Dr Anne Velenturf (Research Impact Fellow in Circular Economy and Offshore Wind at the University of Leeds) explores a framework for offshore wind turbines in the circular economy.
A majestic turbine streaks the blue sky. A warm breeze powers our homes. A promise of change is in the air. This is the image that is often depicted with inspirational pieces on circular economy.
How ironic is it then that most infrastructure for wind power is not designed with a circular economy in mind at all! A significant proportion of onshore wind turbines will reach the end of their 20-25 years designed life in the next 5 years. In some countries this covers more than half of the installed capacity[i]. The first wave of offshore wind turbines will reach the same point within the next 10 years[ii]. Estimates are that at least 22GW will reach end of use by 2024[iii]. In short, there is a growing need for end of use solutions for wind energy infrastructure.
The wind sector has much to gain from the integration of circular economy strategies. About 70-80% of the environmental impact of wind turbine manufacturing originates from material extraction and processing[iv][v], highlighting the importance to maximise resource productivity throughout the lifecycle of a wind farm[vi]. But end of use management of wind infrastructure is a “fragile point” in the environmental performance[vii].
Estimates are that 80-90% of the weight of wind turbines can be recycled[viii]. However, evidence of actual recycling rates is thin on the ground. Moreover, recycling ranks relatively low in the hierarchy of circular economy strategies because a) other strategies such as repair, reuse and remanufacturing generally have a better sustainability potential and b) recycling can be energy and water intensive while being associated with losses in material quality and volumes that then have to be substituted in new production cycles. The biggest concerns are for the recycling of blades due to a lack of sustainable solutions to recover the composites that they are made of.
University of Leeds research showed that offshore wind farms are not generally developed with a circular economy in mind and fail to take a long-term and joined up perspective regarding resource extraction, use and end of use management[ix]. A new EPSRC project, co-funded by the Offshore Renewable Energy Catapult, the Department for International Trade and the University of Leeds, aims to change that. To start, a framework has been outlined to integrate circular economy into the design, operation and end of use management of offshore wind infrastructure (see figure).
The framework proposes a circular economy for offshore wind consisting of 15 elements, in order of priority to optimise values for a sustainable circular economy:
- Design for circularity: proactive design to maximise the sustainability potential of a circular economy with a balanced mix of all the strategies listed:
- Dematerialisation: reduced resource use through, for example, shape optimisation and using alternative materials.
- Waste reduction: eliminating waste from production through design or by putting wastes and by-products to use through industrial symbiosis.
- Repair and maintenance: preventative, planned or ad hoc inspection/ servicing tasks, which may involve repairs to restore a component to a good working condition[x].
- Lifetime extension: wind farms kept in use beyond the designed service life of 20-25 years[xi].
- Component reuse and refurbishing: components are used again for the same function which may involve various actions to prepare for reuse (checking, cleaning, repairing, refurbishing)[xii].
- Remanufacture: components are sorted, selected, disassembled, cleaned, inspected and repaired/ replaced before being reassembled and tested to function as good as new or better[xiii].
- Disassembly: a key step to take components apart to enable repair, reuse, upgrading, remanufacturing and recycling, to be considered at the design stage[xiv].
- Repowering: extend wind farms’ service life by replacing some or all wind turbine components[xv].
- Decommissioning: de-energising, dismantling and removal of some or all parts of a wind farm, followed by site restoration and monitoring[xvi].
- Site recovery: returning a site to a similar state as before the wind farm development.
- Recycle materials: the collection and preparation of wastes into materials that can re-enter production, and the reprocessing of recyclates into new components.
- Landfill and controlled storage: storage and compaction of components and materials into defined cells that prevent pollutants from entering the surrounding environment, often combined with resource and energy recovery[xvii].
- Re-mine: recovery of materials from “Anthropogenic Ores” such as the industrial, municipal, metallurgical, and mining wastes that people have entrusted into geological storage[xviii].
- Energy recovery: recovery of the energetic input invested into the preparation of materials and components.
This is a draft framework and your input is very welcome. Are there any circular economy strategies missing? Or are there too many sides to it and would you like to propose an alternative structure? Are all the important connections between the various strategies made in the figure? Do you agree with the order of priorities of circular economy strategies? What are the blockers and enablers in realising a circular economy in offshore wind? What role could the resources sector play alongside offshore wind actors in realising a sustainable circular economy? Are there any quick wins? What matching expertise could you bring? What are the business opportunities?
Later this year a workshop will be held aiming to bring together the resources and offshore wind sectors to discuss what a circular economy for offshore wind could look like, what roles the different sectors could play in it, and start conversations on specific solutions for blade recycling to solve short term challenges with emerging composite wastes.
[ii] Jensen, P.D., Purnell, P., Velenturf, A.P.M. 2020. Highlighting the Need to Embed Circular Economy in Low Carbon Infrastructure Decommissioning: The Case of Offshore Wind. Sustainable Production and Consumption, Vol. 24: 266-280. https://www.sciencedirect.com/science/article/pii/S2352550920304413
[iii] Ibid i.
[iv] Jensen, J.P., 2019. Evaluating the environmental impacts of recycling wind turbines. Wind Energy 22, 316-326; Jensen (2019)
[v] Stamford, L., Azapagic, A., 2012. Life cycle sustainability assessment of electricity options for the UK. International Journal of Energy Research 36, 1263-1290.
[vi] Ibid ii.
[vii] Pego, A.C., 2019. The Portuguese Offshore Energy SWOT Analysis, Journal of Physics: Conference Series, 1 ed; EU (2015) Energy sectors and the implementation of the Maritime Spatial Planning Directive.
[viii] Ibid iv.
[ix] Ibid ii.
[x] Reike, D., Vermeulen, W.J.V., Witjes, S., 2018. The circular economy: New or Refurbished as CE 3.0? — Exploring Controversies in the Conceptualization of the Circular Economy through a Focus on History and Resource Value Retention Options. Resources, Conservation and Recycling 135, 246-264; den Hollander, M.C., Bakker, C.A., Hultink, E.J., 2017. Product Design in a Circular Economy: Development of a Typology of Key Concepts and Terms. Journal of Industrial Ecology 21, 517-525; Bocken, N.M.P., de Pauw, I., Bakker, C., van der Grinten, B., 2016. Product design and business model strategies for a circular economy. Journal of Industrial and Production Engineering 33, 308-320.
[xi] Topham, E., Gonzalez, E., McMillan, D., João, E., 2019. Challenges of decommissioning offshore wind farms: Overview of the European experience, Journal of Physics: Conference Series, 1 ed.
[xii] DEFRA. 2011. Guidance on applying the Waste Hierarchy; den Hollander, M.C., Bakker, C.A., Hultink, E.J., 2017. Product Design in a Circular Economy: Development of a Typology of Key Concepts and Terms. Journal of Industrial Ecology 21, 517-525; EU, E.U., 2008. Directive 2008/98/EC of the European Parliament and of the Council of 19 November 2008 on waste and repealing certain Directives (Text with EEA relevance).
[xiii] Lieder, M., Rashid, A., 2016. Towards circular economy implementation: A comprehensive review in context of manufacturing industry. Journal of Cleaner Production 115, 36-51; Priyono, A., Ijomah, W., Bititci, U.S., 2016. Disassembly for remanufacturing: A systematic literature review, new model development and future research needs. Journal of Industrial Engineering and Management 9, 899-932.
[xiv] Kerin, M., Pham, D.T., 2019. A review of emerging industry 4.0 technologies in remanufacturing. Journal of Cleaner Production 237; Priyono, A., Ijomah, W.L., Bititci, U.S., 2015. Strategic operations framework for disassembly in remanufacturing. Journal of Remanufacturing 5.
[xv] Bezbradica, M., Kerkvliet, H., Borbolla, I.M., Lehtimaki, P., 2016. Introducing multi-criteria decision analysis for wind farm repowering: A case study on Gotland, 1st International Conference on Multidisciplinary Engineering Design Optimization, MEDO 2016; Hou, P., Enevoldsen, P., Hu, W., Chen, C., Chen, Z., 2017. Offshore wind farm repowering optimization. Applied Energy 208, 834-844; Luengo, M.M., Kolios, A., 2015. Failure mode identification and end of life scenarios of offshore wind turbines: A review. Energies 8, 8339-8354.
[xvi] Welstead, J., Hirst, R., Keogh, D., G., R., Bainsfair, R., 2013. Research and guidance on restoration and decommissioning of onshore wind farms. Scottish Natural Heritage Commissioned Report No. 591; Smith, G., Lamont, G., 2017. Decommissioning of Offshore Wind Installations – What we can learn, Offshore Wind Energy 2017, London, UK; Hou, P., Enevoldsen, P., Hu, W., Chen, C., Chen, Z., 2017. Offshore wind farm repowering optimization. Applied Energy 208, 834-844.
[xvii] Townsend, T.G., Powell, J., Jain, P., Xu, Q., Tolaymat, T., Reinhart, D., 2015. Sustainable practices for landfill design and operation. Springer, New York, USA.
[xviii] Sapsford, D., Cleall, P., Harbottle, M., 2017. In Situ Resource Recovery from Waste Repositories: Exploring the Potential for Mobilization and Capture of Metals from Anthropogenic Ores. Journal of Sustainable Metallurgy 3, 375-392.