Coal’s decline continues as figures show homes and businesses got more power from the sun for an entire 24 hours last weekend

The sun provided British homes and businesses with more power than coal-fired power stations for 24 hours last weekend.

While solar power has previously beaten coal for electricity generation over a few hours in the UK, Saturday was the first time this happened for a full day.

Analysts said the symbolic milestone showed how dramatic coal’s decline had been due to carbon taxes, as solar had “exploded” across the UK in recent years.

National Grid data gathered by climate analysts Carbon Brief showed that 29 gigawatt hours (GWh) of power was generated on Saturday by solar, or 4% of national demand that day, versus 21GWh from coal-fired power stations.

“This first for solar reflects the major shifts going on in the electricity system,” said Carbon Brief in its analysis. “Last weekend’s solar breakthrough could not have happened without the increase in solar capacity. However, an ongoing collapse in coal generation was the more immediate cause.”

Solar power installations have surged in the UK over the past two years, driven by incentives and falling costs. The industry says there is now 12GW of electricity-generating capacity, out of the UK’s total capacity of 80-90GW.

Meanwhile, a series of major coal-power plants have closed, including the last coal plant in Scotland in March. Other coal units at Rugeley, Eggborough, Ferrybridge and Fiddlers Ferry, representing around 8GW of capacity, will close in coming months.

“The economics of coal are terrible at the moment,” said Peter Atherton, an influential energy analyst at Jefferies International bank.

“The economics of coal have deteriorated dramatically over the last 18 months. Coal-power plants are now heavily loss-making, and the reason is low wholesale prices... [and] what’s really hit coal is the increase in the carbon tax, the move from £8 to £18 under the carbon floor price floor last year, which really hurt them and flipped the economics over from barely profitable to loss-making.”

Going into last winter, the UK had around 18GW of coal capacity, Atherton said, but this year there will be less than 10GW.

However, he said solar had “exploded” in growth in the UK. “There’s no doubt solar has been on this incredibly rapid growth over the last few years.”

That growth is likely to flatten out in coming months due to government cuts to incentives. Subsidies for large solar farms end this month, and the number of householders putting solar on their roofs has already plummeted since the changes took effect in February.

The solar industry welcomed the news of the record last weekend. “Analysts expect solar will attract a third of all energy investments globally until 2040, so it is set to play a major role in tackling climate change and delivering clean power.

“It is also one of the cheapest major renewables and the most popular with the British public, so why the UK government has stepped back from supporting this winning technology is difficult to understand,” said a spokeswoman for the Solar Trade Association.

Carbon Brief said that coal’s woes meant it was providing a historically low level of power to the UK: “In 2016, coal has supplied less than 10% of UK electricity on 18 of 102 days, including every day in April so far. Coal has probably never supplied such a small share.”

The drop in coal use was the main cause of the UK’s greenhouse gas emissions falling 4% in 2015 and last year solar, along with other renewable energy, provided more electricity than coal for the first time over a whole quarter.

The energy secretary, Amber Rudd, said in a major policy announcement last year the UK would phase out coal power by 2025, but both Atherton and Carbon Brief said it was clear that result was already in train well before Rudd made her pledge.

“The problem the government has at the moment is keeping coal on, not phasing it out,” said Atherton.