Sustainability and competitiveness are watchwords of the wind industry in Europe. How turbines and their components are dealt with at the end of their life is key to ensuring both these goals are achieved. Researchers in Germany have created software to help companies choose the most economically intelligent and environmentally friendly end-of-life solutions
The issue:
How to deal with wind turbines at the end of their lives and the best ways to recycle blades and reuse their composites are key questions for the industry
The solution:
A German company has created software to help turbine operators answer questions about repowering, decommissioning and recycling. They are also working on national standards to ensure end-of-life solutions are sustainable. WindEurope, an industry association, is focusing on end-of-life issues and recycling through task forces and events
The quote:
“Rather than having different national solutions, we would prefer to see a more harmonised approach with the same guidelines and best practice shared across the EU.”
In 2021, a 20-year feed-in tariff scheme under the German Renewable Energy Sources Act will end for about 4500 wind turbines and subsidies for another 7500 turbines will be withdrawn by late 2025, raising questions about repowering, decommissioning and recycling. This forthcoming change inspired Jan-Hendrik Piel, co-founder of German start-up Nefino and researcher at the University of Hannover, and his team to focus their minds on how wind operators can find the best economic and environmental end-of-life solutions. Research shows the importance of considering “the overall picture” and comparing all end-of-life options “in an integrated solution”, says Piel. He and colleagues have created software that combines resource, spatial and economic analyses related to extending the lifetime of turbines, repowering and decommissioning. The results show a uniform end-of-funding strategy cannot be applied since turbine-specific aspects, location, type and maintenance costs, and external factors, including electricity spot market prices and tendered feed-in premiums, need to be factored in. From mid-July 2019 this information will be publicly available for the German wind fleet. Piel and his team are now beginning the second phase of their project and from August 2019 will focus on comparing the wind distribution for which a turbine has been designed and the real distribution experienced by a turbine over its lifetime. “From this it will be possible to get an idea of whether the turbine could be operated for another three, five or ten years,” says Piel. The researchers are also looking at the most efficient ways to dismantle and recycle turbines. In a paper published at the end of 2018, they underline how today, onshore wind turbines are generally dismantled on-site. “The rotor blades are cracked, the tower segments are separated and the nacelle is cut into smaller pieces,” they write. “This undistributed dismantling […] is very time-consuming, inefficient and implies ecological and economic risks.” The researchers estimate the dismantling of a single wind turbine can take around two weeks and entail costs of more than €130,000, depending on location and type. On-site dismantling can also delay the construction of new turbines in cases of repowering, contributing to lost revenues, they find.
Reverse supply chain
A better economic and environmental solution would be to transport partly dismantled wind turbines to specialised sites, say the researchers. This would also permit better refining and potentially higher revenues from selling raw materials, they suggest, though acknowledge that setting up such sites and the transport of large-scale components can be costly. To try to solve this conundrum, the researchers have created a computer model showing optimal dismantling options and prime locations for dismantling sites. The methodology, based on a case-study of a wind farm in Northern Germany which dismantled six turbines, found companies can reduce costs by over a third by opting for a “cost-efficient dismantling network instead of undistributed dismantling entirely on-site”. This applies for the rotor blades and the nacelle and, with some limitations, for the tower. The foundation, however, should still be dismantled entirely on-site, concluded the study. The researchers advocate creating a network “built like a reverse supply chain, that includes wind turbine locations, dismantling factories and disposal centres” to ensure everything happens in the right place at the right time. In summer 2019, Piel and his team will publish a case study of 56 turbines in the region of Osnabruck, Northern Germany, which, says Piel, confirms this approach.
Regulation and standards
The researchers would also like to see “regulation and standards” to ensure ageing wind turbines are dealt with in a more coherent manner. “With companies from the wind industry and the recycling and resource management sector, we are working on guidelines for the dismantling of wind turbines in Germany, which could also help accelerate the implementation of a European standard,” says Martin Westbomke from RDRWind, an industry association. The dismantling and recycling of blades and blade material and finding more secondary markets for components once they have been broken down are the main issues still to be resolved, states Westbomke. Standards and regulation creating a “closed loop supply chain” in the wind industry could help, he says. “We need to learn from established industries such as the car industry.” WindEurope, an EU industry lobby group, is leading the charge to answer these questions at a European level. In the next couple of months it will create a task force on dismantling and decommissioning to “gather state of the art practices from around the EU that will form the basis for guidelines”, says Mihaela Dragan, sustainability analyst at WindEurope. The task force will include national wind energy associations, turbine producers and waste management companies, and build on the cross-sectoral collaboration on recycling wind turbine blades already ongoing with the European Chemical Industry Council and the European Composites Industry Association, she adds. WindEurope will also hold its first ofend-of-life issues and strategies seminar in Leuven, Belgium in September 2019 where industry and academic experts can discuss issues related to “lifetime extension, decommissioning and repowering from technical, sustainability and economic angles”, says Dragan.
Cost effective
As for the methodology drawn up by Piel and colleagues, Dragan says it is “interesting. But we need more time to fully understand how it works and to consult with our members”. She believes it is premature to discuss an EU-wide law on end-of-life solutions at this stage. “Rather than having different national solutions, we would prefer to see a more harmonised approach with the same guidelines and best practice shared across the EU. This is necessary before we start discussing EU standards and regulation.” Dragan also emphasises the importance of finding “the most cost effective solutions”. She states: “We are a mainstream technology and we want to be sustainable, but also remain competitive. Other more mature industries, such as the aviation or marine sector, also have the challenge of dealing with composites and have not found solutions.” Nonetheless, she cites various promising projects. In Germany and France, resins from wind turbine blades are being used in the cement industry since they have a high energy content, which can be recovered to use instead of fuel, while the mineral fraction can replace virgin raw material. In Spain, Reciclalia is looking at recycling wind turbine blades through pyrolysis which allows long fibres to be recuperated. “The challenge is to find secondary applications that can use the recovered material,” says Dragan. “Virgin glass fibres are very cheap so it is difficult to make a business case out of recovering glass fibres, but there is a lot of attention on finding solutions.” Jan-Hendrik Piel presented his research at the WindEurope 2019 Conference in Bilbao, Spain in April.
Writer: Philippa Nuttall Jones