SEATTLE -- When Seattle City Light unveiled five new electric vehicle charging stations last month in an industrial neighborhood south of downtown, the electric utility wasn't just offering a new spot for drivers to fuel up. It also was creating a way for the utility to figure out how much more power it might need as electric vehicles catch on.
Seattle aims to have nearly a third of its residents driving electric vehicles by 2030. Washington state is No. 3 in the nation in per-capita adoption of plug-in cars, behind California and Hawaii. But as Washington and other states urge their residents to buy electric vehicles -- a crucial component of efforts to reduce carbon emissions -- they also need to make sure the electric grid can handle it.
The average electric vehicle requires 30 kilowatt-hours to travel 100 miles -- the same amount of electricity an average American home uses each day to run appliances, computers, lights and heating and air conditioning.
A U.S. Department of Energy study found that increased electrification across all sectors of the economy could boost national consumption by as much as 38% by 2050, in large part because of electric vehicles. The environmental benefit of electric cars depends on the electricity being generated by renewables.
So far, states predict they will be able to sufficiently boost power production. But whether electric vehicles will become an asset or a liability to the grid largely depends on when drivers charge their cars.
Electricity demand fluctuates throughout the day; demand is higher during daytime hours, peaking in the early evening. If many people buy electric vehicles and mostly try to charge right when they get home from work -- as many currently do -- the system could get overloaded or force utilities to deliver more electricity than they're currently capable of producing.
In California, for example, the worry is not so much with the state's overall power capacity, but rather with the ability to quickly ramp up production when demand is high, said Sandy Louey, media relations manager for the California Energy Commission, in an email. About 150,000 electric vehicles were sold in California in 2018 -- 8% of all state car sales.
The state projects that electric vehicles will consume 5.4% of the state's electricity, or 17,000 gigawatt-hours, by 2030.
Responding to the growth in electric vehicles will present unique challenges for each state. A team of researchers from the University of Texas at Austin estimated the amount of electricity that would be required if every car on the road transitioned to electric. Wyoming, for instance, would need to nudge up its electricity production only 17%, while Maine would have to produce 55% more.
Efficiency Maine, a state trust that oversees energy efficiency and greenhouse gas reduction programs, offers rebates for the purchase of electric vehicles, part of state efforts to incentivize growth.