What remains uncertain are both the details and whether any “poison pills” of the House version could still find their way into the final legislation that could dramatically limit supply chain materials or prevent small developers from participating in tax credits.

All of this is happening when the U.S. needs more power from any means necessary to satiate “unprecedented” rising electricity demand for the first time in decades, driven largely by the data center construction boom to power AI and more, said Exelon CEO Calvin Butler. Butler chairs the Edison Electric Institute representing investor-owned electric utilities nationwide and his company Exelon is No. 192 on the Fortune 500.

“We believe the [clean energy] tax credits are key,” Butler told Fortune in a June 26 interview. “We don’t believe you can get to the [U.S.] energy dominance without having renewables as part of the solution. That’s the all-of-the-above approach.”

Butler said the utilities association is “amenable” to the Senate version of the bill, even if the tax credits ideally would be extended for longer. “We’ll take what we can get,” he added. “We’re optimistic, but on top of it.”

Much of the GOP has sought to expedite oil and gas at the expense of renewables. Currently, the legislation is threatened by GOP infighting and a Senate parliamentarian ruling against taxation changes to Medicaid. The Inflation Reduction Act claw backs desired by a large portion of the GOP are just a small part of the unwieldy bill.

Of particular concern are provisions addressing both the “transferability” of tax credits—considered necessary by smaller and mid-sized developers to get many projects off the ground—and the “foreign entities of concern” (FEOC) provisions. The FEOC rules, which only applied to electric vehicle tax credits in the IRA, would now apply to all clean energy tax credits, essentially limiting needed supply chain materials from China.

Transferability, which is restored in the Senate bill for now, allows smaller developers to raise capital by transferring tax credits at a discount to larger buyers with greater tax liability that can immediately take advantage of the tax benefits. Eliminating transferability would hurt smaller developers that need extra optionality to raise capital.

The House version of the bill axed transferability after 2027, placed strict FEOC rules on all tax credits, did away with EV and residential solar tax credits, and required that new clean energy utility projects would have to break ground within 60 days of the bill’s signing and placed into service by the end of 2028—an impossibility for many hundreds of planned projects.

The pending Senate version restores transferability, keeps more lenient and phased-in FEOC rules on all tax credits, and allow clean energy projects to break ground through the end of 2027—potentially finishing after President Trump’s presidency. Residential solar and EV tax credits remain at risk.

“We believe the transferability is critical for significant development and growth in renewables,” Butler said.

For U.S. solar developer Avantus, CEO Cliff Graham said maintaining transferability is vital to the industry.

“If transferability goes away, it’s kind of a backdoor way to shut down the IRA,” said Graham, who’s currently developing solar projects in California, Nevada, and Arizona.

If transferability is maintained, the irony is the winding down of the IRA tax credits would speed up wind and solar construction projects, he said. “We’re in the queue. We’re already there. We can deploy in 18 months. Gas plants are years away for [hyperscalers].”

“You’re going to have an artificial stampede off all these people trying to get their [renewable] projects in on time,” Graham said, which will trigger supply chain shortages. “Equipment is going to get even more expensive.”

Roman Kramarchuk, head of climate market and policy analysis for S&P Global Commodity Insights, said he believes the foreign entities of concerns rules could prove the more problematic “poison pill” for the renewable industry, although the Senate version is again less onerous.

The biggest pain point Is utility-scale battery storage because China has a near-monopoly of many of the battery components.

“It’s really hard to imagine doing storage equipment without having elements of either battery cells or modules coming out of China,” Kramarchuk said. FEOC rules are the “hidden piece” of the legislation that “could really stifle the uptake of and use of the tax credits.” The “clearer definitions” in the Senate version are at least easier to deal with than the strict and vague FEOC rules in the House bill.

Instead of a total ban on Chinese materials, the Senate FEOC rules would phase-in supply chain restrictions, allowing developers to reduce their China-sourced materials each year on a set schedule.

As Graham said, the goal is always to use U.S. materials, but there isn’t enough domestic manufacturing yet and, even when there is, they will still have to source a lot of materials from China and elsewhere.

“We want to use as much domestic content as possible. There just isn’t enough today to be able to get done when needs to get done,” Graham said.