Wind energy: a green paradox

Wind power is 100% renewable, and one of the greenest energy sources available. As such, it’s a key player in the race towards net zero - but beneath its squeaky clean credentials and virtually non-existent operational emissions, wind energy has a murky green secret, write Sophie Leese and Alexandra Evans.

While it’s certainly true that operationally, wind energy generation is as green as it gets, in a bid to maximise low-emission energy, the industry has steamed ahead, overlooking the environmental impact of wind turbine dismantling and decommissioning. 

On the face of it, the figures look good. Around 80-90% of a floating offshore wind turbine can be made from concrete and steel, both of which – despite the high carbon footprint of their manufacture – can be readily recycled through well-established methods. But – and this is a very big but – the turbine blades, made from composite materials that are designed specifically to be lightweight, thin and aerodynamic, are extremely challenging to recycle. The vast majority of decommissioned blades end up in landfill. 

A wake-up call for wind

The wind industry is at a turning point. We are heading into the first big wave of turbine decommissioning as the original turbines from the 1990s and early 2000s are reaching end of life. Faced with the sudden need to dispose of tens of thousands of turbine blades, and a lack of established recycling processes, how we manage the waste associated with decommissioning on such a scale will make or break the future of wind as a green energy source.

It is estimated that there are over 11,000 operational wind turbines in the UK today, and around 341,000 in the world. But with the UK government aiming to produce 50GW from offshore by 2030 (up from 13.9GW currently), huge countries like the USA and China accelerating their capacity fast, and the industry only just taking off across the vast expanses of Africa, the untapped potential is immense. As a planet, we’re only at the start of our wind-powered journey. 

Restrictive recycling 

In the context of a weight-based recycling system, the relatively low weight of blades compared to the rest of a turbine structure has, to some extent, given us permission to neglect their impact. Blades may not weigh much, but at around 50m in length (and set to get bigger), and with research from the University of Cambridge predicting 43 million tonnes of blade waste worldwide by 2050, landfilling the non-biodegradable blades is not only a significant waste of raw materials; it will use up a phenomenal and ever-increasing amount of space.

Turbine manufacturers are beginning to catch on. There’s increasing commitment across the sector globally to reuse, recycle or recover 100% of decommissioned blades by 2025/30, with several countries already imposing a ban on the landfilling of turbine blades. 

For some time, the industry has been working hard, in the shadow of net zero innovation, to find a realistic solution to this potentially catastrophic challenge. Technologies have sprung up to recycle the composites involved, grinding them down to use in bricks, for example, or using heat or chemicals to separate glass fibre from resin. But all of these methods significantly degrade the physical properties of the resulting materials. While they can be used to make things such as sports equipment and insulation, ultimately, processes that expend energy and yield a lower-quality product are simply uneconomical. 

A full-circle future 

What we’re really striving for is a circular economy – looping 100% of the blade material back to make new blades. In 2023, a Danish manufacturer announced it had developed a new chemical process that does exactly that. It can extract the raw materials from the composites used in existing turbine blades while retaining the original strength and physical properties needed to create new ones, again and again. 

This is a significant and exciting development, offering hope for a sustainable, circular process that has the potential to secure wind power’s position, genuinely, as one of the greenest renewable energy sources going forward. But, amid a rush of lab-based innovation across the sector, this particular solution – like many others – has yet to be tested at scale, and its commercial viability is currently unknown.

End of life planning 

With precious little time until this crisis spins out of control, the development, testing and expansion of solutions like the one above will need to be fast-tracked in order to handle the impending volume of waste. That means we need government funding for research and development to take technologies out of the lab and into the world, cross-industry collaboration to come up with the best possible solutions, fast, and real incentives for blade recycling, with a move away from weight-based waste targets.

The race to net zero has exposed a single-mindedness, where ‘green’ design is limited to operational emissions, and the consequences of that are only beginning to surface. We are playing catch up now, hoping to limit the exhaustive environmental impact of our energy production, from manufacture right through to end of life. Emerging design must incorporate the bigger environmental picture, and consider the full lifecycle of turbines and their materials, to ensure carbon wins during operational life don’t get cancelled by inefficiency or environmentally unsound waste management at end of life.

Sources for reference:

University of Cambridge, School of Technology

Wind Europe

Engineering & Technology

Department for Business & Trade