The leaders of the Senate Finance Committee are trying yet again to extend tax breaks for renewable energy, revealing on Thursday another attempt to break a long-standing logjam.

Chairman Max Baucus , D-Mont., and ranking Republican Charles E. Grassley of Iowa released a new tax package that will top $40 billion once revenue estimates are finalized.

“Here we are again,” said Baucus. “I’m starting to feel like Don Quixote, except I’m not jousting at windmills. I’m jousting for windmills.”

The measure includes tax incentives for carbon sequestration, plug-in hybrid vehicles, conservation, wind energy, solar energy, nuclear energy and biofuels. It would extend expiring provisions and create some new breaks as well, with the costs offset largely by higher taxes on the oil and gas industry.

Baucus and Grassley want to inject their proposal into an upcoming Senate debate on energy policy, and it could get added to a bill that would expand offshore drilling.

Baucus and Grassley have tried repeatedly over the past two years to assemble an energy tax proposal that can get through the Senate. The closest they came was in December 2007, when a vote to limit debate on their plan came up one vote short of the 60 needed.

The House has repeatedly passed energy-tax measures, only to see them stall in the Senate, where Republicans have resisted Democratic efforts to offset their cost.

Like the new Baucus-Grassley approach, previous versions have relied on revenue increases affecting the oil and gas industry. Grassley, who usually opposes offsets being used to extend existing tax policy, said this issue is different. “What we have done is used production incentives in one area of energy and move them to another area of energy,” said Grassley.

The renewable-energy industry continues to warn that failure to extend the tax breaks beyond their Dec. 31 expiration date will delay projects aimed at helping the nation shift away from fossil fuels.