Solar produced more electricity than coal in the United Kingdom in May, for the first time ever.

During the month coal generation fell to zero on some days, according to UK-based energy tracker Carbon Brief.

The UK has already announced it would phase out all coal-fired power plants by 2025. The electricity sector makes up nearly a third of the country’s greenhouse gas emissions.

The government plans to transition much of its generation to natural gas and has recently cut subsidies to solar and made it more difficult to develop onshore wind power generation.

In the United States renewable energy sources are making up a larger part of output.

Hydro, wind, solar, biomass, and geothermal sources made up nearly a fifth of all the electricity generated in the US in March, according to the Energy Information Administration. Renewables surpassed coal in Texas.