Vice President Kamala Harris gives remarks alongside President Joe Biden on Sept. 13, 2022, at an event celebrating the passage of the Inflation Reduction Act at the White House. Source: Anna Moneymaker/Getty Editorial via Getty Images.

The 2024 US presidential election marks a pivotal moment for the ambitious suite of climate and energy regulations advanced by the Biden-Harris administration.

Executive branch agencies are defending broad controls on greenhouse gas emissions from the US electricity, transportation, and oil and gas sectors following a tie-breaking vote in 2022 by Vice President Kamala Harris for the Inflation Reduction Act, a historic $370 billion in energy and climate funding. The law's incentives, such as clean energy production and investment tax credits and a $7,500 federal tax credit for electric vehicle purchases, have been cited repeatedly by Biden administration agencies in documents supporting major energy and climate rules.

Former President Donald Trump's campaign, by contrast, is promising a spree of deregulatory actions centered on "energy dominance," with plans to dismantle the Biden team's sweeping climate agenda.

EXPLORE: Our 2024: The Year of Elections page provides more coverage of the US elections' potential impacts on the risk landscape and policy environment.

While the Biden administration sought to protect new emissions-cutting rules from quick reversal by finalizing many ahead of a murky Congressional Review Act deadline, the final rules remain vulnerable to rulings by conservative judges even if Harris denies Trump, the Republican presidential nominee, a second term.

"It often takes the first term for an administration to create regulations and the second term to defend them in court," said Tim Fox, a managing director at ClearView Energy Partners.

"A lot of what the Biden administration hoped to accomplish, they didn't get out the door as quickly as they had hoped so that it will get through the judicial process," added Christi Tezak, senior director at ClearView.

If Harris, now the Democratic presidential nominee, prevails, policy analysts expect her administration to focus on defending Biden-era rules from legal attacks and securing Inflation Reduction Act funding. A Harris administration is also expected to complete unfinished greenhouse gas rules, such as emissions limits for existing gas-fired power generators.

Most major Biden climate regulations are facing appeals from industry groups or red states that have yet to reach their legal conclusion.

In April, the Environmental Protection Agency finalized a rule requiring 90% carbon capture at existing coal plants by 2032, and in June, the US Transportation Department published final fuel economy standards requiring new cars and light-duty trucks to achieve a fleetwide 50.4 mpg by 2031. Those rules are still in early litigation.

On a scale of one to 10, Anna Mosby, a senior research analyst with S&P Global Commodity Insights, said she would put the regulatory risk and uncertainty for energy companies overhanging the election at a 12.

"With different presidents, we've seen a complete seesaw effect in terms of regulations," Mosby said. She said this "induces a ton of regulatory uncertainty" for companies that don't know which rules will stick.

Fresh wave of regulatory rollbacks

If voters return Trump to office, policy experts expect the new administration to seek voluntary remands for Biden-era regulations facing court challenges. That would kick off a process of overhauling or, in some cases, repealing the rules, as agencies have done during both the first Trump administration and Biden's presidency.

Joseph Brazauskas, senior counsel at the law firm Bracewell, said he would expect Trump to sign multiple executive orders on his first day in office, including an order directing the US government to focus on energy dominance and supporting traditional fuels such as gas, coal and liquid motor fuels.

Plans to re-exit the Paris Agreement on climate change, repeal and replace EPA regulations, and boost oil and gas leasing plans could all be announced in the Trump administration's early days, as could directives to swiftly nix the US Energy Department's pause and study of LNG export determinations and to open areas in Alaska to drilling.

A second Trump administration would likely seek to speed those plans by installing political appointees who are ready to implement pre-drafted policies, Brazauskas said.

"They may have Day One executive orders that are already written; they may have regulatory packages that are more ripe for implementation than previously in 2017, where things were a little bit more chaotic," Brazauskas said.

Former Trump administration officials have signaled the former president would begin taking action immediately.

"On Day One, President Trump will rescind every one of Joe Biden's industry-killing, job-killing, pro-China and anti-American electricity regulations," David Bernhardt, Trump's former Interior secretary, told reporters on an Aug. 29 campaign call.

That pledge generally aligns with recommendations in Project 2025, a 900-page deregulatory policy blueprint released by the conservative Heritage Foundation in anticipation of a future Republican presidential administration. Trump has tried to disassociate himself from the plan.

Energy Innovation, a nonpartisan energy and climate policy firm, estimated that full implementation of Project 2025's recommendations would put the US on track to fall 27 percentage points short of its Paris goal to reduce greenhouse gas emissions by 52% below 2005 levels by 2030.

"On greenhouse gas emissions, the biggest difference is coming from the power sector," said Robbie Orvis, Energy Innovation's senior director of modeling and analysis.

The latest update to S&P Global Commodity Insights' North American Power Market Outlook Planning Case anticipates a 52% reduction in US power-sector carbon emissions from 2005 levels by 2030 driven by clean energy tax credits in the Inflation Reduction Act. The planning case does not account for the EPA's recently finalized greenhouse gas regulations, which are seen as particularly vulnerable to litigation.

Some Biden agency rules may be at risk for early Congressional Review Act disapproval if Republicans sweep the White House and both houses of Congress. The Congressional Research Service unofficially estimates that rules finalized on or after Aug. 1 could be subject to congressional disapproval resolutions under the statute.

Rules at risk of disapproval include a yet-to-be-finalized methane fee regulation for the oil and gas sector, along with final Treasury Department tax credit guidance for clean hydrogen production.

Looming legal uncertainty

One of the biggest unknowns for a future Harris or Trump administration is how federal courts will decide legal challenges to agency rules following the US Supreme Court's decision in June to overturn the 40-year-old Chevron doctrine.

In that decision, Loper Bright Enterprises v. Raimondo, the high court's 6-3 conservative majority held that federal judges should independently interpret ambiguous statutes rather than deferring to an agency's reasonable interpretation.

"Courts and the judicial system's influence over energy and environmental policy, that's really the wild card, as a result of the fall of the Chevron doctrine and some of the court decisions around that," said Lesley Jantarasami, managing director of the energy program at the Bipartisan Policy Center.

Rushed procedural actions by new political appointees could exacerbate legal risks, and either new administration may face heightened scrutiny over compliance with the Administrative Procedure Act in the absence of Chevron, legal experts said.

The Supreme Court in June 2022 also established the major questions doctrine, a conservative line of legal thinking, as the law of the land. The doctrine holds agencies must point to clear congressional authorization when regulating on matters of "vast political or economic significance."

Jason Schwartz, legal director for the Institute of Policy Integrity at the New York University School of Law, said some lower court decisions dealing with agency rules could hinge on who appointed the presiding judges.

"There are statutes that Congress wrote that are pretty stringent, just from the plain language," Schwartz said. "If you're not going to give agencies any flexibility, that could result in some pretty aggressive outcomes."

Schwartz noted that Trump-appointed judges could be particularly receptive to using the major questions doctrine to attack agency rules. "Overall, I am worried about the potential to continue to use the judiciary to attack and further erode the authorities of administrative agencies," he said.

Environmental groups are already mobilizing to defend Biden-era energy and climate regulations if Trump retakes the White House.

"Should another administration come in and have a posture of rolling that progress back, whether it's at the behest of industry polluters or anyone else, we will engage in defense of that progress through every means under the law that we have at our disposal," said Chris Espinosa, legislative director for climate and energy at advocacy group Earthjustice.