Treasury's latest IRA guidance is likely to revive grappling about what qualifies as "clean" energy, Nick writes.

Why it matters: The Biden administration is trying to decide how to factor biomass and biogas into the IRA's tech-neutral energy tax credits.

• Its final guidance for the incentives will have implications for the running controversy about whether these fuels are climate-friendly.
• Some environmentalists want Treasury to shut these fuels out of the IRA.

Zoom in: Treasury's initial proposal, released last week, effectively punts on whether ​​fuels like biomass and "renewable" natural gas will qualify for the incentives.

• The law requires it to consider the life cycle emissions of burning or gasifying these fuels to make electricity. The administration set out a list of questions about how to model those emissions.
• That's likely to set off a letter and comment war, as industry and green groups clash over the future of these fuels.

Between the lines: It's not make-or-break for the industry. The credit isn't trying to create an industry from scratch, and RNG currently has limited scale in the power sector.

• Still, "there's just so many opportunities to take this industry and really kind of bring it to the next level," said Lauren Collins, a tax lawyer with Vinson & Elkins.

Treasury asked a similar series of questions about RNG in its initial proposal for the 45V hydrogen credit.

• In both cases, the RNG industry essentially wants the department to use a version of the GREET model to back up what it says is its "enormous climate benefit."
• "We are evaluating the opportunity to clarify a few issues and look forward to responding to broader questions" in the electricity credit guidance, Geoff Dietz, director of federal government affairs for the RNG Coalition, said in a statement.

The other side: Companies and state governments see these fuels as carbon-neutral. But Sarah Lutz, a climate campaigner at Friends of the Earth, argues that those evaluations are based on "very arbitrary or honestly incorrect baseline assumptions."

• "The main thing that we're advocating for is that Treasury is taking a really hard look at what the baseline assumptions are for their model and that they're not putting their blinders on," she said.

What we're watching: Hill progressives have already tried to stop biomass companies from getting the IRA's advanced manufacturing incentive.

• But RNG's got some bipartisan support. Rep. Linda Sanchez and Sen. Thom Tillis have legislation that would create a tax credit for RNG in vehicles and airplanes.

Battleground Democrats, led by Sen. Sherrod Brown, are calling on the Biden administration to investigate Chinese solar companies for alleged unfair trade practices, Axios' Hans Nichols and Stephen Neukam report.

Why it matters: Trade with China has emerged as a flashpoint in the 2024 election, with Biden and former President Trump competing with each other on whose approach is stronger.

• "Holding China accountable for its illegal trade practices will allow for the growth of a more diverse, and more secure, solar supply chain, here in the United States," Brown and other Democrats wrote in a letter to the Commerce Department and the U.S. International Trade Commission (ITC).

Driving the news: Major U.S. solar manufacturers in April filed a petition with Commerce and the ITC calling for a new investigation into solar panels imported from Cambodia, Malaysia, Thailand and Vietnam.

• The letter supports that probe into unfair subsidies and argues that the case "has the potential to set an important precedent for addressing China's anticompetitive practices across many industries."
• Brown is joined by Tammy Baldwin, Bob Casey, John Fetterman, Joe Manchin, Jon Ossoff and Jon Tester in the Senate.
• Marcy Kaptur and Jared Golden are among the signatories from the House.
• Claudia Tenney and five other House Republicans wrote a similar letter yesterday supporting the petition.

Flashback: The Commerce Department has already found that Chinese companies have used these four countries to skirt U.S. tariffs.

• That issue has divided Democrats for over two years, particularly after the White House in 2022 slapped a two-year pause on tariffs in that circumvention case.

What's next: That pause is scheduled to expire tomorrow.

• And the fresh investigation could have even bigger impacts for both domestic manufacturers and developers that want to put imported panels in the ground right now.

🎯 1. Powering up: Sen. Shelley Moore Capito filed a new CRA resolution today to toss out EPA's power plant emissions rules.

• She's joined by 43 other senators (including Manchin). Rep. Troy Balderson is leading the House version.

☀️ 2. No sunny day: The Sunrise Movement, the youth group that helped shape President Biden's 2020 climate agenda, is withholding its endorsement of him this year, Hans reports.

• White House climate adviser Ali Zaidi, asked about Sunrise's move at a Politico energy forum this morning, responded: "There's a gap between where we are today and where we need to go, and the only way we get there is by accelerating the pace of action.… And I think they couldn't have a better partner than Joe Biden in doing that work."

💸 3. It begins: The House today narrowly passed its first fiscal 2025 spending measure: the milcon-VA bill.

• It was a largely partisan vote, which suggests that the energy and environment bills will be much the same again this year.