Solar farms can boost biodiversity – but more data is needed

solar panels and wildlife

In the latest of his solar series for elemental, Dr Seb Berry discusses the latest report on solar farms’ impact on wildlife.

The latest report on ecological trends on solar farms in the UK provides another fascinating snapshot of the potential of solar farms to boost levels of biodiversity on well managed sites. Solar Habitat 2024 has been produced by Solar Energy UK, Lancaster University, and consultancies Clarkson & Woods and Wychwood Biodiversity, building on their first report published last year.

First the good news. The survey reveals that vulnerable species such as hares and red-listed skylarks are among the most commonly seen wildlife on UK solar farms. A total of 279 skylark individuals were seen across the 87 sites surveyed last year as part of the study. Among the other red-listed bird species seen were yellowhammer, linnet and starling.  The brown hare, a species of conservation concern, made up 40% of mammal observations. Other mammals included badger, fox, weasel and common shrew. Unsurprisingly, sites well managed for biodiversity also recorded a boost for invertebrates.

Report analyst Hollie Blades, PhD researcher at Lancaster Environment Centre, Lancaster University, said “Our understanding of biodiversity at solar farms is growing as more ecological monitoring data are collected across an increasing number of UK solar farms. Groups such as birds and invertebrates appear to respond positively to biodiversity-focused management at solar farms and we hope to continue working with the data to further unpick the patterns identified.”

These are all welcome findings, but in themselves they tell us little of course about what’s going on across the bulk of the more than 1,400 solar farm sites across the UK. We’ve known for at least ten years that solar farms can be built and operated to high biodiversity standards. As long ago as 2013, the first UK Solar PV Strategy acknowledged that there was “increasing evidence that solar farms can provide benefits to biodiversity”. This message therefore is nothing new. 11 years on, the real question is how many UK solar farms actually fall into that category and what can be done to improve those that don’t?

Monitoring biodiversity

This year’s survey covers 87 sites (just 6% of the more than 1,400 solar farms in the UK), from companies which have adopted Solar Energy UK’s “standardised approach to monitoring biodiversity on solar farms.”  This standardised approach includes five  “site management” categories ranging from 1 “Optimal management for biodiversity” down to 5 “site unmanaged.”  Surprisingly perhaps, given the nature of the sample selection used for the study, just 43% of the sites were placed in the highest categories 1 and 2. 45% were placed in category 3 “site cut or grazed throughout the season, blanket spraying of herbicides beneath panels”, while a further 11% of the sample were placed in the bottom categories 4 and 5.

It’s impossible to know how representative these results are of the wider industry, something that future Solar Habitat reports will need to address, as more developers and more sites participate in monitoring. It’s also unclear to what extent the findings of this latest biodiversity report can be applied to the potential cumulative impacts of mammoth solar farm developments such as the proposed 840MW, 5 square mile Botley West development in West Oxfordshire. The average size of solar farm monitored in the Solar Habitat report was just 10MW, ranging from 1MW to 70MW, in line with the typical size of solar farms in the UK. As Oxfordshire County Council pointed out in their response last month to Photovolt Development Partners, the developers of the 840MW Botley West scheme, “A development of such exceptional scale and impact requires exceptional mitigation that goes beyond the planting of hedgerows and woodland belts to soften views…” Few surely would argue with that.

The report helpfully points out that “it is not known if sites included in the Solar Habitat sample are representative of how sites are managed across the UK”, while the SEUK media release adds that “we are hopeful that the methodology will be used by more ecological consultancies and be applied across more solar farms. Gathering data from more sites means that we can ascribe greater confidence to our findings”. This is rather key to understanding what’s really going on at the many hundreds of established solar farms not covered by this report. As a former Vice-Chair of the STA, I’ve been trying for some time to get to the bottom of how many of the UK’s 1400 solar farms can actually be said to be operating to high biodiversity standards. No-one knows.

For the latest on solar innovation, visit InstallerSHOW 2024 – running 25-27 June at the NEC.