The electricity sector is responsible for one-quarter of greenhouse gas emissions in the United States, with roughly 60 percent of electricity still generated by burning fossil fuels, mostly natural gas and coal. The Biden administration sees curbing electricity emissions as central to its climate plans, since it is also trying to convince Americans to buy more electric cars and heat pumps that will plug into the grid.
But cleaning up the power sector will require more than just new laws, experts said. It also poses major technological challenges.
Several recent studies have found that utilities could plausibly get to 80 percent clean electricity using today’s technology, mainly by installing vastly more wind turbines and solar panels and relying on existing hydropower dams and nuclear reactors.
But cleaning up that last 20 percent of emissions could prove trickier. One obstacle: wind and solar farms only generate power when weather conditions are favorable. That means utilities today still rely on gas- or coal-burning plants for backup.
Many utilities are now installing large arrays of lithium-ion batteries, similar to those used in electric cars, to help smooth over fluctuations in supply. But those batteries typically store electricity for just four to six hours at a time, which is insufficient to handle larger seasonal swings in wind and solar power. Some regions of the country can go days or weeks with little wind.
There are plausible solutions, but many still have drawbacks. Grid operators could build massive new transmission lines across the country, on the theory that it’s usually windy somewhere. But some communities have opposed new power lines.
Utilities might also use surplus wind and solar power to produce hydrogen, which can then be burned cleanly for electricity during times of need. This fall, the New York Power Authority will test this kind of “green” hydrogen as a replacement for some of the gas it typically burns at a facility on Long Island. But, for now, this remains pricier than burning fossil fuels like natural gas.