The UK solar industry has reached its latest milestone after generating more energy in a full month than coal for the first time, according to analysis by Carbon Brief.

This follows the first of several signifiers of solar’s growth against fossil fuels earlier this year when the renewable technology overtook coal generation for the first full day in April and for the first week from 3 May.

New analysis has now shown that solar generated an estimated 1,336GWh of electricity throughout last month, 50% more than the 893GWh output from coal.

Carbon Brief’s findings are based on those of Sheffield Solar, a research project working in collaboration with the National Grid to track solar generation in the UK. Embedded generation like solar is not centrally metered, making it difficult to track as a result.

While the figures remain estimates, the analysis claims solar generated 6% of the UK’s electricity needs throughout May versus less than 4% from coal. This marks a significant increase this year alone, with just 1% of solar compared to 17% for coal in January.

In light of the global shift away from fossil fuel generation, coal in particular, the findings are largely symbolic but do show the major and ongoing changes in the UK’s evolving energy mix.

A combination of low carbon output and increased irradiance as the UK moves into summer has been cited as the cause for the recent changes in generation, while closures of coal-fired plants are also on the rise.

Instead, the UK’s power is increasingly coming from renewables as well as slightly cleaner forms of generation like gas, with coal set to be phased out by 2025.

There have been calls for this to be implemented as early as 2023, while renewables have also been referenced as a replacement to the generation promised by Hinkley Point C, which has yet to be confirmed.

Speaking to Solar Power Portal, Mayer Brown partner Tom Eldridge said that the “significant milestone” revealed more about the anticipated decline of UK coal than it did the future of solar.

“Whilst solar deployment has moved ahead of other renewable technologies (due largely to the industry’s ability to reduce installation costs), the policy landscape and subsidy regime remains very challenging, particularly for developers and investors in both small and larger scale systems. 

“Opportunities in the solar sector are now more focused in the secondary market for “grandfathered” assets, and, going forward, in private wire projects, and investments linked to solar storage, batteries and vehicles,” he said.