Electric-car sales are not charging the marketplace. A new study by online automotive research company Edmunds.com suggests the segment may have run out of gas.

Sales of electric drive vehicles are stuck at about 3.6 percent of all new-car sales for 2014, Edmunds senior analyst Jessica Caldwell said.

That’s below the 3.7 percent market share for 2013, and it’s not likely to grow any before the end of the year.

And that’s during an otherwise robust sales season. Total figures for August were higher than at any time in the last decade.

Automakers sold about 1.6 million vehicles in the U.S. in August, an increase of about 3 percent from August 2013, according to initial industry estimates released Wednesday.

“The whole automobile market has grown,” Caldwell said. “We’re not seeing electric vehicles as part of that growth.”

The numbers are surprising, Caldwell said, to automobile forecasters. Five years ago, analysts thought that electric-vehicle sales would continue to expand as more manufacturers put more electric vehicles on the road and as the vehicles’ cost came down.

That hasn’t happened. Electric-vehicle sales have slowed while prices have come down and dealers have been offering increasingly better deals on financing and incentives.

“It isn’t growing,” Caldwell said. “It’s stagnant and even slightly down.”

Caldwell said stable gas prices and increasingly good fuel efficiency are responsible.

Buyers are looking at the higher average price of electric vehicles, Caldwell said, and deciding that “the math doesn’t really work out.”

Could strong sales in the fourth quarter reverse the trend?

Not likely, Caldwell said.

“The latter part of the year, as the weather gets colder, there tends to be more SUV and truck sales,” Caldwell said. “So I don’t expect to see a run on electric vehicles.”

Tesla Motors has chosen Nevada as the site for its proposed $5 billion “gigafactory” battery plant.

The state’s governor, Brian Sandoval, will announce the deal Thursday afternoon at a news conference in Nevada’s capital, Carson City.

Confirming the details, first reported by CNBC, a Tesla representative said: “We are in ongoing discussions … and look forward to joining the governor and members of the Legislature tomorrow.”

In winning the contract, Nevada beat out California, Texas, Arizona and New Mexico to become the new home of the factory where Tesla, in partnership with Japanese electronics giant Panasonic, will build the lithium ion power plants for its Model S and Model X electric vehicles.