England has consolidated its position as the primary driver of solar PV deployment in the United Kingdom, accounting for over 70% of the total installed capacity. As of April 2025, the country has reached 17,781 MW, mainly through small-scale systems, while Scotland, Wales, and Northern Ireland remain far behind, some showing no growth compared to previous quarters.

According to data published by the Department for Energy Security and Net Zero, systems up to 4 kW already exceed 4,136 MW in installed capacity and continue to dominate the residential segment. Additionally, systems between 4 and 10 kW and between 10 and 50 kW now total 1,231 MW and 1,412 MW, respectively, reflecting growing adoption among high-consumption households and small businesses.

The category of solar parks larger than 25 MW — critical for achieving net-zero targets — accounts for just 2,523 MW, and its expansion has been moderate in the first four months of 2025, with few new projects added. In contrast, plants between 5 and 25 MW now total 4,699 MW, driven largely by rural developments in southern England.

In absolute terms, England leads the solar PV deployment, followed distantly by Scotland, which contributes approximately 17%. Wales and Northern Ireland together account for less than 10% of the national capacity.

Falling costs and residential adoption

The deployment trend is underpinned by a steady decline in the levelised cost of electricity (LCOE). According to cost data released for the 2024/25 fiscal year, the average annual cost for a domestic PV system has dropped to £1,392 per kW, a 26% decrease compared to five years ago. This decline is a key driver of adoption, with households accounting for over 86% of all registered PV installations.

Moreover, solar systems integrated into new homes are even more competitive. The Department notes that for new builds, the cost has fallen to £931 per kW, while retrofits average £1,256 per kW.

A grid increasingly powered by renewables

Solar deployment in 2024 contributed to a record year for renewable electricity generation, which reached 144.7 TWh, making up 50.8% of the UK’s power mix, the highest on record. Within this figure, solar generation reached 14.8 TWh, up 6.5% from 2023, despite lower average solar radiation conditions.

“Solar generation increased despite a drop in annual sunlight hours,” the official report states. This growth is attributed to the expansion of installed capacity, especially in the residential segment, which added over 147,000 new systems during 2024, many of them outside subsidy schemes and unregistered with MCS.

Regional disparities and future challenges

The regional disparity is stark. While England continues to add new capacity every month, Scotland has barely reached 1,200 MW in domestic systems as of April 2025, contributing minimally to national growth in recent quarters.

“Although projects like Moray West and Neart na Gaoithe add more than 1.3 GW in offshore capacity, their impact will only be reflected in future updates,” the official document recognises.

Meanwhile, Wales is experiencing a slowdown in project approvals, attributed to local regulatory hurdles and the lack of specific incentives for self-consumption. Northern Ireland, for its part, has shown no significant growth in the first quarter of 2025.

Forecasts and energy dependency

Despite the rise in renewables, the UK increased its energy dependency on imports in 2024, moving from 40.8% to 43%, according to the “Energy Trends” report from March 2025. This is largely due to falling domestic production of gas and oil, further emphasising the strategic importance of clean energy sources such as solar.

The Government aims for at least 70% of electricity to come from low-carbon sources by 2035, making solar deployment in underdeveloped regions critical to the country’s climate goals.

With falling costs and strong momentum in the South, solar energy is emerging as a cornerstone of the UK’s climate strategy. But to meet the 2050 net-zero targets, it will be essential to ensure regional equity in solar deployment and address the structural barriers slowing progress in Scotland, Wales, and Northern Ireland.