Exelon Corp. says it will shut down the Clinton and Quad Cities nuclear plants. The utility cites what it says was a "lack of progress on Illinois energy legislation."

The Clinton Power Station in Clinton, Ill., will close on June 1, 2017. The Quad Cities Generating Station in Cordova, Ill., will close on June 1, 2018. Exelon says that Quad Cities and Clinton have lost a combined $800 million in the past seven years, despite being two of its best-performing plants.

The two-unit, 1,871 MW Quad Cities station.Quad Cities is a two-unit nuclear power plant powered by two General Electric boiling water reactors that give the plant a total electric capacity of around 1,871 megawatts (MW). The Clinton station is a single unit GE boiling water reactor with a generating capacity of 1,078 MW.

The single-unit, 1,078 MW Clinton nuclear station.The utility says that the path forward for consideration of so-called "Next Generation Energy Plan" legislation is not clear. As a result, Exelon says it has begun taking steps to shut down the plants. These include:

• Making permanent shutdown notifications to the Nuclear Regulatory Commission within 30 days
• Terminating capital investment projects required for long-term operation of Clinton and Quad Cities
• Immediately taking one-time charges of $150 million to $200 million for 2016, and accelerating approximately $2 billion in depreciation and amortization through the announced shutdown dates
• Cancelling fuel purchases and outage planning.

U.S. Energy Secretary Ernest Moniz called the growing number of closures of nuclear reactors in competitive, deregulated markets a “huge problem.”

“The importance to incentivizing continued operation [of nuclear plants], I think, is very clear, but the solutions are less clear,” Bloomberg quoted Moniz as saying at a May 19 Energy Department summit titled “Improving the Economics of America's Nuclear Power Plants.” The economics challenging existing nuclear plants in competitive markets, which are leading to early plant retirements, have unintended consequences of shutting down some of the most reliable, carbon-free baseload generation in the country, Moniz reportedly said.

Nuclear Energy Institute President and CEO Marvin Fertel says that 15 to 20 reactors are at risk of premature shutdown over the next five to 10 years. NEI says that five reactors have closed "prematurely" in the past few years, and companies have announced plans to close three more—FitzPatrick, Pilgrim and Oyster Creek. Collectively, NEI says these eight reactors would avoid 25 million short tons of carbon emissions annually, assuming all that generation were replaced with new natural gas combined-cycle power plants.