Addressing colleagues at the Labour Conference this afternoon, he accused the Government of “slashing funding for the renewables industry”.
He said a Labour government would make use of the UK’s “huge natural renewable resource” and “immense heritage of scientific and engineering experience”.
He told the conference: “We will ensure we will be world leaders in de-carbonising our economy.
“And we’ll do it partly through a publicly owned energy supply partly based on alternative energy sources.
“Where the Tories have dithered and delayed to deliver zero carbon initiatives, we will absolutely commit to building projects like the Swansea Tidal Lagoon.”
An independent review in to the green energy project concluded that it was cost effective and would make a “strong contribution” to the UK’s energy supply while bringing down carbon emissions.
But the Government has yet to sign off on it, despite the results of the study being available since January.
Critics say the delay is because the company behind the plans has not yet “put together a proposition to government that is sufficiently compelling”.
Speaking to the BBC in July, Richard Howard, head of energy for think tank Policy Exchange, said: “In the time in which this project has been developed we’ve seen massive, radical reductions in the cost of solar energy, offshore and onshore wind and that will continue.
“So actually locking yourself into a tidal lagoon for 90 years might not actually be the right option.”
Mr Howard has previously acknowledged that the the £1.3billion project would create jobs in and around the Swansea area.
But writing in January, he argued that amount of money would create jobs wherever it was spent.
He said: “The Government could instead choose to spend the same money on alternative sources of energy, or other forms of infrastructure such as roads, hospitals or schools.
“All of these projects would create jobs.”
He added that the cost of the project…