A marathon town hall centered on the climate crisis helped to paint in starker terms the major ideological differences dividing the Democratic Party on the issue. It also included wonkier questions such as how candidates would respond to rollbacks on lightbulb efficiency requirements.

Dropping behemoth climate plans has become a near-expectation in the 2020 Democratic field. Candidates pulled heavily from those documents Wednesday as Senators Bernie Sanders and Elizabeth Warren promoted the progressive policies in their Green New Deal-style plans, while front-runner and former Vice President Joe Biden offered up a moderate’s take on climate action.

But the 10 participating candidates — scheduled back-to-back for viewers with the stamina to watch for an entire seven hours — drew more nuanced lines between their climate and energy policies and those of their peers during the event, hosted by CNN.

While Biden wants to include nuclear, renewables and some fossil fuels in the net-zero emissions generation mix he envisions for midcentury, Sanders plans to transition to 100 percent renewables. Warren, who called her most recent policy drop “my plan for 100 percent clean energy,” clarified her position on Wednesday, noting that her administration would prohibit the build-out of new nuclear and phase out the technology by 2035 at the latest.   

Both Warren and Biden said they would consider a carbon tax as part of implementing their climate policies (Sanders has supported one in the past).

Controversy over Biden's plans to attend a Thursday fundraiser hosted by Andrew Goldman, a co-founder of natural-gas company Western LNG, consumed much of the former vice president's segment. Biden — who has signed a pledge refusing help from fossil fuel companies and executives — appeared confused about Goldman's position within the company. He also said he would not ban fracking but would review existing leases.

Biden's tack echoed that of Senator Amy Klobuchar, who said she would not ban fracking but plans to implement tough policies on methane leaks from the natural-gas sector. Senator Kamala Harris said she would support an end to fracking. Former HUD Secretary Julián Castro and Senator Cory Booker both said they would end fracking on public lands, while Warren and Sanders voiced support for nationwide fracking bans.

Though Warren and Sanders are regarded as the most left-leaning among Democratic 2020 contenders, the town hall illuminated some differences between the two as well. In a climate plan released in August, Sanders outlined plans to put electricity production in the hands of publicly owned power market administrations.

That’s not the approach Warren plans to take. She said she’s “not sure that’s what gets you to the solution" and provided assurance for a growing clean energy industry.

“I’m perfectly willing to take on giant corporations…but for me I think the way we get there is we just say, 'By 2035, you’re done. You’re not going to be using any more carbon-priced fuels,'” she said on Wednesday. “If someone wants to make a profit by building better solar panels and generating better battery storage, then I don’t have a problem with that.” 

Warren and Sanders do agree on the boons of renewable energy technologies. When pressed on a phaseout of nuclear, which provides baseload power, Warren pointed to energy storage as a possible solution. Sanders also noted an “explosion of technology” as cause for hope in confronting climate change.

“The truth is it costs a lot more to build a new nuclear plant today than it does to build solar or wind,” said Sanders at the town hall. “I think it is safer and more cost-effective to move toward sustainable technologies like wind, solar and geothermal.” 

Biden also noted that he plans to double the rate at which the U.S. is currently installing solar and wind. In 2018, according to Wood Mackenzie Power & Renewables, the U.S. installed about 10.7 gigawatts of solar, a decline of 2 percent from additions in the previous year. The wind industry is slated to install 11.9 gigawatts in 2019 and 14.6 gigawatts in 2020.

Several candidates, including Biden, Warren, Harris and South Bend, Indiana Mayor Pete Buttigieg, also floated plans for drastically increasing electric vehicles and charging infrastructure.

The Green New Deal — which many candidates credited for the very existence of a televised climate-focused town hall — also featured prominently, with candidates promising millions of good-paying jobs and support for marginalized communities that have faced disproportionate impacts from pollution and climate change.

As the primary progresses, expect that framing to continue playing a central role. Most candidates have incorporated elements of environmental justice within their plans, including, most notably, Harris, Castro and Booker. On Wednesday, Warren said her plan in that area is “not all the way stretched out yet” but is on the way.