Bringing Britain's energy system back under public ownership is the best way of going green, Labour leader Jeremy Corbyn has insisted.
He told a party conference on alternative models of ownership on Saturday that Labour needs to take a radical approach to battling climate change.
Mr Corbyn said: "The greenest energy is usually the most local. But people have been queuing up for years to connect renewable energy to the national grid.
"With the national grid in public hands, we can put tackling climate change at the heart of our energy system. To go green, we need and must take control of our energy."
The Labour leader told the London gathering that the UK should follow a global tide of public ownership.
"We can put Britain at the forefront of the wave of change across the world in favour of public, democratic ownership and control of our services and utilities.
"From India to Canada, countries across the world are waking up to the fact that privatisation has failed, and taking back control of their public services."
Mr Corbyn pointed to the collapse of Carillion as proof "corporate feather bedding" did not serve the country as he pledged Labour would bring energy, rail and water under public ownership.
"This is not a return to the 20th century model of nationalisation, but to catapult us into 21st century public ownership and public involvement."
The Labour leader promised a safety net for workers who lose out under energy transition similar to the one given by the US government to unemployed veterans after the Second World War.
"The devastation wreaked when our coal mines were closed is a brutal reminder of what can happen when communities are silenced and disregarded in the process of change. Never again.
"Our energy system needs to change, but it cannot be workers who pay the price.
"So just as the US GI Bill gave education, housing and income support to every unemployed veteran returning from the Second World War, the next Labour government will guarantee that if anyone is displaced by energy transition they will be offered retraining, a new job on equivalent terms and conditions, covered by collective agreements, and fully supported in their housing and income needs through transition."
Mr Corbyn said that the impact of climate change requires action at least as radical as that taken by the 1945 Labour government to rebuild Britain's economy after the war.
"The challenge of climate change requires us to radically shift the way we organise our economy.
"In 1945, elected to govern a country ravaged by six years of war, the great Attlee Labour government knew that the only way to rebuild our economy was through a decisive turn to collective action.
"Necessary action to help avert climate catastrophe requires us to be at least as radical.
"A green energy system will look radically different to the one we have today.
"The past is a centralised system with a few large plants.
"The future is decentralised, flexible and diverse, with new sources of energy large and small, from tidal to solar."
Mr Corbyn accused the Government of failing to deal with environmental challenges.
"Nobody is fooled by Michael Gove's reinvention of himself as an eco-warrior.
"Behind the rhetoric lies a trail of environmental destruction.
"This is a Government that has licensed fracking, declared a moratorium on renewable levies, while massively subsidising fossil fuels, dithered over tidal, held back onshore wind, U-turned on making all new homes zero carbon and is failing to take the necessary measures to meet our legal commitments to reduce CO2 emissions."
Tory chairman Brandon Lewis said Labour could not say how much energy renationalisation would cost taxpayers.
"Labour's plan to put politicians in charge of your electricity would mean nowhere to go when things go wrong. This didn't work last time, it would mean worse services, and ordinary working people will end up paying the price.
"This Conservative Government is the greenest government ever. We focus on what works for the public, to deliver lower prices and a higher quality service."