Q3 2019: Power system records

by Dr Iain Staffell – Imperial College London 

Britain’s power system had another record-breaking quarter, with renewable energy hitting new highs, while fossil fuels, demand and carbon emissions all hit new lows. 

24 of the records we track were broken over the last three months.

Wind farms provided more than half of Britain’s electricity for the first time ever. For an hour on the 4th of September, wind provided 52.4% of electricity – up from the previous record of 49.7% set back in January. The total share of renewables also broke new ground, supplying more than two-thirds of the country’s electricity for the first time ever on the 17th of August.

This high share of renewables drove the carbon intensity of electricity below 50 g/kWh for the first time ever. On 17th of August it hit just 43 g/kWh in the mid-afternoon; and the day as a whole averaged just 76 g/kWh, nearly a quarter below the previous record set in June.

Electricity demand also fell to a new monthly low of 28.6 GW in August, likely prompted by the good weather – along with continuing energy efficiency improvements. As demand falls and renewable output grows, Britain’s net demand also hit new lows. Instantaneous demand net of wind and solar output fell to just 8.1 GW on the 19th of August, one-sixth lower than the previous record set in June. 

No records were broken by conventional fuels (nuclear, coal and gas). However, when put together, total output from fossil fuels fell to new lows. Conversely, the share of all low-carbon generation (renewables, nuclear and imported nuclear) edged ever-closer to 100%. On the 17th of August, the share hit a new peak of 89%.

The tables below look over the past decade (2009 to 2019) and report the record output and share of electricity generation, plus sustained averages over a day, a month and a calendar year.¹ Cells highlighted in blue are records that were broken in the second quarter of 2019. Each number links to the date it occurred on the Electric Insights website, allowing these records to be explored visually.

1: The annual records relate to calendar years, so cover the period of 2009 to 2018.

2: Note that Britain has no inter-seasonal electricity storage, so we only report on half-hourly and daily records. Elexon and National Grid only report the output of large pumped hydro storage plants. The operation of battery, flywheel and other storage sites is not publicly available.

Lead author: Dr Iain Staffell