A fleet of electric buses have arrived in downtown Dallas.

The seven new buses started running July 2 on DART's free downtown service, the D-Link route. DART unveiled them to stakeholders and media at an event Tuesday.

The quieter, zero-emission buses charge at the Dallas Convention Center station after each 19-mile service loop. The buses pull into the station, where batteries on the tops and bottoms of the buses fully recharge in less than 10 minutes.

The buses, built by the company Proterra, are more expensive upfront than other buses in DART's fleet. Each electric bus costs $971,000, compared with $480,000 for a bus that runs on compressed natural gas.

But over the lifespan of each electric bus — about 12 years — DART can expect to save between $300,000 and $400,000 on fuel.

If the electric buses are a success, DART would consider expanding the program, spokesman Mark Ball said in January, ahead of the launch.

"It just so happened that we did have the D-Link available to us, which seemed to fit the requirements to this type of bus operation perfectly," Ball said at the time. "The fact that it is a green opportunity makes us happy as well."

The electric buses were scheduled to roll out in 2016, but delays pushed that date back to March, then to July.

DART will bring buses on-site at two events later this month to show them off to the public. One will be at 11 a.m. July 25 at the Pegasus Plaza, located at 1500 Main St. The next will be 10 a.m. July 28 at the Dallas Farmers Market.