Building a 100% renewable energy power grid in the United States by 2030 or 2040 would require an investment of $4.5 trillion in new wind and solar power, transmission lines and storage, an analysis by researchers for the Wood Mackenzie firm concludes.
That price tag would cost U.S. households nearly $2,000 per year through 2040, according to the study.
“The scale of the challenge is unprecedented, requiring an upending of fossil fuel industries and a complete redesign of the power sector,” the study’s authors said. No large, complex electric power system in the world operates with average annual wind and solar supply greater than 30% of the total, it added.
But setting a zero-carbon generation goal at 80%, allowing natural gas to cover the remainder, and keeping current nuclear generation going would sharply lower transition costs, Wood Mackenzie said. Moving that end goal to a 2040 to 2050 range would allow room for new clean energy technologies to be developed and reach commercial scale, they added.
Wade Schauer, Wood Mackenzie director of Americas power research, said, “In areas of the country that have a decent mix of wind and solar potential, those places can probably get to 50% renewables without struggling.” Above 50%, the challenge of ensuring reliable grid operations starts to take off, he added.
The $4.5 trillion estimate is in line with a proposal by Democratic presidential candidate and former Rep. Beto O’Rourke of Texas to hit a zero carbon generation target by 2050 at a cost of $5 trillion.
It also tracks a projection from the opposite political pole, an analysis by the conservative American Action Forum that found moving the U.S. grid to net zero greenhouse gas emissions in 10 years would require $5.4 trillion in new wind and solar generation and other infrastructure (Greenwire, Feb. 25).
Former Vice President Joe Biden’s climate plan calls for $1.7 trillion in federal spending on clean energy infrastructure in 10 years that would spur additional state, local and private sector investment to reach a total above $5 trillion (Climatewire, June 4).
Should nuclear count?
The clean energy proposals could cleave a huge policy gap between President Trump and his Democratic opponent.
But Democratic candidates and supporters are themselves split over whether the goal should be defined as renewable power, which would not leave a place for nuclear power, or zero carbon emissions, which would. More than 600 progressive political groups, including the Sunrise Movement and Friends of the Earth, have called on Congress to rule out nuclear power, biomass resources and carbon capture from a Green New Deal plan.
Biden seeks zero net emissions no later than 2050 and would include new nuclear reactor technology as a research priority.
Nuclear power also figures in a clean energy strategy proposed by a consulting firm headed by Obama Energy Secretary Ernest Moniz and the IHS Markit Ltd. consulting group led by energy historian and analyst Daniel Yergin. It was prepared this year for the Breakthrough Energy Coalition, a group of private investors headed by Microsoft Corp. co-founder Bill Gates.
“The idea that we’re going to have by 2050 … a 100% renewable system is not realistic, straightforwardly, certainly not at a reasonable cost,” Moniz said in an interview. “It doesn’t violate the laws of physics to do it. But that doesn’t mean it is politically or economically implementable, and I think that is the issue” (Energywire, Feb. 6).
The critical factor in very high levels of renewables with no nuclear power contributions is the future capacity of utility-scale battery storage, Schauer said.
His firm estimated that 1,600 gigawatts of new wind and solar generation capacity would have to be installed to replace all U.S. fossil fuel generation.
Today, the U.S. power grid has about 1,060 GW of power generation capacity that includes about 130 GW of wind and solar, Wood Mackenzie said. Getting to 100% renewables by 2030 would require adding more wind and solar installations in the next 11 years than the total capacity from these two sources installed in the past 20 years, it said.
In a 100% renewables plan, that much new wind and solar would require 900 GW of battery storage backup in the United States alone.
“Worldwide, there are only 5.5 gigawatts of battery storage in operation or under construction,” Wood Mackenzie said.
Under the analysis, the costs of new wind and solar units needed in the United States to meet a 100% renewables national standard would be roughly $1.5 trillion. Adding the required battery storage would raise the cost to $4 trillion. New power lines would increase the total to $4.5 trillion, the study concluded.
An 80% target, with gas generation as backup, would cut new battery storage costs by 60%, Wood Mackenzie said. But it would keep adding carbon emissions to the atmosphere unless and until carbon capture for gas units was practical and affordable.
‘It’s going to get harder and harder’
Utilities’ enthusiasm for the battery option is growing as costs of utility-scale batteries fall. Several large utilities have announced investments in combined solar generation and battery backup to replace coal-fired power plants.
Wood Mackenzie notes that with their four- to six-hour capacity, current utility batteries are well suited to fill in, kilowatt for kilowatt, when wind and solar production temporarily dip, or extend renewable power’s daily output across more hours of the day.
One example is in New York. The state’s new climate legislation would mandate that renewable power provide 70% of the state’s electricity supply by 2030, with full removal of carbon dioxide emissions by 2040. Nine GW of offshore wind and 6 GW of distributed solar would be backed up by 3 GW of energy storage, with all the new resources in place by 2035 (Energywire, June 21).
A subsidiary of Anbaric Development Partners is seeking to build an undersea transmission network off New York’s Atlantic coast to bring 2.4 GW of that offshore wind power inland. Battery backup is particularly valuable at that location, says Luis Ortiz, Anbaric’s vice president for microgrids.
In New York, the two geographic areas where storage is most helpful are New York City and Long Island, Ortiz said. Both have very limited transmission line access to the rest of the state and other regions. And storage will replace older fossil fuel “peaker” generators whose emissions pose health threats to nearby urban neighborhoods, he said.
Tapping batteries for four to six hours is very similar to the way the gas peaker units are often used, he added. “You have a technology that is getting cost competitive at a time when the state would like to see those [peaker] resources gone for general emissions purposes” and for environmental justice reasons, to protect threatened communities, he said.
But much larger battery installations are required to overcome dayslong droughts in wind speeds or sunshine. If wind or solar replaced a 2 GW nuclear power plant, and batteries provided the sole backup, 6 to 8 GW of battery storage would be required, Schauer said.
“It’s going to get harder and harder the closer you get to 100%. The question is, is going from 80% to 100% really going to save the planet, or should you put your effort into something else, such as focusing on energy systems to decarbonize the transport system, and waiting for technology to deliver the last 20% rather than rushing to get there really quickly and paying a lot of money for that?” Schauer said.