The UK’s greenhouse gas emissions plunged by 8.4 percent last year, as household energy consumption slumped, the use of coal for electricity generation fell, and policies on climate change took effect, according to recently released government statistics.

Carbon dioxide output fell by almost a tenth, as renewable energy generation rose to a new record high, accounting for nearly a fifth of electricity.

It was the biggest fall in emissions since 1990. Over the last five years, following a sharp fall in 2009, emissions appeared to have reached a plateau, with slight rises in some years owing to increasing coal use. The price of coal has dropped on world markets, as shale gas has sapped demand in the U.S., leaving a glut.

Green campaigners welcomed the fall, but they warned that more must be done to reach targets.

In part, the slump in carbon output was down to record average high temperatures across the UK in 2014, which drove down demand for heating and led to a big drop in household energy consumption – even though bills rose over the year.

The emissions fall was a boost to Ed Davey, secretary of state for energy and climate change, ahead of a difficult general election for the Lib Dems. The party has traditionally relied on its green credentials with voters, but this has been a harder sell when in coalition.

Davey said: “2014 was truly record-breaking year for low carbon generation. Our plan to decarbonize the economy while it grows is working – we’ve reduced our emissions by 8 percent, increased the amount of electricity we’re getting from renewables and seen the economy grow at the same time. It is crucial we continue to build a low carbon energy sector based on home grown sources, as it is crucial to improving our energy security, as well as stimulating economic growth and reducing emissions.”