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Al Gore’s Alliance for Climate Protection began flooding the cable news networks Thursday with a TV spot (subscription) that attacks the oil industry for lobbying against renewable energy legislation.

“Why are we still stuck on dirty and expensive energy?” the narrator asks as the camera pans over an offshore oil rig followed by a suitcase full of cash. “Because Big Oil spends hundreds of millions of dollars to block clean energy.”

Donations to keep the ad running started pouring in even before the spot aired: Within six hours of e-mailing the video to its members, the group said, they raised $150,000 in contributions.

While "Big Oil" remains a favorite villain of political advertising, the spot comes at a time when momentum is growing for increased domestic drilling: The House voted this week to allow oil exploration offshore, a conservative group recently hit the airwaves with pro-drilling spot and the battle cry "drill, baby, drill" is now part of the country's political lexicon.

But there are also encouraging signs for advocates of renewable energy, including broad public support for wind and solar and measures in the House drilling bill that would incentivize alternative energy and roll back subsidies for oil companies. The Alliance isn't alone blaming K Street for holding back a shift away from fossil fuels.

“The technology is there," said Mark Jacobson, a professor of civil and environmental engineering at Stanford University. "The problem is lobbyists for other technologies -- nuclear, coal, biofuels -- that don’t do what they claim.”

And, he warned, don't expect John McCain or Barack Obama to change the status quo.

"You look at the presidential candidates, one is pushing biofuels, which are a joke," Jacobson said of Obama. "And the other is pushing nuclear power, which is a danger to American national security.”