More electric vehicles are coming. But can cities power them?

The gas and electric company in Spokane, Wash., is giving away electric car charging stations, at least temporarily, and cities across the country are watching to see how it goes.

Spokane, a town of 200,000 in the eastern hills near the Idaho border, has a burgeoning market of electric vehicle drivers. And Avista, the utility company, wants to develop that market. So Avista has started a pilot to put in more than 270 charging stations in homes, offices and public locations. It’s costing the company about $3 million, just a fraction of its $1 billion annual revenues.

Cities across the country are playing with their use of electricity, hoping to manage consumer interest and improve municipal electricity use at the same time — the so-called “smart grid” approach. As consumers and companies continue to draw more energy, cities are testing ways to use less when they can — “flash charging” electric buses, or dimming street lights in early morning hours, for instance.

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All of these ideas have consequences for the power grid. A key question for Avista: When will Spokane residents plug in their cars?

The company needs to be able to adjust for consumer use if electric cars take off. Too many cars charging at once could drain Spokane’s power. If, some day, 500,000 cars all plug in one afternoon, they’d gobble up about 10,000 megawatts, figures Bryan Cox, the utility’s director of transmission and distribution operations. That’s five times Avista’s current feed.

But if those cars plugged in at various times over the whole day — and, importantly, outside of peak hours — they’d use more like 240 megawatts at once, not even one-quarter of the utility’s current load.

The company is putting in the stations, all loaners, now. They’ve had plenty of interest.

“We need to better understand charging behavior,” Cox said. “And how we can shape behavior to fit in with the grid.”