Efforts to decarbonise energy generation have slowed raising concerns that the UK's world beating progress on tackling climate change could stall.
While output from renewables reached new highs in 2018 there was a dramatic decline in the amount of new wind and solar projects coming online, according to the latest Electric Insights report.
The carbon intensity of electricity averaged 217 g/kWh last year. That was 8% lower than in 2017 but amounts to the slowest rate of decarbonisation since 2013. The fastest rate of power system decarbonisation happened in 2016 when carbon intensity dropped 85 g/kWh compared to 2018's decrease of 20 g/kWh.
Great Britain's carbon intensity must continue to fall by 6% a year over the coming decade to meet the Committee on Climate Change's target of 100 g/kWh by 2030.
But it's already projected to fall by slightly less than that - 5% - in the coming years due to the slump in new renewables and nuclear. Progress could be further dented if coal makes a comeback ahead of it coming off the system in 2025.
Commenting on the analysis Dr Iain Staffell of Imperial College London said:
"The UK has led the world in decarbonising electricity and that continued in 2018 as output from renewables hit new highs. The sharp fall in new solar and wind projects coming online is worrying, and the likelihood that this trend will continue raises serious questions over future progress towards meeting our climate targets."
In the last 12 months, fewer wind and solar projects were built than at any time since 2010. The Government's own forecasts expect this slump to continue into the next decade.
