the clean energy transition. Decommissioning involves removing the erected structures and returning the site to its original condition. Ms Topham and Mr McMillan argue that offshore wind farms need to be designed with the decommissioning phase in mind – for example, by making the structures lighter and avoiding deep foundations (14). Besides lowering the costs of removing structures from the sea, detailed planning could also provide an opportunity to improve the recyclability of blades.
Wind Europe states that 85 – 90% of a dismantled wind turbine can be recycled (15). The biggest obstacle to recycling pose blades, which are made of composite materials being more difficult to recycle. Those usually end up in the landfill (16). Considering that 300 and 1,600 wind turbines will need to be decommissioned in the UK by 2025 and 2030 respectively, (17) it is essential to invest in new materials strengthening the construction of wind farms while creating a dynamic market for recycling their blades.
At present, investors and governments concentrate on expanding energy capacity, improving installations and developing technologies enabling wind turbines to be larger, to produce more electrical power and to be constructed cheaper. Similarly, the early oil and gas projects in the North Sea did not always consider how the project would be decommissioned. That caused numerous logistical and technical difficulties in dismantling, and consequently a rise in the costs of the process. Offshore and onshore wind farms have a huge potential for the world transitioning to the net zero carbon economy. However, we need to put larger emphasis on the way wind farms are being designed, so they can be operated for longer, dismantled easily and their components recycled properly.
References
(1) The Intergovernmental Panel on Climate Change, ‘Climate Change 2021: The Physical Science Basis’ (2021) <https://www.ipcc.ch/sr15/> accessed 15 August 2021.
(2) International Renewable Energy Agency, ‘Future of Wind: Deployment, investment, technology, grid integration and socio-economic aspects’ (2019) <https://irena.org/-
/media/Files/IRENA/Agency/Publication/2019/Oct/IRENA_Future_of_wind_2019_summ_EN.PDF> accessed 17 August 2021.
(3) Global Wind Energy Council, ‘Global Wind Report 2021’ (2021) <https://gwec.net/global-wind-report-2021/> accessed 17 August 2021.
(4) REVE, ‘The wind power market expanded substantially in the 2000s’ (2011)
<https://www.evwind.es/2011/06/27/the-wind-power-market-expanded-substantially-in-the-2000s/12167> accessed 18 August 2021.
(5) International Renewable Energy Agency, ‘Future of Wind: Deployment, investment, technology, grid integration and socio-economic aspects’ (2019) <https://irena.org/-
/media/Files/IRENA/Agency/Publication/2019/Oct/IRENA_Future_of_wind_2019_summ_EN.PDF> accessed 17 August 2021.
(6) TWI, ‘How Long Do Wind Turbines Last? Can Their Lifetime Be Extended?’ <https://www.twi global.com/technical-knowledge/faqs/how-long-do-wind-turbines-last> accessed 19 August 2021.
(7) Benjamin Pakenham, Anna Ermakova, Ali Mehmanparast, ‘A Review of Life Extension Strategies for Offshore Wind Farms Using Techno-Economic Assessments’ [2021] 14, 1936 Energies.
(8) Christian Schumacher and Florian Weber, ‘How to extend the lifetime of wind turbines’ (Renewable Energy World, 20 September 2019)
<https://www.renewableenergyworld.com/om/how-to-extend-the-lifetime-of-wind-turbines/#gref> accessed 16 August 2021.
(9) Paul Dvorak, ‘An owner’s guide to wind turbine lifetime extensions’ (Windpower Engineering Development, 29 September 2017)
<https://www.windpowerengineering.com/owners-guide-wind-turbine-lifetime-extensions/> accessed 16 August 2021.
(10) Jason Deign, ‘European tariff cuts support cost-saving lifespan extensions’ (Reuters Events – Renewables, Janurary 18 2016) <https://www.reutersevents.com/renewables/wind-energy-update/european-tariff-cuts support-cost-saving-lifespan-extensions> accessed 18 August 2021.
(11) Wind Europe, ‘What happens when wind turbines get old? New Industry Guidance Document for dismantling and decommissioning’ (2020) <https://windeurope.org/newsroom/press-releases/what-happens-when-wind turbines-get-old-new-industry-guidance-document-for-dismantling-and-decommissioning/> accessed 19 August 2021.
(12) Office of Energy Efficiency & Renewable Energy, ‘Wind Repowering Helps Set the Stage for Energy Transition’ (2021) <https://www.energy.gov/eere/wind/articles/wind-repowering-helps-set-stage-energy transition> accessed 18 August 2021.
(13) Wind Europe, ‘Decommissioning of Onshore Wind Turbines’ (2020) <https://windeurope.org/intelligence platform/product/decommissioning-of-onshore-wind-turbines/> accessed 15 August 2021.
(14) Eva Topham, David McMillan, ‘Sustainable decommissioning of an offshore wind farm’, (2017) 102 Renewable Energy 470.
(15) Wind Europe, ‘What happens when wind turbines get old? New Industry Guidance Document for dismantling and decommissioning’ (2020) <https://windeurope.org/newsroom/press-releases/what-happens-when-wind turbines-get-old-new-industry-guidance-document-for-dismantling-and-decommissioning/> accessed 19 August 2021.
(16) Sarah Golden, ‘The Circular Economy Meets Decommissioned Wind Turbine Blades’ (GreenBiz, 11 June 2021) <https://www.greenbiz.com/article/circular-economy-meets-decommissioned-wind-turbine-blades> accessed 16 August 2021.
(17) Sam Wood, ‘Ageing offshore wind turbines could stunt the growth of renewable energy sector’ (University of Kent News Centre, 15 February 2021) <https://www.kent.ac.uk/news/science/27849/ageing-offshore-wind turbines-could-stunt-the-growth-of-renewable-energy-sector> accessed 19 August 2021.
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