Coal generation is “edging closer to extinction” during the summer season after supplying just 1.3 per cent of Great Britain’s electricity in the three months to the end of June.

There were 812 “zero-coal” hours over the quarter, according to the latest Electric Insights report from Imperial College London, as many as during the whole of 2016 and 2017 combined.

Britain saw its longest ever coal-free run during the period, covering more than three days (76 hours) between 21 and 24 April, as well as several stints lasting more than two days. The previous record was nearly 41 hours in 2017.

The report, commissioned by Drax, also found coal’s share of generation fell below 1 per cent for the first time ever during June.

“At the times when coal is running, it is now at a bare minimum,” it added.  “Apart from two cold spells in April, coal rarely went above 1 GW – just half the peak output of one of Britain’s remaining coal-fired power stations.

“Overall, the fleet ran at just 3 per cent of its rated capacity across the quarter. One question is why is this small amount still needed – could Britain simply run with no coal over the whole summer?”

Coal’s monthly share of generation

Source: Electric Insights, Imperial College London and Drax

The report warned that, having picked the low-hanging fruit, an “era of slow progress” on decarbonisation in the power sector “may already be upon us”.

The carbon intensity of the power grid averaged 196gCO2/kWh over the quarter – a new low for Great Britain. However, this figure was down just 2 per cent when compared to the same quarter in 2017.

“The reason is that generation during the summer months has settled on a similar pattern: 25 per cent nuclear, 25 per cent renewables, 40 per cent gas, 8 per cent imports and 2 per cent coal,” the report explained.

“Until these shares start shifting, the recent experience of 200gCO2/kWh in summer and 275gCO2/kWh in winter will not budge.”

The recent heatwave brought a record-breaking summer for solar output which hit a new high of 9.39GW on 27 June. This helped to offset an accompanying “wind drought” that lowered production by 60 per cent between January and June. At one point, wind output dropped to just 273MW – the lowest level in two years.