The UK has generated zero power from coal-fired plants for the second time this week.
National Grid told ELN there was no coal on the system between midnight and 5am this morning.
The generation used instead was a mixture of gas, nuclear and wind.
It comes after National Grid also confirmed no coal plants were running between midnight and 4am on Tuesday “for the first time since our records began”.
A spokesperson said: “Some generators may decide to turn off at certain times as it is not economical for them to run. Summer is also a time when plants are often out for maintenance which might have contributed to this.
“As System Operator, it is our role to operate the system in the most cost effective way. We are generation neutral and cannot be seen to favour one type of generation over another, therefore this wasn’t planned by us and is merely a coincidence. This is likely to have been down to a mixture of outages and clean dark spreads.”
According to experts, it was the first time solar farms generated more power than coal “over a full week”.
Last year the UK Government announced plans to close all coal plants by 2025.
Environmentalists took to the streets of London over the weekend to protest against the use of fossil fuels and David Cameron’s “backward” policies on tackling climate change.