He said Monday that he would get results, unlike those whom he said are bound by the unwritten rules and timidity of Washington politics.
"Our energy problem has become an energy crisis because no matter how well-intentioned the promise, no matter how bold the proposal, they all fall victim to the same Washington politics," Obama said.
He spoke at the new, energy-efficient Portsmouth Public Library, where about 100 invited guests watched a short video featuring every president since Gerald Ford promising to curb the use of fossil fuels - contrasted with a graphic illustrating the nation's increasing dependence on foreign oil. Obama suggested his rivals for the Democratic nomination would provide more of the same.
"There are some in this race who actually make the argument that the more time you spend immersed in the broken politics of Washington, the more likely you are to change it," he said. "I find this a little amusing."
Obama, who has been working to overcome suggestions that he's too inexperienced to be president, said those with long Washington careers have failed to act on issues such as higher fuel economy standards for cars and trucks.
"When they had the chance to stand up and require automakers to raise their fuel standards, they refused. When they had multiple chances to reduce our dependence on foreign oil by investing in renewable fuels that we can literally grow right here in America, they said no," he said.
"As president, I will set a hard cap on all carbon emissions at a level that scientists say is necessary to curb global warming, an 80 percent reduction by 2050," he said.
He proposed a modified "cap and trade" approach to reduce emissions, requiring businesses to buy allowances if they pollute, creating an incentive to reduce energy usage.
"No business will be allowed to emit any greenhouse gases for free," he said. "Businesses don't own the sky, the public does, and if we want them to stop polluting it, we have to put a price on all pollution."
Sen., D-N.Y., has said she is intrigued by the carbon auction system but has stopped short of endorsing it. Sen. of Connecticut has proposed taxing polluters for their carbon emissions.
Separate from the energy proposal, Obama joined rivalMonday in criticizing Clinton for voting for a Senate resolution that urges the State Department to designate Iran's Revolutionary Guard Corps a terrorist organization.
Edwards has said the resolution, which won overwhelming bipartisan support late last month, could give President Bush the authority to take the first step to war with Iran. New Mexico Gov.also has criticized Clinton's vote.
Obama joined them Monday.
"Senator Clinton and others should have learned from 2002 that if you give President George Bush a blank check that he'll cash it," the Illinois senator told The Associated Press after a campaign stop in Nashua. The reference was to the vote in Congress authorizing the use of force against Iraq.
"You've got to be very cautious and very sober regarding any kind of language or rationale that leads him to make more disastrous foreign policy decisions," said Obama. He did not vote on the Iran resolution because he was campaigning in New Hampshire.
Kathleen Strand, a spokeswoman for Clinton's campaign, responded: "It's unfortunate that Senator Obama is abandoning the politics of hope and embracing the same old attack politics as his poll numbers start falling."
On energy, Obama proposed using $150 billion from the sale of allowances to stimulate climate-friendly energy and economic development. Included would be developing the next generation of biofuels and fuel delivery infrastructure, accelerating commercial production of plug-in hybrid vehicles, promoting larger-scale renewable energy projects and low-emission coal plants, and making the electricity grid digital.
He also called for making government, businesses and homes 50 percent more energy efficient by 2030, with all federal government buildings carbon neutral by 2025. Incandescent light bulbs would be phased out by 2014, a measure Obama estimates would save consumers $6 billion a year on their electric bills.
"We are glad to see Senator Obama join this critical debate about how we keep our planet clean for generations to come," said Kate Bedingfield, a spokeswoman for Edwards, who several months ago released his plan to reduce greenhouse gas emissions at least 80 percent by 2050. Edwards would auction off a portion of the pollution permits and invest the proceeds on renewable energy technology and new jobs, while other permits would be sold or given away.