U.S. President Joe Biden hit the ground running Wednesday, with plans to sign a raft of executive orders to start the process of reversing Trump administration environmental and energy regulations and set the groundwork of what will be the federal government’s most aggressive effort to date to combat climate change. 

On the day of his inauguration as the 46th president, Biden turned to fulfilling a host of promises to take executive actions aimed at reducing the country’s greenhouse gas emissions and accelerating an already fast-moving shift from fossil-fuel-fired power plants to renewable energy resources. 

Biden’s “day one” actions included executive orders that will launch the process of reversing some of the Trump administration’s most “harmful actions” preventing the country from combating the climate crisis, domestic “climate czar” Gina McCarthy told reporters Tuesday. 

On the international front, Biden will formally resubmit the U.S. to the Paris climate agreement, which the U.S. officially exited in November under the direction of Donald Trump. The United Nations could accept U.S. membership in the international pledge within 30 days, beginning the process of repairing the rift between the U.S. and the majority of countries agreeing to its targets for carbon emissions reduction. 

The executive order will also seek to roll back oil and gas infrastructure projects opposed by the Obama administration and supported by the Trump administration. Those include rescinding federal permits for the Keystone XL pipeline project, which is designed to carry crude oil from the tar sands of Canada’s Alberta province to U.S. refineries, and halting oil and gas leasing in Alaska’s Arctic National Wildlife Refuge.

Trump’s decision to back out of the Paris accord, and his administration’s support of policies supporting the growth of fossil fuel industries, has not stopped the U.S.' shift away from coal and natural gas. The costs of wind and solar power have continued to fall over the past four years, and the pace of coal power plant closures has accelerated. 

As Biden takes office, renewable energy resources are expected to deliver 70 percent of the new generation capacity built this year, according to a new analysis from the U.S. Energy Information Administration. Batteries, which have also seen dramatic cost declines over the past four years, will supply another 11 percent of new capacity, the first time the rapidly growing technology has achieved a significant national market share. 

The U.S. utility sector has also made a dramatic turn toward clean energy since the exit from the Paris Agreement, bolstered by the economics of renewable energy and by state mandates and corporate demands for carbon reduction. In the past four years, most major U.S. electric utilities have committed to net-zero or zero-carbon emissions goals, most of them aimed at a 2050 target, and some seeking even more aggressive timelines. 

Next steps: Executive actions and legislation

But to reach Biden’s goal of zeroing out U.S. electricity sector carbon emissions by 2035, more aggressive action will be needed. Natural gas plants will make up only 16 percent of new capacity in 2021, according to EIA data. But natural gas remains the single largest source of electricity in the country, and almost all the utilities with zero-carbon pledges also plan to build more of them in the decade ahead. 

To meet this goal, the Biden-Harris administration is targeting a combination of executive actions and legislative proposals. On the executive front, plans include spending $400 billion on federal procurement of renewables, batteries and electric vehicles, reorienting federal government energy purchases on clean resources, ending fossil fuel leasing and smoothing renewable energy development on federally owned lands, and revising energy efficiency and vehicle fuel economy standards weakened by the Trump administration.

The Environmental Protection Agency could also regulate greenhouse gas emissions under the Clean Air Act, starting with the power sector. This week’s court decision vacating the Trump administration’s Affordable Clean Energy rule — the much weaker regulation that replaced the Obama administration’s Clean Power Plan — will allow the Biden administration to move more quickly on this front. 

Biden also plans to revive an interagency working group disbanded by Trump in 2017 that sets the “social cost of carbon,” a measure of the economic damage caused by the release of a ton of carbon dioxide into the atmosphere. A handful of states with aggressive decarbonization goals, such as New York, have used a calculation of the social cost of carbon in ways that boost the economic value of reducing emissions; changes to the federal benchmark value could combine with its use in policy to spur more aggressive action nationwide. 

Legislative actions will be more challenging but not impossible. The Jan. 6 runoff elections in Georgia delivered Democrats 50 seats in the U.S. Senate, giving the party a chance to pass laws over the objection of Republican senators with Vice President Kamala Harris casting the tie-breaking vote.

That could open up opportunities for Democrats to enact legislation supporting Biden’s $2 trillion clean energy and infrastructure investment plan. That plan includes boosting wind and solar power, energy storage, clean transportation and transmission grid investments. 

Republicans will be able to filibuster legislation in the Senate, but some of the aspects of Biden’s plan could be accomplished through the budget reconciliation process, which allows a simple majority to pass bills related to federal tax and appropriations policy.

Groups focused on the climate and energy crisis offered praise for Biden's early actions and laid out hopes for greater efforts to come. 

“The sweeping nature of these executive orders are an important down payment in addressing the tatters left behind by President Trump," Kathleen Rest, executive director at the Union of Concerned Scientists, said in a prepared statement. 

At the same time, the climate and energy crisis is just one of the most pressing issues facing the Biden administration in the weeks and months ahead, Rest noted, including "embracing the economic and public health benefits of renewable energy, modernizing the grid, increasing energy storage, electrifying our transportation system [and] incentivizing science-based farming practices to safeguard our food supply and farmers’ livelihoods. The plan must also invest in climate-resilient infrastructure, help frontline communities prepare for climate impacts and support a just transition for coal-dependent workers.”

Biden acknowledged the country's challenges in his inauguration speech. 

"We face an attack on our democracy and on truth, a raging virus, growing inequity, the sting of systemic racism, a climate in crisis, America's role in the world. Any one of these will be enough to challenge us in profound ways," he said. "But the fact is, we face them all at once, presenting this nation with one of the gravest responsibilities we've had." 

Also on Wednesday, Clean Energy for Biden, a group that helped raise $3.2 million in the 2020 election, said it would convert its efforts and form a nonprofit focused on future elections. Clean Energy for America plans an official launch in the spring, with an eye toward advancing a just energy transition by electing "clean energy and climate champions up and down the ballot."