Focus on research: Dr Paul Leahy, MaREI

Identifying sustainable applications for end-of-life wind turbine blades
Dr Paul Leahy

24 February 2022

Dr Paul Leahy is lecturer in Wind Energy at University College Cork and a funded investigator in the Science Foundation Ireland (SFI) MaREI Research Centre for Energy, Climate and Marine. He is also a principal investigator on several research projects including Re-Wind, a transdisciplinary circular economy project aiming to generate sustainable repurposed products from decommissioned composite material wind turbine blades. In this interview, he talks about the beginnings of his career, the merits of collaborative research and the future of energy in Ireland. 

Can you tell us about your academic career to date?

While I was studying Electrical Engineering in UCC I became interested in new energy technologies. I applied for a funded PhD position at the Culham Centre for Fusion Energy in the UK, supervised by Prof Patrick Carolan in Culham and Dr Sean Prunty of UCC. I worked on Doppler spectroscopy for fusion plasma diagnostics on a magnetic confinement experiment called COMPASS-D. Culham was the centre of fusion research in Europe and there were many talented scientists and engineers there. It was a great scientific training; the work challenged me, and I learned a huge amount there. I worked in industry for a few years, then took up a postdoc with Prof Ger Kiely in Environmental Engineering back in UCC. I’ve been a lecturer in Wind Energy in UCC since 2009, which has allowed me to combine my interests in energy and the environment. 

The SFI MaREI Centre has given Irish energy and environment researchers much greater scale and has raised the profile of our research in these areas. We always had high-quality researchers in Ireland, but in the past they often lacked facilities, scale, or international reach.




Many wind turbine blades in Ireland are reaching the end of their lifespan. More than 11,000 tons of blades are predicted to be decommissioned by 2025. Re-Wind is developing new reuse and recycling methods for the non-biodegradable composite materials used in wind turbine blades. What are some of the sustainable alternatives the team has discovered?

Early in Re-Wind we carried out a group brainstorming exercise to come up with as many ideas as possible. We identified around 50 different potential applications, but we knew we would have to focus on only a small number if we were to successfully develop them. The BladeBridge greenway cycle bridge in Midleton, Co. Cork and the BladePole electricity distribution pole in Georgia, USA, are our two flagship products. However, Re-Wind and other groups have identified many more potential applications for repurposed end-of-life blades such as boardwalks, structural elements for roofs, acoustic noise barriers for motorways, bicycle shelters, and glamping pods. Wind turbine blades are highly engineered for strength and durability. These valuable properties would be lost if the blades were downcycled into fillers or aggregates, so we believe that there are many repurposing applications that provide more sustainable uses for the blades. 

The early 2000s wave of wind farms constructed in Ireland will soon be nearing end-of-life, so there will be a continued flow of blades available for repurposing. One of our Re-Wind PhD students is now looking at ways to develop a business around end-of-life blade repurposing to ensure that these blades don’t end up in a landfill.

A US-Ireland-Northern Ireland initiative, the Re-Wind network is made up of experts from various disciplines and research institutes. How important is the collaborative aspect of the project?

It is absolutely critical. Many collaborative research projects are, in reality, separate parallel research strands that only briefly come together for annual meetings and writing reports, but Re-Wind was different from the outset. Blade repurposing is challenging as it requires many different areas of expertise and we didn’t have access to all of those in one department, institution, or even in one country. We have architects, structural engineers, wind energy experts, sociologists, geographers, sustainability and cleaner production experts across our partners in UCC, Georgia Tech, Queen’s University Belfast and Munster Technological University.                                                 

You’re also working on H-Wind, a MaREI Centre industry-led collaborative research project on the production of green hydrogen from offshore wind farms. How does this project work?

The H-Wind concept is to develop detailed technical designs for infrastructure to convert offshore wind energy to hydrogen, hydrogen storage facilities, and identify pathways to end markets. H-Wind is supported by SFI and key players in the offshore wind and hydrogen sectors: ESB, the Irish renewable energy project developer DP Energy, Norwegian floating offshore wind developer Equinor, and the infrastructure operator Gas Networks Ireland. We developed the H-Wind work programme to focus on the detailed research needs to locate, design and scale future hybrid offshore wind-hydrogen facilities.

From working in wind energy, energy storage and environmental sustainability research what impact, if any, has growing public interest in these fields had on your work?

In the past, renewables were often thought of as completely socially and environmentally benign, but the reality is more complex. Re-Wind has tried to take a broad view on the environmental, social, and economic sustainability of the wind energy lifecycle. We have learned a lot from taking a transdisciplinary perspective and from engaging with communities and industry. I think the public is now generally well-informed about the pros and cons of various energy sources. There is a healthy debate around the use of fossil fuels, the building of wind and solar farms, and the possible use of nuclear power.

Looking towards the future, what would your ideal energy system model for Ireland look like?

In a few years, wind energy will become the dominant source of electricity in Ireland. Technologies such as hydrogen, heat pumps, fuel cells and electric vehicles will allow wind energy to cross over into the important heat and transportation energy sectors, and these technologies will also help to address some of the issues with the variability of renewable electricity. The medium-term challenge is to reduce the use of fossil fuels as the complement to renewable generation. In the long run I would love to see the commercial development of nuclear fusion power, which would provide a flexible, scalable, almost zero-waste, zero-carbon energy system.

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