Scientists at Lancaster University have studied satellite images of the UK to produce the most accurate assessment yet on how much land solar farms occupy.
The study, in collaboration with NextEnergy Capital and published in the journal Progress in Energy, show that the amount of land occupied by solar farms is between 15,580 and 17,364 hectares - this is around 0.06% to 0.07% of the total UK land area.
This calculation is slightly lower than previous estimates that had total UK solar farm land use at 0.08%. These figures all relate to ground-mounted solar farms and do not include panels on houses or other buildings.
In their study, which will help resolve uncertainties around solar farm land use, the researchers manually digitised 1,088 UK solar farms in the most comprehensive study of its kind. This involved tracing the boundaries of solar farms, and the blocks of solar panels within the sites, from satellite images up to January 2024 using GIS, specialist mapping software.
The findings are an improvement on previous estimates, which were extrapolated from the generating capacity of, and land occupied by, a sample of solar farms.
A total of 15,580 hectares of solar farms appeared on satellite images. The additional range of the researchers' estimate takes into account remaining solar farms that are registered on the Government's Renewable Energy Planning Database but do not appear within recent satellite imagery, because available satellite images covering the UK differ in age.
The researchers say that having an accurate estimate for the amount of land used for solar farms is essential for future planning decisions.
Dr Hollie Blaydes, Senior Research Associate at Lancaster University and lead author of the study, said: "We believe this is the first solar farm dataset that has been generated using manual digitisation methods from satellite imagery.
"Photovoltaic energy is projected to play a pivotal role in meeting the UK's decarbonisation targets. Having an accurate figure of UK solar farm land use is essential for properly informing future strategic planning decisions around energy and food security, boosting biodiversity and fulfilling our Net Zero commitments."
The researchers say that around 95%, of land used by solar farms was formerly agricultural land - with around two thirds of this formerly arable land and around a third improved grassland. However, the authors highlight how it is very difficult to accurately determine the quality of agricultural land on which solar farms have been built as, they say, current agricultural land quality maps are not accurate enough for planning decisions and the map for England needs updating.
Other solar farms are built on land types including former collieries, quarries, and landfill sites.
The researchers also estimated how much land would be required to meet the UK's future renewable energy goals.
The researchers say that if we continue to deploy solar in the same proportions - the proportion on rooftop in relation to solar farms on the ground - as we have been doing, then a total of between 0.22% to 0.39% of total UK land (or 0.45% to 0.82% of agricultural land) might be needed for solar farms in the future to meet our energy and decarbonisation objectives. This figure includes existing solar farms.
However, if we deployed all future solar installations to meet our most ambitious solar targets using only ground-mounted installations, rather than a mixture of ground-mount, rooftop and floating, then that could take up 0.72% of total UK land (or 1.5% of agricultural land).
The researchers say several factors could influence the size of new solar farms in the future. "Increased efficiencies of solar technologies mean fewer panels are needed to generate the same amount of electricity, which could see reductions in the size of solar farms," said Professor Alona Armstrong, co-author of the study from Lancaster University.
"On the other hand, land within solar farms that does not have solar panels mounted on it, such as margins and corridors, if managed suitably, can deliver significant other benefits, including providing habitat for wildlife such as pollinating insects or birds. Delivering these benefits could also affect future solar farm sizes.
"Land use for solar in the UK is set to continue to grow given our Net Zero target. Ensuring that they also deliver benefits to nature as well as continue to support food production will help mitigate growing land use pressure. As we move towards meeting Net Zero, there will be trade-offs on how we best use our land," she said.
The study received funding support from the UK Government through Defra's Nature for Climate Fund R&D Programme (Defra NCF ETPP-33/C10) and the UKRI Engineering and Physical Sciences Research Council Impact Acceleration Account (EP/X525583/1).
NextEnergy Capital provided boundary data for solar farms in the UK and contributed industry insight.
The study's findings are detailed in the paper 'Shedding light on land use change for solar farms'.
The paper's authors are: Dr Hollie Blaydes, Professor Duncan Whyatt, Dr Fabio Carvalho, Dr Juliana Silveira and Professor Alona Armstrong from Lancaster University; and Hing Kin Lee and Kevin McCann from NextEnergy Capital.
DOI: 10.1088/2516-1083/adc9f5
