Britain has secured a record volume of solar power capacity through its latest renewable energy auction, the government announced on Tuesday, marking a major step toward its clean energy goals. The auction offered guaranteed electricity price contracts to renewable energy developers and resulted in 6.2 gigawatts of onshore wind, solar, and tidal projects winning support. Of this, solar dominated with around 4.9 GW, the highest ever secured in a single round.

The UK aims to largely decarbonise its electricity sector by 2030, a target that will require a rapid expansion of renewable sources such as wind and solar. Energy Secretary Ed Miliband said the move would help lower energy bills and shield households and businesses from volatile fossil fuel prices, while strengthening the country’s energy security.

Under the Contracts for Difference scheme, developers bid for government-backed price guarantees for the power they generate. If market electricity prices fall below the agreed “strike price”, the government pays the difference; if prices rise above it, producers return the excess.

This was the seventh CfD auction, and together with a record offshore wind round announced last month, a total of 14.7 GW of capacity has been secured, enough to power around 16 million homes.