Only an hour before President Obama is expected to deliver his State of the Union address—in which he might “go big” on the issue of combating climate change—two Senators announced they will introduce comprehensive climate change legislation this week, presenting a possible vehicle in the Senate for Obama’s ambitions.

Senators Bernie Sanders and Barbara Boxer will outline the legislation on Thursday morning. Details are scant, though it’s being billed as “major” and “comprehensive” legislation, and will have a carbon tax, per a statement from Sanders’s office:

Under the legislation, a fee on carbon pollution emissions would fund historic investments in energy efficiency and sustainable energy technologies such as wind, solar, geothermal and biomass. The proposal also would provide rebates to consumers to offset any efforts by oil, coal or gas companies to raise prices.

Boxer is the chair of the Senate Committee on Environment and Public Works, so this is not a fringe effort by any means. And some heavy environmental and institutional groups will be on hand Thursday, including Bill McKibben of and representatives from the Center for American Progress, Sierra Club, Public Citizen, and the National Community Action Foundation.

We reported last month that Senator Sheldon Whitehouse and Representative Henry Waxman launched a Congressional task force, which aims to push the executive branch on new regulations, and to serve as a laboratory for new legislation—and while it’s not clear if Boxer is acting through this working group, the legislation is clearly ready to go.