With climate change attracting increasing public and Congressional attention, some Democrats are flirting with an idea that puts them odds with many of their environmental allies: turning to nuclear power to generate electricity without producing greenhouse gases.

Already this year, several prominent Senate Democrats, including presumptive 2008 presidential frontrunners, Sens. Hillary Rodham Clinton (N.Y.) and Barack Obama (Ill.), are backing legislation that would boost nuclear energy through federal subsidies, even though environmentalists have soundly criticized such measures.

In the meantime, Speaker Nancy Pelosi (D-Calif.) raised eyebrows earlier this month when she told the House Science and Technology Committee that she is open to considering nuclear power as an option to combat climate change.

“The technology has changed … I bring a more open mind to that subject now,” Pelosi said at a Feb. 8 hearing on climate change. “I have a different view of nuclear energy than I did, say, 20 years ago when I came to Congress.”

While cautioning that she would not be “an active proponent” of nuclear power, she added that it “has to be on the table,” especially when considering the huge quantities of carbon dioxide-emitting coal that countries such as India and China burn to create electricity. “The alternative may be nuclear,” Pelosi said.

Nuclear proponents, including the industry’s trade association, the Nuclear Energy Institute, welcomed Pelosi’s statement.

“We certainly appreciate the fact she is willing to take a second look,” said NEI spokeswoman Trish Conrad. Nuclear’s potential to provide significant amounts of electricity, combined with its zero greenhouse emissions, is directing increased attention to the industry, Conrad said.

In addition, other Senate Democratic leaders, including Environment and Public Works Chairwoman Barbara Boxer (D-Calif.) and Sen. John Kerry (D-Mass.), have acknowledged the growing momentum for nuclear in recent weeks, although neither has expressed support for the sector.

The nuclear industry has long been haunted by the disasters at Three Mile Island and Chernobyl, which fanned public safety fears over nuclear meltdowns. In addition, concerns over safely disposing of the plants’ highly radioactive waste, as well as fears of nuclear proliferation, also helped stymie industry efforts to expand for the past two decades.

While the nuclear industry has supporters on both sides of the aisle, Democrats generally have been more critical of the nuclear industry than Republicans, in part because of the party’s historically strong connection to the environmental movement.

But increased attention to climate change is altering the dynamics of nuclear politics. Because they don’t produce greenhouse gases, nuclear plants are starting to appear more attractive than they once were to policymakers — or at least the lesser of environmental evils when compared to burning fossil fuels.

Environmentalists, however, adamantly deny that Democrats are undergoing a nuclear renaissance.

Michele Boyd, legislative director of Public Citizen’s energy program, describes as a “myth” the notion of Democrats flocking to nuclear power, even though some have, especially those from states that derive much of their power from nuclear sources.

Michael Mariotte, executive director of the Nuclear Information and Resource Center, emphasizes neither political party has ever been unified on nuclear power.

“On both sides of the aisle, you’ll find widely divergent views on nuclear,” said Mariotte, who describes many Senators as “skeptical of nuclear power but not opposed.”

The Democratic National Committee did not respond to requests for comment on the party’s nuclear views. But in an energy policy paper released last year, the Progressive Policy Institute — affiliated with the Democratic Leadership Council, an independent group for centrist Democrats — called for the expansion of nuclear power, arguing that new designs for nuclear plants will eliminate long-standing safety concerns.

A number of Democratic senators have signed on to a global warming bill authored by Sens. Joe Lieberman (ID-Conn.) and John McCain (R-Ariz.) — a bill that includes subsidies for building new nuclear power plants. Such subsidies have attracted fire from environmentalists. In fact, during the 109th Congress, the inclusion of similar incentives cost Lieberman and McCain some Democratic support for an earlier version of the bill

So far, six Democrats are co-sponsoring the bill this session, including Clinton, Obama, and Majority Whip Dick Durbin (Ill.).

Environmentalists, who are encouraging lawmakers to subsidize renewable energy sources and clean energy instead, add that the nuclear incentives in the bill are redundant, noting that Congress in 2005 passed an energy bill that contains numerous federal subsidies to boost nuclear generation.

Environmental groups are also unhappy with a climate-change proposal introduced by Sens. Dianne Feinstein (D-Calif.) and Tom Carper (D-Del.) that allows nuclear utilities to accumulate credits under a cap-and-trade system if they reduce carbon dioxide emissions. Critics say the plan would promote expanded power generation at the expense of safety.

For their part, Boxer and Kerry are promoting separate bills on climate change, neither of which include incentives for nuclear. While Kerry isn’t closing the door to nuclear, a spokesman said that the senator is “generally not too supportive of it because of waste concerns,” and would rather see “more work on the other areas first,” including renewable resources such as wind and solar energy.

A spokesman for Boxer noted her long-standing concerns over nuclear safety.

The environmental community as a whole, however, remains opposed to nuclear power. “We’re extremely persuaded that the problems that nuclear faces are very significant,” said Geoff Fettus, an attorney with the Natural Resource Defense Council’s nuclear program. He and other opponents cite the high costs of nuclear energy, proliferation concerns and disposal challenges as reasons to oppose federal subsidies to encourage nuclear power.

Providing incentives, Fettus said, would be “throwing more money down the nuclear drain.”