UK PV market booms, best start in a decade

Josh Cornes, market research analyst at Solar Media, tracked UK solar installations in the first half of 2025 and found that the growth in installed capacity over the past six months was almost the same as for the whole of 2024.

In 2025, the UK's solar installed capacity has exceeded 2GWp, ushering in the best start in nearly a decade, and there are 3.GWp of large-scale ground-mounted photovoltaic projects under construction.

At the beginning of the year, it was expected that the UK market would add 3GWp to 3.5GWp of installed capacity in 2025. With the completion of the Cleve Hill project and the installation of household rooftop solar exceeding expectations, the UK's solar installed capacity has quickly exceeded 2GWp.

The installed capacity of ground-mounted photovoltaic projects still accounts for more than 70%, and the installed capacity has exceeded 1.5GWp. This is mainly due to the completion of Clive Hill (373MW), the UK's first National Major Infrastructure Project (NSIP). In addition, 14 projects with an installed capacity of 50MWp or more have been completed, accounting for more than 60% of the total installed capacity, including projects recently connected to the grid by Low Carbon and NextEnergy with a total installed capacity of more than 400MWp.

As can be seen from Figure 1, large-scale solar projects (>50MWp) dominate the market, accounting for nearly 70% of the installed capacity built in 2025, and this trend has strengthened year by year since 2018.

Another 1GW of projects have been under construction for more than a year, and the standard construction period is 30 to 60 weeks, so the installed capacity of ground-mounted PV projects is expected to more than double that of 2024.

Commercial rooftop solar installations remained stable as expected, with a good start and an increase of about 20% year-on-year.

The government supports the development of residential rooftop solar through major incentives such as mandatory installation of solar on new houses, and the continued support policy has a huge impact on the overall rooftop solar system market. The government also announced that it will allocate another £10 million.

Large-scale ground-mounted solar project filings increase

This year has seen record filings for large-scale ground-mounted solar. So far this year, filings have exceeded 7GWp, with more than 5GWp filed in the second quarter, the best first half of the year ever and the highest filing quarter ever.

As expected, this growth has been driven by government projects, with more than 3GW of projects filed with the relevant departments in the past three months. Since the Labour government came to power, 12 projects (with a total installed capacity of 6.6GWp) have been submitted to the Planning Inspectorate.

However, it is difficult to tell whether the increase in the number of solar national infrastructure projects entering the planning system since the election is due to Miliband's rapid approval of development consent orders (DCOs) and the support signals from the government, which has boosted the confidence of developers, or because the Clean Power 2030 plan has prompted them to act sooner.

Filings at the local planning authority (LPA) level have also been strong, with more than 3GWp filed in the first half of the year, but this will further increase approval waiting times.

Despite record-high filings and developers submitting second-stage grid connection applications, most projects have reached the planning stage. Therefore, the next three months are expected to be relatively quiet, giving local planning authorities an opportunity to deal with the 8GWp of projects that have not yet been approved.

Project rejections are also worth paying attention to, with 14 projects (total installed capacity of more than 750MW) rejected in 2025. Nearly 90 projects (total installed capacity of nearly 2.6GW) have been approved at the local planning authority level, but more than 20% of the installed capacity of projects that have been decided this year has been rejected.

Projects have also been rejected at the appeal stage. Although all 14 projects rejected by the local planning authority at the beginning of the year were approved at the appeal stage, three of the six projects that have been appealed recently have been rejected, with Wood Lodge Solar Farm in Northamptonshire being the latest project to be rejected. There are currently 24 projects (1.3GW) under appeal, and another 20 projects (1GW) may appeal. Hopefully this trend will not continue.

The UK's operational solar capacity has exceeded 22GWp, of which nearly 14GW comes from ground-mounted photovoltaic projects. In 2025, planning applications at the local planning bureau and government level hit record highs. The support of the Labour government is leading the solar industry in the right direction, but there are still obstacles to overcome on the road ahead, such as slow planning approvals, prominent grid problems, and insufficient resources required to build such a large project.