For more than a year, Connecticut legislators have been working to craft a policy to ensure that zero-emission electricity from the Millstone Nuclear Power Station continues to flow until at least 2035 and 2045, when its operating licenses expire.

Millstone, New England’s largest power plant, supplied 45 percent of Connecticut’s in-state power generation and nearly all its carbon-free electricity last year. With around 2,100 MW of installed capacity, the facility generates enough power each year to meet the needs of nearly 2 million Connecticut households. Moreover, the two reactors help avoid the emissions of more than 6 million metric tons of carbon dioxide per year.

But Millstone, like other nuclear power plants, faces economic headwinds. Challenges include sustained low natural gas prices, declining renewable energy costs, slow growth in electricity demand, and power markets structures and policies that don’t compensate nuclear for its environmental and reliability attributes. Mandated safety enhancements and other capital and maintenance investments are adding to plant costs. Since late 2012, six U.S. nuclear reactors have been retired prematurely, and seven more are set to close by 2025.

If this trend continues or accelerates, there could be serious climate implications. Nuclear power supplies 20 percent of total U.S. electricity, but makes up 57 percent of zero-carbon electricity. As all recent U.S. nuclear retirements have led to increased fossil fuel-fired generation, any additional loss of nuclear generating capacity would be expected to increase U.S. emissions of carbon dioxide as well as nitrogen oxides. These increased emissions will set back our efforts to fight climate change and regional air pollution. Although nuclear power enjoys bipartisan support in Congress, a federal remedy has failed to emerge, so individual states are taking action. Last August, New York established a clean energy standard to help assist its upstate reactors. In December, Illinois passed a law to support two (i.e., Quad Cities and Clinton) of its six nuclear power plants in a similar fashion. New Jersey, Ohio and Pennsylvania are exploring options to support their nuclear reactors.

In Connecticut, lawmakers have proposed creating additional opportunities for Millstone to sell its power. In the bill’s current form, nuclear power would be able to participate in a state solicitation for carbon-free power. Under this arrangement, the commissioner of the Department of Energy and Environmental Protection could direct electric distribution companies (i.e., utilities) to “enter into agreements for energy, capacity, and environmental attributes,” provided the proposals are in the best interests of the ratepayers and meet other criteria. At the same time, the bill would increase the state’s renewable portfolio standard (RPS) to 40 percent by 2040 from 27 percent by 2020. So as not to overwhelm the RPS and inhibit the growth of renewables, only a portion of Millstone’s output should be eligible under the final bill unless the ambition of the RPS is increased commensurately.

To remain economically viable, power plant owners rely on revenues (i.e., energy and capacity) they receive from participating in wholesale power markets. However, low natural gas prices continue to put downward pressure on wholesale electricity prices across the country. In 2016, prices in New England’s electricity market averaged $28.94/MWh – the lowest since the market was established in 2003 and below the average total generating cost for multi-unit nuclear reactors. Owners can also enter into two-party agreements directly with power consumers or other parties. While this offers an alternative revenue stream, these contract prices tend to reflect current circumstances in electricity markets.

Power markets are challenging and do not reward nuclear power for its large environmental and system reliability benefit. In the absence of a price on carbon, we need alternatives to ensure nuclear power plants do not retire prematurely. We applaud Connecticut’s proactive approach to recognizing the carbon-free attributes of New England’s largest power source. State leadership on climate has never been more critical. With reasonable policies in place to maintain the existing U.S. nuclear fleet, it will be easier for the U.S. to reduce its emissions and achieve its climate and air pollution reduction goals.