Adding to the debate around the pace of the transition to zero- or low-carbon energy, a new report from the University of California, Berkeley's Goldman School of Public Policy said it is feasible for the U.S. to transition to 90% carbon-free power by 2035.

In forecasting renewable energy prices, most everyone — in academia, the private sector and government — has gotten it wrong, according to the study, released June 9.

"All the experts have been wrong in the past of how fast solar, wind and storage prices have fallen," Nikit Abhyankar, a senior scientist at the school and a co-author of the study, said in an interview. "And that includes us as well."

The U.S. could reach the 90% target by retaining existing hydropower, nuclear and natural gas capacity, which would be used sparingly, and adding battery storage as well as 1,100 GW of new wind and solar generation. Consumers would not see increases in their energy bills as renewable energy prices continue to fall, according to the study.

The study took aim at the goal, recently proposed by Congressional Democrats, of transitioning the country to carbon-free power by 2050. Recent studies have indicated that 2050 is not a quick enough time frame. In 2018, for instance, the United Nations Intergovernmental Panel on Climate Change released a report that said the world must slash emissions in half by 2030 to avoid the most catastrophic effects of climate change.

Co-author David Wooley, a visiting professor at UC Berkeley's Goldman School of Public Policy and executive director of the Center for Environmental Public Policy, said a 2050 timeline is not aligned with the urgency of averting the worst effects of climate change, "and we wanted to see how far we can go for existing technology."

"When we looked at 2050, we began to think it's just too late from what the science is saying, and there's a risk of, if you set [that] goal for yourself that you're just kicking the can down the road," Wooley said.

"The policy debate has historically focused on 2050 because of a belief that transforming the global energy sector would be infeasible in the shorter-term," said David Johnson, an assistant professor of political science and industrial engineering at Purdue University who studies climate change policy. "2050 provided a long enough time lag for investments in R&D to pay off and for major fossil fuel exporters to reimagine their economies."

Some of those assumptions have since turned out to be false, Johnson said in an email. "Renewable energy costs have plummeted faster than expected, and cheap natural gas has made aging coal plants less competitive even under the current, long-entrenched subsidy environment."

Approaching zero

Another recent report, released by the Institute for Energy Economics and Financial Analysis, said, "Since we founded this global energy-finance think tank in 2013, IEEFA has consistently illustrated the ongoing deflationary trend in renewable energy, and more recently in battery costs. The ongoing rate of technology-driven cost declines has surprised all, even extreme optimists like us."

The IEEFA expects annual double-digit reductions in prices to continue over the coming decade, according to the report.

The IEEFA said it expects variable renewable energy generation costs to be "near zero" between 2030 and 2040 in certain high-quality resource areas. "Ongoing technology enhancements, combined with a manufacturing scale today that was undreamt of only a decade ago," have driven the cost of a solar module down to 17 cents to 20 cents per watt, down 90% from 2010. The report pointed to forecasts by the International Energy Agency, which the IEEFA said continues "to be surprised every year over the coming decade at the speed of ongoing technology-driven deflation and hence the rate of uptake of renewable energy, electric vehicles and battery storage, as it has been for the past decade, every year without fail."

The Berkeley study also highlighted the degree to which price forecasters have consistently understated how much wind, solar and battery storage costs would fall.

A 2012 study by the National Renewable Energy Laboratory, for instance, "projected retail electricity price increases of about 40%–70% above 2010 prices, for a system with 90% renewable electricity penetration in 2050," the Berkeley study said. "Renewable energy and battery costs have declined much faster than these older studies assumed, which is the main reason their cost results differ so much from ours."

Reaching 90% by 2035 will require strong government policies, the report found. Without such policies, the maximum level of zero-carbon power level that could be reached is 55%.