Waterford — The Millstone Power Station generates $1.3 billion in annual economic output for Connecticut and another $1.3 billion annually for the rest of New England, according to the first report in over a decade to quantify the impact of the plant.

The Nuclear Energy Institute’s report was released Thursday morning, a week after the start of the new session in the General Assembly, which is expected to consider legislation to reduce the plant’s vulnerability to falling prices for the energy it produces.

The measure under consideration would allow Millstone owner Dominion Resources to sell its power directly to the state’s two main distributors, Eversource and United Illuminating, through contracts awarded through a bid process with big hydroelectric and other large-scale power producers. Currently Dominion sells the plant’s 2,111 megawatts of electricity generated at Millstone’s two operating reactors to third-party brokers.

State Sen. Paul Formica, R-East Lyme, has characterized the proposed legislation as his top priority for the current session. He could not be reached for comment on the NEI study.

According to the study, station operations are responsible for $873 million in annual economic activity in Connecticut. Another $402 million annually is provided to the state’s economy through wholesale electricity rates that are an estimated 12 percent lower than they would be if the plant were shut down and natural gas plants instead supplied the power produced by Millstone, the study said. The study attributed similar amounts of economic benefit from the plant to the rest of New England. Over the next 15 years, the plant would contribute an estimated $12 billion in economic output in Connecticut, the study said.

“What is unique about this study is that it quantifies the benefit of having lower cost electricity to consumers,” said Matt Crozat, senior director of business policy for NEI, an industry trade group. “What this report highlights is how deep the economic impact of Millstone is in Connecticut and more broadly. It’s underappreciated. It’s like a quiet soldier in the background.”

Ken Holt, spokesman for Millstone, notes that the report is being released the same week that plans to close the Indian Point Nuclear Power Plant in New York by 2021 were announced. Over the past four years, five other nuclear plants around the country have closed prematurely as the costs of operating older plants has exceeded revenues for the electricity they produce.

Holt said Dominion commissioned the NEI study to build support for the proposed legislation. It is the first study since 2003 to quantify the economic impact of Millstone, according to Crozat.

Holt said a second study being commissioned by Dominion is being done by The Analysis Group that specifically will examine energy market forces affecting the plant. The report is expected to be completed later this month. Both reports will be shared with key lawmakers, he said.

Along with the economic benefits, the study also quantifies the environmental impact of the plant in reducing emissions. Millstone produces its power without emitting greenhouse gases that contribute to climate change, preventing the release of 8.34 million metric tons of carbon dioxide — the amount released by about 1.9 million cars annually — in 2015, as well as avoiding the release of nitrogen oxide and sulfur dioxide. All three pollutants are released from plants that burn fossil fuels.

Other economic benefits attributed by the report to Millstone include:

• annual employment in Connecticut of 2,727 jobs in station operations, and 2,062 jobs from lower electricity prices.

• a reliable supply of 58.9 percent of Connecticut’s electricity demand, and 14.4 percent of demand for all of New England.

• about $40 million in annual state and local taxes.

j.benson@theday.com