For the first time since 1882, when the first coal-fired power plant started running in the UK, the country has gone coal-free for a full week, according to the National Grid's Electricity System Operator (ESO).
And Britain is now on course to generate electricity with zero carbon by 2025, the operator said.
The milestone was reached as the country's Environment Agency issued a stark warning about coastal communities under rising threat of floods due to climate change.
The coal generator was off between around 1.30pm on May 1, 2019 and the same time on May 8, according to ESO.
"While this is the first time this has happened, I predict it will become the 'new normal,'" Fintan Slye, Director of ESO said in a statement. "As more and more renewables come onto our energy system, coal-free runs like this are going to be a regular occurrence. We believe that by 2025 we will be able to fully operate Great Britain's electricity system with zero carbon."
The landmark target of a week without coal was achieved thanks to a long-term strategy aimed at increasing the use of renewable energies, from offshore wind to domestic scale solar panels, Emma Pinchbeck, deputy CEO at RenewableUK, told CNN.
"Wind has become a mainstream power source for the UK, providing up to 35% of our electricity over the weekend. Renewables have been crucial to phasing out dirty coal," she said.
"The coal phase out is just the beginning of a move away from fossil fuels to low carbon living, to avoid the enormous risks of climate disruption. Last week, the Committee on Climate Change said we can only achieve net-zero emissions with a massive increase in renewables."
Regulation and profitability have played a role: under European Emissions Performance standards, old plants would have had to fit expensive new kit by the end of this year, and the economic conditions for coal are poor, Pinchbeck said. Carbon pricing has also had an impact.
Then, there's the Climate Change Act. which mandated country a near zero carbon power sector by 2032, and which drove major investment in low carbon technologies such as renewables from 2008, she added. The UK government has also committed to phase out all coal plants by 2025.
ESO data from the coal-free week shows that renewables (wind, solar, hydro, and biomass) accounted for around 23% of the total power, with natural gas and nuclear providing 46% and 21%.
That means coal has been displaced by renewables, not gas, Pinchbeck said, explaining that there was more current and planned investment in the former.
Threat to coastal communities
The news came as the Environment Agency's chairwoman Emma Howard Boyd warned that entire coastal communities might need help to move "out of harm's way in the longer term," as global temperatures rise by an expected 4 degrees Celsius (7.2 degrees Fahrenheit) by 2100.
"We can't win a war against water by building away climate change with infinitely high flood defenses," Boyd said in a statement, adding that £1 billion ($1.3 billion) a year needed to be invested in flood management to combat the emergency.
On May 2, the country's Committee on Climate Change (CCC) urged the government to cut its greenhouse gas emissions to net zero by 2050. Currently the UK has a target of curbing greenhouse gas emissions by 80% by 2050, compared to 1990 levels. Emissions fell by 42% in 2016.
The CCC said the new target is "necessary, feasible and cost-effective." But it will require drastic action, including phasing out petrol and diesel vehicles completely by 2035, planting 30,000 hectares of trees each year and cutting beef, lamb and dairy consumption by 20% by 2050.