New York state is forging ahead with hundreds of miles of new high-voltage power lines, the kind of push that clean-energy advocates would like to see copied nationwide.

Long-distance transmission is an essential if unglamorous part of strategies to replace fossil-fuel power plants with non-emitting sources. Large solar and onshore wind farms sit on rural land and need a conduit to energy-hungry cities.

Targeting 70 per cent renewable electricity by 2030, New York has one of the most aggressive climate laws in the US. It could provide a template for Joe Biden’s plan to remove carbon from US power by 2035. The president-elect picked New York climate policy chairman Ali Zaidi as his deputy national climate adviser, a sign of the state’s influence.

Last week New York opened bidding for at least three transmission projects including a 330-mile line running from the Canadian border to New York City. Other projects breaking ground this year will add the first major new transmission lines since 1978, said Gil Quiniones, chief executive of the New York Power Authority, a state-owned utility.

“This buildout is just unprecedented,” he said. “The sheer amount and magnitude of these transmission projects will completely change the grid.”

More power lines are a priority for renewable energy advocates. A study by Americans for a Clean Energy Grid, an industry coalition, found that expanding transmission in the eastern US would stoke growth in wind and solar generation and drive customer bills down a third by 2050.

In New York, almost 90 per cent of the electricity consumed upstate already comes from zero-carbon sources such as hydropower, nuclear, solar and wind, according to the New York Independent System Operator (Nyiso). But congestion on the way to New York City means that fossil fuels generate 69 per cent of its electricity.

“If the state is going to satisfy the renewable energy mandates that are in the law, transmission absolutely has to be built out,” said Conor Bambrick, director of climate policy at Environmental Advocates NY.

But long-distance transmission towers have often been fought by landowners and states that do not stand to benefit. New York’s projects lie within its borders, but the state also contains “dense, complicated, populated regions,” Andrew Cuomo, New York’s governor, said in a speech last week. “Building transmission capacity is not as easy as it sounds.”

One solution is to put offshore wind farms in the ocean, away from homes and connected to land by an undersea cable. New York last week awarded the Norwegian energy company Equinor and its partner BP contracts to develop two wind projects totalling 2.5 gigawatts of capacity in waters off the Atlantic coast.

Onshore, New York is trying to avoid conflicts by installing new wires in existing transmission corridors or burying them. The capacity will be necessary as “the existing transmission grid would be overwhelmed by the significant renewable capacity additions” that are planned, the grid manager Nyiso concluded in a study. Last week alone the state awarded contracts to 21 solar projects totalling 2.1GW within its borders.

A 1.2GW transmission line proposed by LS Power, an independent power producer, would run underground and under the bed of the Hudson river from the Catskill Mountains to New York City.

“It will have the ability to catalyse and unlock a lot of the shut-in renewables” upstate, said Clint Plummer, chief executive of LS’s Rise Light & Power subsidiary. “There’s a great deal of wind and solar that simply need to access customers.”

Blackstone, the private equity group, owns a company that a decade ago proposed the Champlain Hudson Power Express line to deliver 1GW of power from Canadian dams to New York City. The project’s 330-mile path matches the one described by state officials, though it has not been officially endorsed.

Blackstone-owned Transmission Developers and Hydro-Québec said the project was permitted and ready to begin construction this year. “The combination of clean energy with carefully sited transmission promises to reduce harmful pollutants and the city’s dependence on fossil fuels, while creating thousands of jobs for New Yorkers,” the companies said.

Canadian hydropower would compete with power plants inside New York. The Independent Power Producers of New York association has attacked the project, releasing a report with the environmentalist Sierra Club which claimed that Champlain Hudson would divert Hydro-Québec’s electricity from other markets and fail to reduce emissions. Hydro-Québec is also poised to send 1.2GW to Massachusetts after the utility Avangrid began construction last week on another new transmission line through the woods of Maine.

Transmission Developers and Hydro-Québec rebutted the report, arguing that New York’s independent power producers lacked credibility because their fleets included units fired by natural gas.