The green sector generated more than £43 billion and employed nearly a quarter of a million people in 2015, official figures suggest.
Businesses working in the fields of renewable energy and low carbon technology and products had a turnover of £43.1 billion - worth 1.3% of total UK non-financial turnover, the Office for National Statistics said.
The equivalent of 234,000 full-time employees were working directly in the sector, which covers everything from wind farms to low emission vehicles and charging points, the data show.
Renewable energy, ranging from offshore wind to domestic solar panels, generated £14.9 billion, while energy efficiency products and services such as installing insulation and designing sustainable buildings generated £13.9 billion.
More than half of the UK's turnover from onshore wind activities was generated in Scotland - with a turnover of £1.5 billion, the figures show.
Together, direct and indirect economic activity associated with the renewable and low carbon sectors, generated an estimated £77.7 billion and employed the equivalent of 432,000 full-time staff.
Rebecca Williams, energy specialist at environmental charity WWF, said the figures showed the low carbon industry was a "boon" to the UK economy.
"It is pumping billions into our economy, growing jobs and boosting innovation, and that is before we take into account the beneficial impacts it is having on our environment.
"With over 25% of our electricity being produced from renewable sources, the low carbon sector has now truly come of age, but to meet our climate obligations we must go further.
"As we prepare to leave the EU it is now more important than ever that we embrace the low carbon sector, and at least maintain our current environmental regulations."
She urged the Government to provide investors and employees with clarity over future action by publishing its "long overdue" plan to reduce greenhouse gas emissions.
A Business, Energy and Industrial Strategy Department spokesman said: "The UK Government's support for renewable energy has helped attract over £56 billion of investment since 2012.
"Through our ambitious industrial strategy and the new £290 million support scheme opened this week, we're committed to building on our strengths and taking advantage of the jobs and growth the low carbon economy provides."
Industry body RenewableUK's deputy chief executive, Maf Smith, said: "These figures demonstrate that one of the biggest British success stories of recent years is the rapid rise of the renewable energy sector, which is currently growing faster than the rest of the economy.
"C lean energy is now a mainstream source of power and a real force to be reckoned with.
"It is providing far-reaching economic benefits to the UK, from Liverpool to Lowestoft and from the Isle of Wight to the Isle of Mull.
"Renewable energy needs to be at the heart of the Government's new industrial strategy."