During a Senate hearing on clean energy earlier this week, Republicans Lamar Alexander and Mike Crapo caused a minor stir by hinting that maybe, just maybe they'd consider the idea of a climate bill with a cap-and-trade program for carbon emissions—as long as the bill had strong support for nuclear energy.

What sort of support? Alexander mostly just reiterated the GOP preference for building 100 new nuclear power plants (how that would actually get done was left unclear). Crapo, though, had a more concrete suggestion: He said he wants to revise the renewable-electricity standard (RES) in the House climate bill so that electric utilities would be able to meet their targets by building nuclear plants as well as wind, solar, geothermal, and other renewables.

It's not clear what Crapo has in mind, exactly. Right now, the House RES already accommodates nuclear power to some extent. Here's how it works. Each year, utilities calculate their total generation—the baseline—and then have to get a certain fraction of that from renewables and efficiency. (The targets keep increasing until, by 2020, utilities have to get 15 percent of their power from renewables and 5 percent from efficiency, or 12 plus 8 with a waiver.) But there's a catch. If a utility builds a new nuclear plant, they can deduct that power from the overall baseline number. In other words, building new nukes won't help utilities meet their renewable targets, but it can reduce the absolute amount of renewable energy utilities have to purchase.

Some politicians want to go even further than that. During the House debate, a few proposed (and defeated) amendments would've allowed utilities to count existing nuclear power toward the standard. But this would render the RES completely meaningless, since nuclear already accounts for roughly 20 percent of U.S. electrical power generation—if those amendments had passed, utilities wouldn't have to buy any credits from wind or solar farms at all. If that's what Crapo has in mind, it doesn't make much sense.

A third option would be to allow new nuclear plants to count toward the standard. In theory, this could water down a measure that's already unlikely to give much of a boost to the renewable-power industry. Marchant Wentworth of the Union of Concerned Scientists says that given all the current loopholes in the House RES, the provision, as it stands, isn't likely to expand U.S. renewable-power generation much beyond what state-level efforts are already projected to do.

In practice, though, adding nuclear to the RES might not actually matter much. "I don't think there would be substantial harm to the 2020 renewable electricity standard," Wentworth says, "because of the prohibitive costs [of nuclear] and the time required for the plants to come online." Right now, the federal government is the only party willing to offer what have historically been quite risky loans for the construction of new nuclear plants and, barring a major scale-up of the government's $18.5 billion existing program, it's unlikely that a bunch of new projects will start breaking ground. Utilities would probably stick with wind and solar projects to meet the RES anyway.

The other question, meanwhile, is whether a nuclear concession would actually attract votes. Alexander and Crapo haven't explicitly said they'd agree to a quid pro quo deal—at this point, that's all just speculation.