How can we make solar energy work for the environment as much as for the climate?

Drawing from his team’s latest Perspective piece, Fabio Carvalho provides an overview of the growth of the solar energy industry in the UK and how we can better evaluate its impact on the environment.

Solar farms are fast becoming a common sight across Britain. It is not hard to spot one by the side of a road or by going up a hill and looking down at what once was arable land, especially if you are in southern England.

The recent push to decarbonise energy systems to meet climate change targets has meant renewable energy technologies have grown substantially in the UK in the last decade, and none more so than solar energy.

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Solar farms are fast becoming a common landscape feature in Britain, and they provide a great opportunity to create wildflower meadows to benefit pollinators and other invertebrates if managed accordingly © Fabio Carvalho

Utility-scale solar energy generation in the form of ground-mounted solar farms will likely play a crucial role in delivering the amount of clean energy needed to help the UK meet its Net-Zero target by 2050. However, solar farms represent a novel land use which brings with them a whole set of new challenges that we are only now beginning to explore.

Sustained long-term growth

The UK solar energy sector grew from less than 100 MW installed capacity in 2010 to more than 13,200 MW in 2019, a remarkable growth in the space of less than 10 years that is set to continue into the 2020s.

Solar farms alone are likely to account for more than 15,000 MW installed capacity by the end of 2023, potentially doubling to more than 30,000 MW by the end of 2025, being projected to reach 70,000 MW by the mid-2030s.

Considering the price of solar panels has dropped by more than 80% in the past decade, I would not be surprised if this growth trajectory was revised upwards before the end of the year.

What does this mean for the environment?

These numbers are clearly good news for climate change mitigation efforts. It is indeed reassuring to know the days of burning fossil fuels to generate electricity are (hopefully) numbered, at least in this part of the world.

However, the growth of solar energy (and renewable energies in general) has implications for the environment just as much as for climate change mitigation, though to date we have only scratched the surface into trying to understand the environmental impacts of utility-scale solar farms.

Renewable energy technologies generally have lower energy densities (0.5-20 W m-2) than fossil fuels (100-1000 W m-2), and thus demand considerably more land to generate similar amounts of energy. In fact, solar farms are estimated to take between 1.6 to 2.4 ha of land for every megawatt installed capacity. This brings both risks and opportunities for the wider landscape.

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Solar farms in Britain are typically managed as grasslands, but they can incorporate a number of additional ecological features (e.g. tree lines, hedgerows) to help reconnect long-fragmented habitats © Fabio Carvalho

Solar farms in the UK are usually built on former agricultural land and managed as grasslands. A common land management goal within them, at least in the UK, is the creation of diverse and structured wildflower meadows to benefit wildlife and generate environmental and biodiversity net gains.

Despite their substantial land take, solar farms offer significant scope to achieve such goals since they normally have a relatively small infrastructure footprint, with less than 2% of land commonly disturbed during operations.

Considering their long operational lifespans (typically 25-40 years) and the fact that they are largely undisturbed by people, there is considerable potential for solar farms to restore degraded farmland habitats, if managed accordingly, to help reconnect long-fragmented landscapes that have been mostly broken by intensive arable cultivation.

The research challenge ahead

There is very little evidence to date on the effects of solar farms on hosting ecosystems.

Research effort in this field is scattered around different regions of the world under different climates and environmental conditions. An added complication is the myriad of ways in which solar farms are managed, and not all operators adopt sustainable land practices.

One of the main challenges therefore is generating standardised and replicable data to offer a broader picture of the environmental impacts of utility-scale solar energy under different settings.

Collecting data from such places is difficult though given access restrictions and (as I throw my hands up in despair!) a lack of long-term funding to survey an ever-increasing number of sites around the country.

How can we deliver environmental benefits from the energy transition?

This is a question that has kept my colleagues and I at Lancaster University occupied for the last few years, and one that is likely to keep us busy for the next few.

Given there are only so many researchers for so many solar farms, we thought it would be a good idea to pass the baton to solar farm operators and field ecologists to do the heavy lifting for us (not quite, but the thought of letting others get drenched in the fields of Britain is comforting!).

We partnered up with professional ecologists from Clarkson & Woods Ecological Consultants and Wychwood Biodiversity, as well as industry insiders from Solar Energy UK, to come up with a standard list of methods to facilitate environmental data gathering from solar farms.

The protocol, recently published in Ecological Solutions and Evidence,  is designed to be implementable by industry and field practitioners, while offering enough flexibility in terms of the depth and nature of the data collected.

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Lead author of the Perspective article Fabio Carvalho at a solar farm in England in summer 2021 © Fabio Carvalho

We hope this will be a catalyst to kick-start large-scale data collection from solar farms up and down the country (and beyond) to provide much-needed evidence to feed into land use policy and industry practice. Our ultimate aim is to inform sustainable land management practices within the solar energy sector to deliver environmental benefits beyond those of climate change mitigation.

If solar energy is here to stay, as it seems likely, we need to continuously think of ways to embed environmental gains into the land use planning process to ensure we do not miss the boat on biodiversity when tackling the climate crisis. Our standardised protocol is hopefully a significant step forward in the right direction.

Read the full Perspective: “Towards a standardized protocol to assess natural capital and ecosystem services in solar parks” in Issue 4:1 of Ecological Solutions and Evidence.

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