The latest figures from the Department of Energy Security and Net Zero (DESNZ) show that solar capacity has risen by 8.1% year on year.
As of the end of May 2025, the UK has a total of 18.9GW of solar capacity across 1,803,000 installations, with 1.4GW of solar capacity added since May 2024. Last month saw 23,098 new solar installations with a combined capacity of 89MW completed across the UK, a figure which DESNZ notes is the second-most new installations in a month, behind March 2025. The department also emphasises that this is higher than the average figures seen between 2016 and 2021.
While most of the UK’s solar PV installations by volume are domestic, making up 1,552,266 of the nation’s total solar installations, these installations only make up a total of 30% of the total MW capacity of UK solar. In May of this year, 66% of new solar PV was installed on residential buildings, adding 65MW of capacity, up from last month’s total of 59MW.
Across 2024, a total of 191,000 solar installations came online in the UK, a 3% decrease from 2023’s figure of 197,000. However, this number is far greater than the average number of annual installations between 2016 and 2022, which stands at 63,000 annually.
A recent report from Solar Media Market Research estimates that the UK is expected to add between 3GW and 3.5GW of new solar capacity in 2025. Approximately 20% of the 2.3GW of solar deployed across 2024 came from residential rooftop installations, with commercial rooftop installations contributing another 20%.
However, other recent analysis indicates a number of factors that could hinder the growth of solar capacity in the UK this year – of these, the increasing time taken for planning applications to be approved is arguably most significantly, with Solar Media Market Research analyst Josh Cornes noting that the average waiting time for planning approval for a solar project has risen to 45 weeks in recent years. Shortening the timeframe for solar PV power plants to gain planning approval has become an increasing focus of the UK government in recent months, with the Industrial Strategy announced last week pushing for the recruitment of 300 new planning officers to address significant under-resourcing in planning departments across the UK.
