The UK added 730MW of new solar capacity in 2021, an increase of 36% on 2020 when 538MW was installed, according to Solar Energy UK.
Total PV capacity in the UK is now 14.6GW, up 5.3% on 2020.
Some 369MW installed in 2021 was rooftop solar, the highest total since 2015, said Solar Energy UK.
It added that the new growth in the rooftop sector is fully subsidy-free.
Solar Energy UK said high natural gas prices have helped stimulate the rooftop market, with commercial energy buyers installing onsite solar to protect themselves against the volatility of buying electricity based on fossil fuels.
Solar Energy UK chief executive Chris Hewett said: “2021 was the year the UK’s solar industry came of age.
“We are now seeing stable, sustained growth across the sector, with order books overflowing.
“As fossil fuel energy bills soar, rooftop solar in particular is now very popular.
“More and more consumers and businesses are investing in solar because they know it is a proven way to cut their energy bills and carbon emissions. It is also now a cheap way to charge EVs and decarbonise heating.
“The UK solar industry is ready to meet the challenge of supplying this demand, and we call on the government to match the ambition of the market.
“Setting a deployment target of 40GW would support the industry to take long-term investment decisions and build the workforce skills that will create thousands of green jobs across the whole country.”