Britain could see its first full day without generating any electricity from coal on Friday, National Grid has said.
If the grid goes the whole of Friday without coal power then it would be the first continuous 24-hour coal-free period for Britain since use of the fossil fuel began.
National Grid's electricity control room tweeted: "It looks likely that today will be the first ever working day in Britain without coal since the industrial revolution!"
The electricity grid has been coal-free a number of times since last spring, as gas and renewables such as wind and solar play an increasing role in providing the country with power.
The longest continuous period until now was 19 hours - first achieved on a weekend last May, and matched on Thursday.
Coal has seen significant declines in recent years, accounting for just 9% of electricity generation in 2016, down from around 23 per cent the year before, as coal plants closed or switched to burning biomass such as wood pellets.
The Government has pledged to phase out coal - the most polluting fossil fuel - from the system by 2025 as part of efforts to cut carbon emissions in the UK.
Hannah Martin, from Greenpeace UK, said: "The first day without coal in Britain since the Industrial Revolution marks a watershed in the energy transition.
"A decade ago, a day without coal would have been unimaginable, and in 10 years' time our energy system will have radically transformed again.
"It is a clear message to any new government that they should prioritise making the UK a world leader in clean, green technology.
"They will need to get on with the coal phase-out plan and recognise the economic potential of renewable energy and energy efficiency.
"We can meet the UK's needs for skilled jobs and fair bills, whilst also meeting our climate targets."
If Britain goes without coal for the whole day, it is thought it will be the first time it has been without electricity from coal since the world's first centralised public coal-fired generator opened at Holborn Viaduct in London in 1882.