The U.S. power sector is halfway to zero carbon emissions, according to a Lawrence Berkeley National Laboratory, or Berkeley Lab, report published earlier this month.

The report, which was prepared for the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy, found that carbon dioxide emissions from the U.S. power supply were 1,450 million metric tons in 2020 — roughly 50% below the U.S. Energy Information Administration’s 2005 Annual Energy Outlook’s estimate of 3,008 million metric tons.

Ryan Wiser, the lead author of the report and department head at Berkeley Lab, said the findings indicate a “tremendous accomplishment,” that is rapidly bending the carbon curve over a 15-year period.

“The goal of reducing carbon emissions is entirely about trying to manage, mitigate and reduce the degree to which the climate changes as a consequence of human-induced emissions,” Wiser said.

Wiser and his colleagues accredited the emissions reductions to several policy, market and technology drivers, with the replacement of coal with natural gas playing a “crucial role.”

Other key drivers of emissions reductions included the outperformance of wind and solar in 2020, which delivered 13 times more generation than previously estimated, the report found.

“No one would argue that we’ve had a coherent and consistent and stable federal or series of state policies leading us toward decarbonization,” Wiser said. “Despite that, we’ve managed to make pretty strong progress.”

Wiser said the wider impacts of the transition toward a carbon-free power sector include a reduction in air pollutants that cause respiratory disease, premature illness and even death, as well as an increase in power-supply jobs. He also noted that carbon emissions have decreased without dramatic increases in electricity bills — a “win-win scenario.”

While natural gas has played a significant role in reducing carbon emissions thus far, to reach net-zero emissions, gas would no longer continue to be part of the solution set, Wiser said.

“The path ahead is going to look different than the past, up to this point,” Wiser said. “The good news is that that pathway, at least in the near term, seems pretty clear.”

Wind, solar and storage technologies will continue to be key elements of the push toward additional power sector decarbonization, Wiser said. 

However, looking further down the road, Wiser sees a need to move beyond the power sector and tackle other carbon emissions sources through electrification.