Photovoltaic installations surge! UK solar power generation reaches new high

Ember's latest report shows that solar power generation reached a record 9.91TWh in the first half of 2025.

A new report from clean energy think tank Ember shows that 2025 was the strongest year on record for solar power generation in the UK. Solar power generation increased 32% year-on-year in the first six months of the year, reaching a record 9.91TWh.

Since the beginning of 2025, solar power generation has continued to break records, with peak generation reaching new highs for five consecutive months starting in March. On July 8th, the UK grid set a record for instantaneous solar power generation, with 14GW of solar power supplied simultaneously throughout the country, a 44% increase over the annual peak of the previous five years.

This surge in power generation is primarily attributed to two factors: record-breaking sunshine hours this summer and a significant increase in installed photovoltaic capacity. Josh Cornes, market research analyst at Solar Media, noted that in the first half of 2025, the UK installed over 2GW of new photovoltaic capacity—nearly the total installed in 2024, marking the strongest start to a decade. The UK's total operational photovoltaic capacity now exceeds a peak of 22GW.

Residential photovoltaic installations are also on the rise. Ember data shows that residential PV installations have reached their highest level in a decade. Data released this month by MCS, a low-carbon technology certification organization, confirms that 120,000 certified panels were installed across the UK in the first half of 2025, a 37% year-on-year increase, breaking the previous record set in the first half of 2012.

Ember attributes this increased adoption of residential PV to two key drivers: a 10% year-on-year increase in energy prices (£152) and falling installation costs. MCS data shows that the average cost per kilowatt for residential PV has continued to decline since the summer of 2023, falling from £2,009/kW in 2023 to £1,590/kW this year.

The think tank also notes that since the 2019 expiration of the feed-in-tariff (FIT) system, which offered higher rates for systems under 4kW, the average size of residential PV installations has increased significantly. Over the past decade, the share of 4-10kW systems has climbed tenfold, from 5% in 2015 to 50% this year.

Wind and solar complement each other's strengths.

The think tank also emphasized that the UK's renewable energy mix, combining wind and solar power, effectively balances the country's fluctuating energy demand caused by its volatile climate. While the number of days with high sunshine increased significantly in the first half of 2025, wind power generation declined—a reversal of the situation in early 2024.

Ember calculations show that only 2% of days have recently experienced both low sunshine and low wind power, contributing to a record low share of natural gas generation in the grid in June of this year of 21%.

Ember analyst Frankie Mayo called 2025 a "golden year" for solar, adding: "The UK is benefiting from the recent surge in new PV installations, which has reduced reliance on expensive natural gas during periods of below-average wind speeds. This underscores why the UK needs the synergy between solar and wind power to ensure a strong, stable, and clean year-round electricity system."