Hagshaw Hill, about 30 miles south of Glasgow, is the site of Scotland’s first commercial wind farm – opened in 1995. In July this year, after almost three decades of operation, ScottishPower Renewables announced that it is finally being decommissioned.

This is happening ahead of repowering work next year, when 14 new turbines will be installed, which will take it from being a 16 MW site to a capacity of over 79 MW.

The example of Hagshaw Hill teaches us two important lessons about renewable energy in the UK.

First, that we need to focus on investing into the electricity grid, because unlike Hagshaw Hill, most sites with older turbines can’t simply quintuple installed capacity. If we don’t solve the grid capacity issue it will be a major constraint on reaching national net zero goals. We may also need to keep existing turbines working longer than intended, until upgraded grid capacity enables us to replace them with larger, more powerful models.

Moreover, with planning issues still holding back the renewables sector in the UK, it is important to make the most of the turbines that we already have.

The second lesson is that wind farms, looked at in the right way, can keep doing their job well beyond the limits of their expected design life. The turbines installed at Hagshaw Hill were able to generate more than 895 MWh of electricity before being replaced, which greatly exceeded the expectations of what would have been possible when they were first erected.

Exceeding expectations
Typically, manufacturers still talk about wind turbines being designed for a lifespan of around 20 years. But we now know from experience that with good operational practices and effective maintenance, many can keep working efficiently beyond the 30-year mark. This is something that we are getting better at all the time, which means that blades keep turning and the profits keep earning for well over a decade beyond what was intended when an initial investment decision was made.

As an onshore wind O&M business that has been around for over two decades, we have seen impressive steps forward in industry best practice. This is making it cheaper and more environmentally sustainable to keep turbines in tip top condition.

There are a number of factors that are helping to improve industry practices, but a large part of the improvement comes down to learning by doing. As the industry matures, there are more experienced wind technicians and a better market of suppliers.

Five years ago, scrapping any component that went wrong and replacing it with a new one was commonplace. It was often the default option whatever the issue. Today, with the supply chain cost pressures exacerbated by the war in Ukraine and a focus on the circular economy, we are seeing far more repair and reuse.

What’s more, you can’t rely on manufacturers still providing spare parts for turbines as they age beyond their planned lifespan. But there are now a number of specialist businesses that can re-engineer and repair everything from slip rings and printed circuit boards, through to generators.

...wind farms, looked at in the right way, can keep doing their job well beyond the limits of their expected design life.
 

Decreasing costs
There are also modern technologies to bring down costs and enhance performance, enabling the sort of preventative maintenance that would not have been possible even a few years ago. For example, affordable drones can be used to deliver detailed inspection of blades, which takes around an hour per turbine and is far quicker than previous methods. Artificial intelligence can also be used to analyse the images captured by the drones, to automatically look for signs of fatigue and turbine protection failure and flag these to a technician.

Finally, there are economies of scale. We know that it is typically cheaper to deliver service contracts for turbines in Scotland than England, because there are more turbines and it is a more developed industry.

While you can’t account for all the potential issues that can go wrong with a turbine – stray golf balls are still an occupational hazard where I’m from in Scotland – as a sector we are getting a lot better at shifting to prevention rather than cure, which minimises downtime and keeps capacity online. This is good news, as it looks like we will hopefully see a massive increase in investment and expansion of wind energy in the UK the other side of the next general election, whatever the result.

Finally, a word of concern. We have already lost 150 wind turbines since the start of this decade. Without lifetime extension, by 2040 we could lose over half of our currently installed wind capacity. But knowing what is possible in maintaining ageing turbines as valuable assets, it remains critical that the wind services market keeps evolving to help deliver the energy transition at the lowest possible cost.

The views and opinions expressed in this article are strictly those of the author only and are not necessarily given or endorsed by or on behalf of the Energy Institute.