The impacts and implications of solar farms for bats and invertebrates in England

Abstract

1. A global energy transition towards sustainable renewable sources is being driven by global
agreements. Simultaneously there is a call for increased biodiversity protection. Solar
energy is the source of renewable energy with the highest and fastest growth, both
globally and in England, and rapid development is set to continue. This creates a greengreen dilemma, where the expansion of renewables could lead to the demise of
biodiversity if not carefully assessed, managed and monitored. At present there are
knowledge gaps with regard to how biodiversity is affected by solar farm developments.
2. This project set out to understand the placement of solar sites in England, and the
implications that solar farms may have on bats and aerial invertebrates in an agricultural
setting. This work was completed through a map-based desk study and through fieldwork
at paired control and solar sites in the south west of England.
3. Key thesis findings were that solar sites are generally being placed sensitively within the
ecological landscape when compared with a random point dataset. It is also identified that
solar sites have a significantly negative effect on bats, with six of the eight species/species
groups recorded showing a significant decrease in activity at both the centre of solar farms
and at the boundary features which boarder them. Further work suggested that the
mechanism for this decrease was not caused by a difference in prey availability, as solar
farm sites generally had similar levels of insect abundance compared with matched control
sites. However, the abundance of some invertebrates was found to differ significantly at
solar farms compared to control sites.
4. Recommendations: These findings highlight the importance of the thorough assessment
(desk based and field survey) that is required to assess the biodiversity impacts of solar
farms both academically and commercially. This should be aligned with the Environmental
Impact Assessment process as appropriate, and applying the mitigation hierarchy is
important. There needs to be a nationally coordinated approach to avoid siting solar farms
in areas which are ecologically sensitive, and adaptive planning must be applied to ensure
that new research findings and developing best practice is implemented. The design of
solar farms should reduce impact through the inclusion of innovative technology to make
ii
panels more efficient, with the aim of reducing the area required for development, and
restore biodiversity at both the operational and decommissioning phase of a project.
Compensation and offsetting approaches should be applied to solar farm sites to manage
the direct loss of associated habitat, and particularly to manage the indirect effects on
volant species groups. Monitoring of biodiversity mitigation should be a priority to
continue filling the knowledge gap in this area.
5. Outlook: To progress the findings of this project, further research should focus on
monitoring the spread of solar developments in England and undertaking further
biodiversity focused research, particularly in the agricultural setting. The impact of solar
panels on the ecological function of boundary features requiresfurther attention, with the
aim to advise mitigation for biodiversity. The mechanism causing bats to be negatively
impacted by solar farms needs to be understood by studying behaviour, and whilst
differences in invertebrate abundance is unlikely to be a causal factor, a focus on how this
trophic group (particularly aquatic invertebrates) are interacting with solar panels requires
further attention.
6. The findings of this study should be used to support a cohesive and collaborative approach
across governments, policy makers, investors and designers when managing the greengreen dilemma so that renewable energy can be expanded without a cost to biodiversity

Date of Award	10 Dec 2024
Original language	English
Awarding Institution	University of Bristol
Supervisor	Gareth Jones (Supervisor)