The government’s initial findings for 2014 show that nuclear output fell to 94.87TWh last year, the lowest level of generation since 2009 when output fell to 94.26TWh.
In 2012 and 2013 nuclear output was recorded at highs of 133TWh and 123.5TWh respectively.
But a flurry of unplanned outages across EDF Energy’s nuclear fleet last summer caused output levels to slump, taking a toll on EDF Energy’s earnings for last year.
EDF’s UK Ebitda for 2014 fell by 8.5 per cent year on year to euro €1,941 million, due mainly to unplanned outages at its nuclear stations in Heysham and Hartlepool.
The nuclear operator lost 2.5GW of nuclear capacity over the summer after a crack was found in a boiler at Heysham-1. As a safety precaution all units of the same design were removed from service for safety inspections.
All the units have now returned to service but only at 75-80 per cent capacity, knocking 240MW off EDF Energy’s fleet.
The shortfall was met by increased use of gas-fired power which rose to its highest share of the energy mix since 2011 at 31 per cent. Gas-fired power found favour in the market across 2014 as historic lows on the UK’s wholesale gas market caused a switch away from coal-fired power.
Coal was still the dominant fuel within the energy mix but in 2014 made up only 34 per cent of the total, its lowest share since 2011 when coal burn provided 32 per cent of all electricity.
Meanwhile, wind generation increased its share of the UK’s total generation by just 1 percentage point, rising from 8 to 9 per cent of the energy mix.
The government will follow Thursday’s provisional 2014 data with a final report on 26 March.