The largest nuclear utility in the country says it will work to keep its nuclear fleet open to face the challenge of climate change, while fighting bad federal and state policies that could force its zero-emission power plants to close.

"For the good of our employees, our customers, our communities and the climate, we will keep working for solutions in all of our states to preserve zero-carbon nuclear generation and promote the advancement of clean energy," said Chris Crane, Exelon Corp.'s president and CEO. "But where we can't see a path to sustained profitability, we have no choice but to shut down plants."

The company said it will remain focused on "advancing policy and market reforms to preserve nuclear plants facing economic challenges as a result of sustained low natural gas prices and policies that do not value nuclear for its reliability and zero-carbon benefits," the company said.

State renewable energy mandates do not consider nuclear power plants as a clean energy source, which is driving the market away from power plants that provide 24-hour-a-day electricity and toward more intermittent wind and solar energy.

At the same time, federal renewable energy subsidies are distorting the electricity market and making it harder for nuclear plants to recoup the cost of producing power. Exelon announced earlier this year that it would close two of its nuclear power plants in Illinois due to market factors and the state's unwillingness to assist it.

In addition, some members of Congress have begun accusing the Environmental Protection Agency of picking "winners and losers" by not crediting nuclear power as part of its new Clean Energy Incentive Program, which is meant to drive solar and energy efficiency development in support of its landmark climate rules, which are facing major court challenges.

"We see incredible opportunity in the years ahead as Exelon leads the transformation of our industry," Crane said. "We serve more utility customers and produce more clean energy than any other company nationwide, which gives us a unique platform from which to grow our business and invest in needed infrastructure and innovations to benefit our customers and communities."

Crane said the company will begin investing $25 billion on critical infrastructure, smart grid technology and other improvements to enhance grid reliability and customer service.

"These investments will drive utility earnings growth, representing a growing majority of Exelon's earnings through the remainder of the decade," the company said, placing emphasis on the earnings from its power plant fleet to help fund investments and reduce debt.

Exelon on Tuesday added to its nuclear fleet with the proposed purchase of Entergy's struggling James A. FitzPatrick power plant near Syracuse, N.Y., for $110 million. The purchase is expected to be approved by early next year. The decision to buy the plant comes a week after state regulators approved Democratic Gov. Andrew Cuomo's plan to add nuclear energy to the state's renewable energy mandate, requiring utilities to buy nuclear-generated electricity to meet the state's clean energy goals.

Cuomo praised Exelon's purchase of the plant. "This state cannot lose our supply of nuclear energy because it's important to keep the balance of supply," Cuomo said Tuesday. "So I believe the state has a moral obligation, financial obligation and a civic obligation to step in to this situation to avert a crisis for Central New York and to avert an energy crisis for this entire state."

He also said nuclear is necessary to avert a climate crisis from rising carbon dioxide emissions from burning fossil fuels that many scientists say are heating the Earth's atmosphere. "I believe this nation and this state needs a clean energy policy that is realistic and that can be implemented before we destroy this planet," Cuomo said. "And I believe that nuclear plays an important role in that clean energy policy."

He said nuclear will serve as a bridge to meet New York's target of having 50 percent of its electricity come from renewables by 2030.