(Bloomberg) -- Britain’s opposition Labour Party outlined plans to nationalize large swathes of the U.K. energy industry if it wins the next general election, a move that would put government in control of the grid for the first time since 1990.

The measures would put the companies that transmit power and own cables linking with markets in the European Union under the authority of ministers in London. Labour leader Jeremy Corbyn would make the priority to reduce fossil fuel emissions and ensure heat and electricity flow to consumers at lower prices.

Companies from SSE Plc to National Grid Plc, who have generated 13 billion pounds ($16.7 billion) in dividends for shareholders over the last five years, would be compensated with bonds at a price determined by Parliament. Prime Minister Theresa May’s government said the measures would cost 100 billion pounds and result in higher taxes. Labour said the plan would be “cost neutral” to the public purse and help those who are stretched financially to pay for fuel.

“Our plans see climate justice and social justice as inseparable,” said Rebecca Long Bailey, a Labour member of Parliament who speaks on business, energy and industrial strategy. “It’s an insult and an injustice to our people and our planet for companies operating the grid to rip customers off, line the pockets of the rich and not invest properly in renewable energy.”

While the next election isn’t scheduled until 2022, Prime Minister Theresa May’s grip of Parliament is fragile enough that lawmakers may opt to call a vote before then. Industry analysts think it’s unlikely Corbyn could achieve his ambitions even if he takes office.

“We do not believe that there is wider political support for the nationalization of regulated utilities,” John Musk, an analyst at RBC Europe Ltd., wrote in a note to clients. “Paying below market value may also damage investor sentiment towards the U.K. We also continue to question the economics of nationalization. The impact on national debt is not clear.”

The opposition says profit from the investor-owned networks will be redirected to build out the grid to support areas where there’s potential for solar, wind and tidal energy. Labour would create the National Energy Agency to own and maintain networks, while 14 regional agencies will take over from the current Distribution Network Operators. Additionally, municipal and local energy groups will be formed.

Labour wants to see the public ownership for the U.K. side of the five European interconnectors currently operation and the six that are either being built or planned.

Conservatives, who started selling state-run utilities when Margaret Thatcher was prime minister in the 1980s, bridled at the move, saying it would reduce investment needed to modernize the grid. The government has estimated it needs to draw in 100 billion pounds to replace aging coal and nuclear power stations and to modernize the grid for handling flows of renewable energy, which fluctuate with the weather.

“Corbyn’s ideological plan for the state to seize these companies would cost an eye-watering 100 billion pounds and saddle taxpayers with their debts,” said Chris Philp, a Conservative lawmaker.

Network operators cast doubt on how the plans could work. The idea of nationalizing the whole utility industry has been criticized as too expensive. The Centre for Policy Studies, a right-wing research group co-founded by Thatcher, estimated buying the Big Six and National Grid Plc would cost 124 billion pounds, and that would reach 185 billion pounds if the energy industry was nationalized.

Bloomberg Intelligence estimates the cost to be 135 billion pounds for buying the energy grids and water industry.

“Since privatization in 1990 network costs to the bill-payer have fallen by 17%,” David Smith, chief executive of the Energy Networks Association. “At the same time that costs have fallen, reliability has improved.”

In the last six years privately owned network companies have invested more than 22 billion pounds in gas and electric grids, Smith said.

To contact the reporter on this story: Jeremy Hodges in London at jhodges17@bloomberg.net

To contact the editors responsible for this story: Reed Landberg at landberg@bloomberg.net, Andrew Reierson

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