Commuters, and maybe a few visiting delegates, will get a sneak preview of SEPTA's new electric buses during the Democratic National Convention next week.

An emissions-free bus will offer rides in Center City, shuttling passengers between stops near City Hall, the Pennsylvania Convention Center and Independence Mall.

"You know, we're deploying at the DNC, but this is by no means a blue state technology," joked Ryan Popple, CEO of Proterra, which manufactured the vehicle.

Earlier this year, SEPTA announced plans to add 25 electric buses to its fleet by next spring, supported by a $2.6 million grant from the Federal Transportation Administration. The money will cover the cost difference between a diesel-hybrid bus and the electric option.

Constructed from carbon fiber and other lightweight materials, Proterra's buses have a range of up to 50 miles, and can recharge in under 10 minutes. In Philadelphia, the electric fleet will initially serve Routes 29 and 79.

"This is the highest tech transit bus in the world," said Popple. "You don't have any of the smell or noise of diesel. It's a much more pleasant experience. The biggest thing you notice is you can talk to the passenger sitting next to you."

The 40-foot model can accommodate up to 77 passengers, and comes with a sticker price of $749,000. Proterra manufactures its batteries in California, and assembles the buses in South Carolina.

It's already delivered units to cities including Nashville, Louisville, Worcester, and Tallahassee, and has orders from more than a dozen more metropolitan areas.