Most people think of electric vehicles as a cleaner, quieter and smarter alternative to traditional gas-powered cars, but another kind of electric vehicle is quickly gaining speed in the United States – the electric bicycle.

Consulting group eCycleElectric estimates that the U.S. electric bicycle market doubled between 2012 and 2013, according to an article in The Atlantic today.

While this estimate may be on the high side, analysts agree that the electric bicycle market is growing by leaps and bounds. Commuting by bicycle has become increasingly popular and cities have started to install new infrastructure to make it easier for bike commuters to travel safely. From pathways and bike lanes, there are more options for cyclists today than ever before. But electric bicycles might have trouble finding their spot.

The Atlantic article details the turbulence cities are experiencing as they try to correctly classify this new hybrid, as well as regulate it for both pedestrian and rider safety.

In the meantime, electric bicycle manufacturers, many of which are American companies manufacturing their bikes entirely in the U.S., are seeing sales increase and working to come up with new and creative ways to gain market share.

Hi-Power Cycles, based in California, announced this week that it has incorporated 24 percent efficient solar cells into a lightweight waterproof foldable nylon solar charging system.  The company offers the solar charging systems in a range from 60-watt to 300-watt systems.  Employee Antonio Contreras uses the 300-watt system to charge his 52-watt electric bicycle, which takes about two hours.

Conteras’ experience with his electric bicycle explains the growing popularity of the new transportation option. He commutes 30 miles round-trip every day. He used to do it manually with simple pedal power. While it was a good workout, it left him sticky and smelly during the workday.

Hi-Power Cycles founder Chris Hunt said he sees a lot of potential for the new folding solar charging system since it's affordable and portable. At 17 pounds, the 300-watt system can fold up into a backpack. It complements the electric bikes well, allowing bike owners to charge up their cycles for free.  He was quick to note that it could also have other applications too, however.

“The possibilities are endless with these panels,” Hunt said.  “We are excited to continue seeking the most efficient and well designed solar cells in the world.”