Opinion: Why electric cars are good for the grid

Many are claiming that the U.S. electrical grid is not prepared for electric vehicles. In a hearing held July 19, 2022, Kentucky Rep. Thomas Massie compared a refrigerator’s power consumption to an electric car’s power consumption. Purportedly based on a U.S. Department of Energy report, he claimed that an electric car consumes 25 times as much power as a refrigerator. Based on my experience as an electrical engineer, the values sounded wrong, and I did some research of my own.

I looked at the specs of five refrigerators ranging from 7.5 cubic feet to 20.5 cubic feet and of different brands, models and styles. The estimated annual energy usage ranged from 365 kilowatt-hours to 540 kilowatt-hours, with an average of 413.2 kilowatt-hours. The average number of miles driven per vehicle per year in the US is about 14,000. A long-range all-wheel drive Tesla Model Y gets about four miles per kilowatt-hour. It is a midsize SUV and is typical of the average vehicle driven in the U.S. It would use about 3,500 kilowatt-hours in a year for the average driver, or about 8.5 times the energy consumption of the typical refrigerator. That said, comparison to refrigerators is of little significance.

Electricity use in the United States grew from 1,747 terawatt-hours in 1975 to 2,324 terawatt-hours in 1985, a 33% increase. Consumption has been nearly constant from 2005 to 2023. In 2023, the total electrical energy consumption in the U.S. was 4,000 terawatt-hours. There were 283.4 million registered vehicles in the U.S. in 2023. There are reportedly 3.3 million registered electric vehicles in the U.S. Assuming a constant number of vehicles and miles driven per vehicle, the increase in electrical energy consumption with 283.4 million electric vehicles would be 980 terawatt-hours, or 24.5%.

Rep. Massie’s concern was a mandate to ban the sale of non-zero-emission vehicles in 2030. Gas and diesel-powered cars would not disappear instantly in 2030. Most of the petroleum-fueled cars will be around for another five years. Based on past performance, the U.S. should easily be able to meet the needed rate of growth in electricity production.

The electric utilities have to build and maintain power lines, transformers, switching equipment and generation facilities to meet the peak load. The biggest challenge to the grid is air conditioning, whose usage is highest in summer months in the afternoon and early evening. Particularly hot days can result in brownouts. Most EV owners who charge at home do so late at night during the time of lowest power usage. During long trips, Level 4 chargers are typically used. The dominant Level 4 chargers in the U.S. are Tesla Supercharges. They use only renewable energy. Most new Tesla Supercharger stations have a large battery so that they can buy power during low usage times and draw from the battery during peak consumption periods.

It is an economic benefit to utility companies to have a more constant consumption of electrical power. EVs help them to be more profitable and make better use of their equipment. EVs will help finance the construction of more nuclear, geothermal, solar and wind power. If something is stressing the grid, it is ACs, not EVs.

In China, over half of the new cars sold are EVs. In Norway, over 90% of new cars sold are EVs. If they can do it, why can’t we?

Lloyd G. Miller is a retired electrical engineer who lives in Utah. He earned his bachelor’s and master’s degrees in electrical engineering at BYU.