Prime Minister Keir Starmer's pledge is seen as crucial to Britain meeting its legal obligation of reaching net zero greenhouse gas emissions by 2050 to combat climate change.

- What has Labour promised? -

Labour promised at the election in July to deliver "zero carbon electricity by 2030".

It means the production of electricity, previously dominated by coal and currently reliant on natural gas, would not contribute to overall CO2 emissions.

Wind, solar, nuclear, and tidal power would instead generate the vast majority of electricity used in Britain from the beginning of the next decade.

Labour says its plans will reduce reliance on fossil fuels from overseas that fluctuate in price, such as Russian gas, and lead to cheaper household energy bills.

- How does it plan to achieve clean power? -

Labour has said it will work with the private sector to double onshore wind, quadruple offshore wind, and triple solar power by 2030.

This involves a "phased and responsible transition" towards renewables for the North Sea oil and gas industry.

Labour promises to invest in carbon capture and storage, hydrogen and marine energy, and says new nuclear power stations will "play an important role".

It also plans to "maintain a strategic reserve of gas power stations to guarantee security of supply".

- What early steps has Labour taken? -

One of Labour's first moves was to scrap the Conservatives' de-facto ban on new onshore wind farms. It also revised planning policy to make it harder for local councils to oppose energy developments.

Labour has launched a publicly owned green energy company called Great British Energy to spur investment in renewable projects. The company is set to receive pound8.3 billion ($10.8 billion) of taxpayers' money over the next five years.

Last month, Starmer announced planned government investments of nearly pound22 billion over 25 years to support three carbon capture projects that will remove 8.5 million tonnes of CO2 emissions each year.

In early October, Britain's last coal-fired power station closed, making the UK the first G7 country to end its reliance on the fossil fuel for electricity.

- How are opponents and experts reacting? -

Critics say the plan risks blackouts and rising bills. Environmentalists have welcomed Labour's ambition, though many experts question whether it is achievable.

Tuesday's report by the publicly owned National Energy Systems Operator (Neso), which runs the UK's electricity grid, sought to lay out how the decarbonisation can be achieved.

It said pound40 billion of annual investment will be needed to 2030 and that some nuclear power stations which are due to close in 2028 will need to stay open longer.

More than twice the quantity of transmission network infrastructure -- pylons, cables, substations etc. -- that was built in the last decade will need to be built in the next five years, according to Neso.

That equates to more than 1,000 kilometres (620 miles) of power lines, which will likely face stiff opposition.

Neso added that the government must also quicken the connections queue so that completed green energy projects no longer wait years to connect to the grid.

If "the scale of those challenges is matched with the bold, sustained actions that are outlined in this report, the benefits delivered could be even greater," said Neso chief executive Fintan Slye.

- What is the government saying? -

Energy Secretary Ed Miliband said the analysis was "conclusive proof that clean power by 2030 is not only achievable but also desirable".

It "can lead to cheaper, more secure electricity for households, it breaks the stranglehold of the dictators and the petrostates, and it will deliver good jobs and economic growth across this country in the industries of the future," he wrote in the Guardian newspaper.