Fossil fuel generation has more than halved over the last decade, hitting a new record low in 2020.
Just 102.7TWh was produced by coal and gas-fired plants combined last year, compared with 230.5TWh in 2011, according to analysis from EnAppSys.
As carbon intensive electricity generation has fallen away, the renewables sector has become a dominant player in the power mix. In 2020, renewables produced a record 41% (120.3TWh) of Great Britain’s overall electricity output. This is up from 2019, when wind, solar and other renewables contributed 35% of the country's electricity, with generation growing by 15MTh.
This growth was mainly driven by a 25% increase in wind generation, which expanded up to 74TWh. This was largely due to increased deployment of offshore wind, as the UK continues to target the technology. In particular, Q1 was a notable windy period, marked EnAppSys, with a number of storms – such as Storm Ciara in February which pushed wind power to 44.26% – leading to substantial generation.
Wind generation was more than double the second biggest renewable contributor biomass, which produced 28.5TWh. Solar generation did not fair as well, falling from 2019’s total generation of 12TWh to 10TWh in 2020. This was despite record levels of output in Q2, which saw solar hitting a new peak generation record of 9.68GW in April for example.
However, wind, solar and hydro still collectively almost caught up to gas generation in 2020, with 91.6TWh generated by renewables versus 95.7TWh by gas-fired plants. When biomass is added in renewables easily overtake gas generation, which contributed 32.9% of the energy mix, or 95.7TWh. The gas fleet’s generation fell by 16% from 2019.
Nuclear – the third biggest source of generation – saw little change from 2019 levels, generating 50TWh and contributing 17.1% overall.
Coal power continued to decline at a rapid rate, with 2020 seeing 67 days and 16 hours without the fossil fuel in the mix. This was the longest period Britain has been without coal since it was first used to generate continuous electricity by Thomas Edison in London in 1882. The continued decline of the technology allowed a historic first, with Britain celebrating its first coal free Christmas.
A number of coal plants left the market helping to drive this decline, with the three Aberthaw B coal units going offline at the end of 2019 and the three Fiddlers Ferry units going offline in March 2020. With Calon Energy going into administration, its four CCGT plants – Baglan Bay, Severn Power 10 and 20, plus Sutton Bridge – also left the market.
Paul Verrill, director of EnAppSys, said that the record renewable generation together with lower demand allowed for the lowest levels of conventional generation in recent history.
“For a notable portion of 2020, these conditions meant that coal and gas-fired plants often fell down the merit order. Nuclear production was also down, in part reflecting contractual arrangements to take Sizewell offline during the May to September period to provide greater headroom to support system security,” he continued.
“The combination of low demand and high renewable output saw occasional requirements for actions by National Grid to increase system inertia by bringing on conventional spinning generation on occasions, most notably during the May Bank Holiday weekends at the height of the first lockdown.”
Low demand was driven by the COVID-19 lockdowns, which had a profound impact on demand patterns. This was particularly noticeable in the first lockdown with reductions of 20% compared to previous years. This meant that a new record all-time low level of demand was hit in May, with just 13.8GW required.
Throughout the whole of 2020, demand was down 7% on 2019, the largest decrease seen in any year since 2011. Demand was 238.2TWh, with an average of 27.1GW per half hour settlement period.
“Market prices fell materially in response to the low demand conditions,” continued Verrill, with day ahead prices falling to an average of £35/MWh, an 18% drop on 2019.
“Last year was also notable for periods of negative prices with some very low prices occurring – notably £-70.49/MWh on May 22 and £-65.94/MWh on June 28, with prices remaining negative for hours at a time on a number of occasions during Q2. These occurred during periods of low demand, when large volumes of wind had to be bid down or switched off.”
EnAppSys’s analysis for 2020 follows National Grid ESO hailing the year as its greenest ever within its statistics for the year, pointing to record wind and solar generation, along with the remarkable coal-free period.