Analysis: UK nuclear output falls to lowest level since 1982

The 50TWh of low-carbon electrical power from existing nuclear power plants (purple wedge, left) is set to disappear as they are all arranged to nearby 2035. This output might be replaced by the under-construction Hinkley C and proposed Sizewell C plants (lighter purples, 25TWh each).

Another contributor was 2 brand-new interconnector cable televisions– the North Sea Link with Norway and IFA2 with France– which assisted increase electricity imports, in spite of an extended interruption for the existing IFA1 cross-channel cable.

Fully decarbonised?

The 12% bump in coal generation (black) left the fuel well listed below its 2019 figure and still at historically low levels. There were 90 complete days without coal generation in 2021, Carbon Brief analysis programs, below 180 days in 2020, however still above 83 in 2019 and 21 in 2018.

Changing mix.

The figures in the article are from Carbon Brief analysis of information from BEIS Energy Trends chapter 5 and chapter 6, as well as from BM Reports. The figures from BM Reports are for electricity provided to the grid in Great Britain just and are gotten used to include Northern Ireland.

Low-carbon low.

Many recent headings have actually focused on Germanys deliberate technique to end its usage of nuclear power, with three of its staying 6 reactors having turned off at the start of the year.

The figure reveals that there is a shortfall in between existing strategies and what would be required to totally decarbonise the grid, even with relatively beneficial assumptions. Any shortfall is likely to be fulfilled by fossil fuels, breaching the governments 2035 aspiration.

Few, however, have noted the substantial declines in nations including France and the UK– albeit forced instead of due to policy options– as aging reactors come to the end of their lives.

The governments advisory Climate Change Committee (CCC) states the UK ought to “move away” from massive biomass power plants, once existing subsidy contracts expire in 2027.

In Carbon Briefs analysis, the BM Reports numbers are also changed to represent electrical power utilized by power plants on site and for generation by plants not linked to the high-voltage national grid. This includes lots of onshore windfarms, in addition to commercial gas integrated heat and power plants and those burning land fill sewage, gas or waste gas.

There had been steady and rapid progress towards this goal over the previous years, with eight years of successive falls in carbon strength from 486gCO2/kWh in 2012 to simply 183gCO2/kWh in 2020.

The government aims to have a completely decarbonised power system by 2035– however the most recent figures show it is going in the wrong instructions. The figures are based upon Carbon Brief analysis of data from BM Reports and the Department of Business, Energy and Industrial Strategy (BEIS).

Assuming all of the above and provided demand in 2035, as expected by the federal government, there would still be a shortage of approximately 20TWh to fully decarbonise the grid (red).

Plunging nuclear.

The UK federal government has set an ambition to “completely decarbonise” the electrical power system by 2035 as part of its method to reach net-zero greenhouse gas emissions by 2050.

Regardless of the record fall in 2021, low-carbon sources still created over half of UK electricity (51%), as the chart above shows, with fossil fuels comprising 39% and imports another 8%.

Electrical power generation from nuclear reactor in the UK, terawatt hours (TWh), 1920-2021. Source: BEIS and Carbon Brief analysis. Chart by Joe Goodman for Carbon Brief using Highcharts.

On the other hand, if utility company EDF wins approval to extend the life of the 1.2 GW Sizewell B nuclear plant beyond 2035, as it wants to do, then this would assist close the shortfall in low-carbon output.

This is since electricity generation from nonrenewable fuel sources was some 9% higher than a year earlier, of which almost 90% came from greater gas output. Coals share remained listed below 2%, in spite of growing somewhat compared to a year previously, while gas increased its share from 34% to 37%..

Especially, despite increasing in 2015, gas generation stayed some 8% listed below 2019 levels and well below previous highs, at nearly a 3rd lower than output from the fuel in 2010.

This challenge is illustrated in the illustrative figure below, which shows the existing makeup of UK electrical power generation on the left and, in round numbers, the circumstance in 2035 on the right.

They show that the carbon intensity of electrical power generation rose last year by nearly 10% to 199 grams of carbon dioxide (CO2) per kilowatt hour (gCO2/kWh), up from a record-low 183gCO2/kWh in 2020.

Two brand-new reactors at Hinkley Point C in Somerset are because of come online later the government and this decade wishes to protect a deal for a similar plant at Sizewell C throughout this parliament.

Together, these new nuclear plants would roughly replace existing nuclear output.

Electrical power generation from the UKs nuclear reactor fell by another 9% in 2021 to just 46TWh, less than half the peak in 1998 and the most affordable in nearly four decades.

The UKs nuclear output has actually plunged to its lowest level because 1982, Carbon Short analysis shows.

The remaining 3% of the mix in 2021 was from pumped hydro storage (1%) and other sources (2%), including the UKs growing fleet of battery storage websites, in addition to waste incinerators.

In combination with the decrease in nuclear output, this implies the UKs low-carbon electrical energy generation saw its biggest ever 1 year fall of 17TWh, shown in the chart below.

Nevertheless — with demand barely recuperating from coronavirus lockdowns in 2020 — low-carbon sources still generated over half of UK electrical power in 2021, consisting of 19% from wind, 14% from nuclear, 12% from biomass and 4% from solar..

Existing contracts for difference (CfDs) imply an extra 9 gigawattts (GW) of offshore wind is because of come online in the next couple of years and will generate roughly 40TWh each year (mid yellow).

For illustrative functions, Carbon Brief has assumed that imports and other sources continue to supply around 30TWh of electricity each year by 2035.


BEIS historic electricity information, including years before 2009, is adapted to reflect on-site generation and integrated with information on imports from a different BEIS dataset.

Sharelines from this story.

The chart listed below shows a more granular photo of UK electricity generation given that 2010, with renewables broken down into its constituent parts.

Utilizing biomass to produce electrical energy is not zero-carbon and in some scenarios could lead to greater emissions than from fossil fuels. There are more valuable uses for the worlds limited supply of biomass feedstock, the CCC states, consisting of carbon sequestration and hard-to-abate sectors with couple of alternatives.

In order to totally decarbonise the grid by 2035, low-carbon sources will need to replace the approximately 40% of need that is presently fulfilled by nonrenewable fuel sources. At the very same time, need is expected to increase by around 15% by 2035 as a rising share of heat and transportation is electrified.

( The federal government is also supporting the advancement of small atomic power plants, the first of which it wants to see coming online in the “early 2030s”.).

Electrical energy generation from nuclear power plants in the UK, terawatt hours (TWh), 1920-2021. Middle: Share of UK electricity by source, %, 1920-2021. UK electricity generation by source, terawatt hours, 2010-2021. Biomass grew by 2% to account for 12% of UK electrical energy in 2021, almost a 3rd of the overall from all renewables. The UK electricity mix in 2021 (left) and 2035 (right) broken down by source, in round numbers of terawatt hours.

The 9% drop in 2021, due to retirements and failures at the UKs aging reactors, contributed to a record 17 terawatt hour (TWh) fall in low-carbon electricity in 2015, with wind generation also falling 15%.

Combined generation from coal and gas in 2015, at 127TWh, was some 55% listed below 2010 levels. Imports reached their highest level on record, at 25TWh and 8% of the mix in general.

The prime minister Boris Johnson has set a target of 40GW of offshore wind by 2030, indicating an extra 12-14GW on top of those currently contracted or expected to win CfDs in the next auction. Reaching this target would mean roughly another 60TWh of low-carbon generation (pale red).

Electrical power generation from the existing UK nuclear fleet is set to decrease even more as the reactors reach their scheduled retirement, with all except Sizewell B in Suffolk due to nearby 2030.

Last years boost in fossil fuels to compensate for the fall in low-carbon output implies the carbon strength of UK electrical power increased by 9% to 199gCO2/kWh, Carbon Brief quotes.

If a few of the UKs existing renewable capability were to close, if imports were to fall or if plans and targets for new nuclear and overseas wind were not met then there would be a larger shortfall to completely decarbonising the grid in 2035, with the danger that any gap would be filled by nonrenewable fuel sources.

Biomass grew by 2% to represent 12% of UK electricity in 2021, almost a 3rd of the overall from all renewables. Some two-thirds of the biomass output is from “plant biomass”, primarily wood pellets burnt at Lynemouth in Northumberland and the Drax plant in Yorkshire. The remainder was from a range of smaller sites based upon land fill gas, sewage gas or anaerobic digestion.

The UK electrical power mix in 2021 (left) and 2035 (right) broken down by source, in round numbers of terawatt hours. Source: Carbon Brief analysis. Chart by Joe Goodman for Carbon Brief utilizing Highcharts.

It shows that increased generation from gas (dark blue, up 9%) and imports (red, up 37%) compensated for reduced low-carbon products in 2021.

Fossil fuels, mainly gas, supplied around 40% of the UKs electrical power in 2015 — some 130TWh (dark grey). To satisfy the federal government ambition, this would all require changing.

Much of the UKs existing sustainable capability– with an expected output of 130TWh in an average year, however closer to 120TWh in 2021 — will still be operating by 2035 (light yellow).

The Times, Observer and Daily Express reported preliminary arise from this very same analysis.

Minimized sunshine hours and below-average rainfall triggered 9% and 26% drops in solar and hydro generation, respectively, with the reported capacity of both sources hardly changing.

UK electrical power generation by source, terawatt hours, 2010-2021. Source: BEIS and Carbon Brief analysis. Chart by Joe Goodman for Carbon Brief utilizing Highcharts.

The next CfD auction, which is currently open and will announce results this summer, is because of protect another 12GW of capacity, consisting of up to 5GW of onshore renewables and 6-8GW of overseas wind. This would suffice to generate roughly 50TWh (dark yellow).

In part, this was due to the truth that demand hardly increased from the lockdown-induced lows seen in 2020 (bottom panel).

A big percentage of biomass subsidies are due to expire in 2027 and the oldest wind and solar farms will begin to reach completion of their life, but, for illustrative functions, Carbon Brief has actually presumed that all existing renewable capability will stay operational.

This implies bringing the carbon intensity of the grid — the amount of CO2 produced per system of electrical energy generation — down, or a minimum of extremely close to no.

The analysis of carbon intensity is based upon the method released by National Grid ESO.

The chart likewise shows the stark reduction in wind generation in 2021 (light blue) as above-average wind conditions in 2020 paved the way to the most affordable average wind speeds in a decade.

This is displayed in the figure below, which charts the expansion and subsequent decline of the UKs nuclear output.

Leading: Electricity generation from low-carbon sources and nonrenewable fuel sources, TWh. Middle: Share of UK electrical power by source, %, 1920-2021. Bottom: Generation by source, TWh, 1920-2021. Source: BEIS and Carbon Brief analysis. Chart by Joe Goodman for Carbon Brief using Highcharts.

The UKs windfarms likewise had a tough year in 2021, with generation falling by an estimated 15%– despite increasing capacity — as a result of the most affordable average windspeeds in a decade.