Unseasonal weather triggered a surge in wind power generation in the third quarter of this year.
That was a stand-out highlight in the latest GB Electricity Market Summary by energy data analyst EnAppSys.
The report said a very stormy August resulted in a spike in wind generation, which accounted for a record 22% of Britain's fuel mix on the 17th day of this month.
Across the quarter, wind provided 7% of the GB power mix while gas was the biggest contributor with 36%. Meanwhile, 22% came from coal-fired power stations, 20% from nuclear units and other sources, including interconnector flows into the country, provided the remaining 15%.
Paul Verrill, Director of EnAppSys, said: "Wind had little impact on the overall system for much of the quarter but a very stormy August did see levels of wind generation notably above the usual levels. This resulted in a very high share of overall generation come from wind farms at times, reaching record levels across the 17th August at 22% of total generation.
"The second quarter had been notable for lower than usual levels of coal-fired generation and higher than usual levels of gas-fired generation, as gas prices fell due to an oversupply of gas and high levels of gas in storage.
"This trend meant that the third quarter began with a high share of electricity generation from gas-fired CCGT (Combined Cycle Gas Turbine) plants and more modest levels of generation from coal-fired plants, with the low gas prices also contributing to lower than usual power prices.
"As the quarter progressed, gas prices increased due to rising demand fuelled by colder weather and fears that Russia could stop gas flowing into Europe through Ukraine. This made gas plants less competitive and boosted coal's share of the fuel mix in September.
"By the end of the quarter, the gas and coal-fired fleets were producing similar levels of generation."
The strong performance of gas was attributable to rapidly declining gas prices caused by excess gas supplies in storage, as well as the temporary closure of reactors at Heysham 1 and Hartlepool nuclear stations following the discovery of unexpected cracks in one of the boilers at Heysham.
It was also triggered by lower than expected levels of coal-fired generation due to some plants remaining offline during the summer while maintenance work was carried out. This led to a fall in coal's share of the overall power mix, from 26% in the second quarter to 22%. However, towards the end of the quarter coal generation picked up again as some units came back online and colder weather triggered a rise in gas prices, which made gas plants less competitive.
To look at the full report, please visit the following page on the EnAppSys website: http://www.enappsys.com/news_and_rep/Q3%202014%20Market%20Summary.pdf.