Great Britain generated a record 8.0TWh of solar power during the second quarter of 2026, while renewable sources supplied 53% of total electricity generation, according to Montel’s Q2 GB Electricity Market Summary.

Wind remained the country’s largest source of electricity, generating 18.9TWh during the quarter, up 7% compared with the same period in 2025. It accounted for around 55% of all renewable generation, Montel said.

The report also highlighted that instantaneous solar generation reached a new national record of 15.42GW on 23 April. At the same time, more than 2.4TWh of potential wind generation, equivalent to approximately 15%, was curtailed during the quarter.

“The generation mix continued to shift towards lower-carbon sources, with renewable generation accounting for more than half of total output,” said Phil Hewitt, director at Montel.

“Renewable generation totalled 34.2TWh during Q2 2026, accounting for 53% of total GB electricity generation, the highest share of any fuel group,” he added.

According to the report, fossil fuels contributed 23% of Great Britain’s electricity generation during the quarter, while nuclear accounted for 13%, meaning that around two-thirds of the country’s electricity came from zero-carbon sources.

Montel noted that the growing share of renewable generation is increasing the need for greater flexibility across the electricity system.

“June’s record-breaking heatwave highlighted the changing dynamics of Britain’s electricity system,” Hewitt said.

He explained that strong solar generation pushed electricity prices lower during the middle of the day, while a combination of lower wind output, declining solar generation in the evening, rising demand and reduced combined-cycle gas turbine (CCGT) output due to high temperatures tightened system margins during peak evening hours. As a result, the system relied more heavily on battery storage, flexible gas generation and electricity imports.