This Oct. 8, 2015 photo shows the FitzPatrick nuclear plant in Scriba, N.Y. (Stephen D. Cannerelli/The Syracuse Newspapers via AP)

In June, the state of California — which has led the U.S. in putting electric cars on the road and switching to so-called clean electricity — took a decisive turn in its quest to move away from carbonemitting fuels. An agreement between the large utility Pacific Gas and Electric and environmental and labor groups set a path for retiring the Diablo Canyon nuclear plant, and thus, for a state in which “carbon free” will not include energy generated through the splitting of atoms.

On Monday, though, New York — also a leader when it comes to greening power supplies — announced a very different route. The state’s Public Service Commission approved a Clean Energy Standard backed by Gov. Andrew Cuomo’s backed Clean Energy Standard. It seeks to get New York to 50 percent renewable electricity by the year 2030 — while also retaining the six nuclear reactors that currently provide more 30 percent of the state’s electricity. (These reactors would not count as part of the renewable 50 percent.)

“Maintaining zero-emission nuclear power is a critical element to achieving New York’s ambitious climate goals,” a statement from Cuomo’s office said. The new Clean Energy Standard includes a requirement that nuclear energy be valued in the marketplace for not producing carbon emissions, thus requiring utilities to pay for “Zero-Emission Credits” when using nuclear.

“This will allow financially-struggling upstate nuclear power plants to remain in operation during New York’s transition to 50 percent renewables by 2030,” said the governor’s office statement. “A growing number of climate scientists have warned that if these nuclear plants were to abruptly close, carbon emissions in New York will increase by more than 31 million metric tons during the next two years, resulting in public health and other societal costs of at least $1.4 billion.”

The nuclear industry has been in a state of near-crisis in recent years as extremely cheap natural gas prices, in combination with tax subsidies for wind and solar, have provided difficult competition, triggering the closure of a number of plants across the country. Nuclear defenders have accordingly often called for a policy like New York’s, which in effect subsidizes nuclear in the marketplace by ascribing value to the fact that it does not fill the air with carbon dioxide, or with particulates that contribute to air pollution.

“This is 180 degrees different from the California path, which is limiting future operation of reactors through renewable portfolio standards that act to eliminate nuclear from the marketplace,” said Scott Peterson, a spokesman for the Nuclear Energy Institute. “By virtue of this policy, New York is retaining all carbon-free options by providing a clean energy standard that both incents the development of renewables and maintains 60 percent of existing carbon-free electricity from nuclear energy.”

The policy would initially benefit three nuclear plants that are “at risk of closure from market challenges,” added Matt Crozat, a member of the institute’s policy team. Those are the FitzPatrick plant owned by Entergy — which was scheduled to close late this year or early next year, but would now presumably be saved under the policy — Nine Mile Point, and the Ginna plant.

The credit would be paid to the plants by New York utilities who use their power, and who could then pass the cost of the credit on to power consumers. An analysis of the proposal, by the staff of the Public Service Commission, found that it might cost $965 million over a span of two years, but lead to a net benefit of around $4 billion due to the value of lower carbon dioxide emissions and less air pollution, among other benefits.

Still, many critics of nuclear energy persist, in the environmental community and elsewhere, and not all observers think New York necessarily made the right move.

“By not making them compete for a place in the low carbon portfolio, the state is almost assuring that the customers are going to pay more than they have to, and that some desirable alternative sources won’t get developed, because nuclear’s place in the picture is locked in,” said Peter Bradford, a former chair of the New York Public Service Commission and an adjunct professor at the Vermont Law School.

Some of the tension behind the move could be seen in a statement by the Natural Resources Defense Council, an environmental group that was a party to the California nuclear agreement. The group praised the New York policy overall but also noted that its nuclear portion could still be “adjusted up or down after 2018 based on market conditions; output from the nuclear plants will not count toward the 50 percent renewables mandate.”

“We look forward to working with Governor Cuomo and others to achieve and surpass the target well before 2030 to give New Yorkers a rapid and orderly transition to a truly sustainable and pollution-free energy future that moves beyond risky fossil fuels and nuclear power,” said NRDC’s Kit Kennedy, who directs the group’s energy and transportation program, in the statement.

All sides will now watch how these two experiments — in New York, and California — play out. Nuclear provides a major stream of what is often termed “baseload” electricity, which is continuous and thus very different from wind and solar, which are much stronger at key times (solar, for instance, in the afternoon) and less available at others. Thus, integrating more wind and solar with less baseload, as California aims to do, presumably puts a greater emphasis on the use of energy efficiency measures (less electricity use over all), or energy storage (using electricity at a different time from when it is generated), to deal with these sources’ intermittency.

In the meantime, though, the move was a happy one for climate scientists like James Hansen, who have argued that nuclear remains critical for achieving climate change goals and who criticized the California decision.

“What Governor Cuomo and the Commissioners did was an act of courage, putting the common good ahead of political expediency,” said Hansen. “Governor Cuomo, by banning fracking and supporting nuclear power, has put himself head and shoulders above other Governors, showing that he is able to make tough scientifically justified decisions for the benefit of the environment and the future of young people.”

Correction: This article previously referred to the Nine Mile Point nuclear plant as “Nine Mile Island.” That has been corrected.