Democrats on the House Energy and Commerce Committee have reached a deal on the most contentious aspects of cap-and-trade legislation for carbon emissions and plan to unveil the bill on Thursday, Chairman Henry Waxman (D-Calif.) said Tuesday night.

“We have resolved a good number of the issues,— Waxman said after a meeting with committee Democrats, adding that the bill remains on track to clear his panel next week. Opening statements are planned for Thursday with a marathon markup beginning on Monday.

“I am optimistic. I believe we will have the votes to pass the bill [next week],— Waxman said.

Waxman had to compromise with Rep. Rick Boucher (D-Va.) on one of his key goals —the overall level of carbon reductions by 2020. Waxman had wanted a 20 percent cut; Boucher has worried such a steep cut would outpace the development of new technologies like carbon capture from coal-fired power plants. They settled on a 17 percent cut instead.

Waxman also agreed to give utilities free initial allocations on nearly all of their emissions. Boucher had sought to give utilities the credits to avoid rate hikes for consumers.

The Energy Committee chairman added that details have not yet been worked out on all of the allocations, including those for refineries, but said he expected that they would be reached quickly.

A smiling Boucher also acknowledged that some details still need to be completed. “It’s still a work in progress,— he said.

Members also reached a deal on renewable electricity requirements. Energy and Environment Subcommittee Chairman Ed Markey (D-Mass.) said the legislation would require that 15 percent of electricity be renewable by 2020, although up to 8 percent could come from efficiency measures.

The agreement also includes additional help for automakers on top of the “cash for clunkers— provision announced last week at the request of Rep. John Dingell (D-Mich.).