By Angeliki Spyroudi, Senior Strategy Analyst at ORE Catapult
Over the past few weeks, experts at ORE Catapult have been exploring different scenarios in adopting a circular economy within offshore wind. We’ve spoken at length about the economic benefits of investing in such a strategy, with our latest report suggesting that 20,000 additional jobs could be added to the sector by 2030.
The “linear” approach to product development has been the norm for decades. However, an increase in demand and the scarcity of natural resources have given rise to a more “circular” model, with the reuse and recycling of valuable materials to minimise waste.
With 1.5GW of offshore wind estimated to be decommissioned by 2030 globally and 13GW by 2040, the need for efficient recycling measures becomes even more important as the industry and turbine sizes grow.
As well as the financial return, each end-of-life management strategy’s environmental impact should also influence the final decision. It’s important to understand that with any manufacturing process – even green manufacturing – some carbon emissions will be produced throughout the final product’s lifetime. That being said, its operations may offset or even reduce the levels of carbon emitted.
Wind power already has one of the lowest carbon footprints compared to other energy sources and produces zero-emission electricity, but we can always do more. Our estimations showed that carbon savings from offshore wind electricity generation, compared to the same electricity produced from natural gas, is on average 143 ktCO2e per wind turbine – that’s equivalent to the CO2e emitted from approximately 70,000 UK petrol cars in a year. By adopting a more sustainable approach, our analysis shows that on average, recycling turbines at the end of their lifetimes can save at least 35% of carbon emissions equivalent per kWh when compared to manufacturing of components using primary raw materials.
However, recycling is not the only option available to the wind industry when implementing a circular economy. It’s fundamental to adopt a proactive approach to end-of-life management in offshore wind as early as the design phase, establishing a sustainable framework.
Decommissioning is currently the default option, but extending the product’s life cycle and repowering (upgrading parts of the old asset) is also being seriously considered. These options can extend the use of the existing assets, often offering higher yields, lower maintenance costs and environmental benefits in delaying and preventing disposal. For these strategies, carbon emissions are present in the turbine and also the operation and maintenance vessels.
To illustrate, I have estimated the value of the carbon footprint of vessels used for decommissioning, extending the lifetime and repowering for a representative UK windfarm with a 25-year lifecycle and charted the results below. As expected, life extension showed the lowest emissions as inspection and crew transfer vessels are only required to conduct minor repairs.
However, the carbon emissions from adopting these end-of-life approaches are minimal compared to the carbon saved from the operation of the wind farm. This is demonstrated further by the 10MW larger turbines saving an extra 110 MtCO2e per year when a wind farm is repowered, compared to the same electricity produced from a conventional natural gas plant.
When considering a wind turbine’s full life cycle, current carbon emissions estimates are around 0.011 kgCO2e/kWh  – less than 2.5% of the estimated life cycle emissions from a natural gas plant. Extending the life of existing wind farms either through repowering or delay of decommissioning and recycling of materials can lead to even higher levels of clean electricity generation from the same windfarm with a lower amount of primary resources spent per kWh generated.
Windfarm life extension means more clean electricity and carbon saving using the same assets, giving a further saving of 1.45 MtCO2e for these extra 10 years of electricity generation. Repowering for 25 years at the end of the initial useful life by upgrading the existing assets with 10MW rated turbines (350MW) can increase savings compared to the base case of 6.40 MtCO2e (0.26 MtCO2e per year).
To summarise, moving from a linear to circular economy will help to reduce the carbon footprint of the offshore wind industry as well as provide immense economic opportunities for the UK. By recycling turbines at the end of their lifetime, it can reduce CO2e emissions by 35% compared with manufacturing components entirely from primary raw materials. Recycling is not the only approach that can reduce the industry’s carbon footprint however, with extending the lifetime of wind farms through proactive O&M and repowering also deemed appropriate avenues to explore further.
To learn more about the carbon emissions from different end-of-life strategies, you can read my latest Analysis and Insight papers on our website: Carbon footprint of offshore wind farm components and End-of-life planning in offshore wind. I would like to thank Zero Waste Scotland for their contributions to the papers.
 NREL (2013) Wind LCA Harmonization. Available here >