A hybrid bus that runs on hydrogen and electricity opened its doors to the public on December 29 in Thousand Palms, Calif., according to a report in the Riverside Press-Enterprise. The vehicle, operated by the SunLine Transit Agency, is the first of its kind to be used in a public fleet in the United States.The hydrogen fuel for the 40-foot-long bus is created from wind power and solar power. The bus cost about $600,000 to build and is part of a million-dollar U.S.-Canadian initiative aimed at bringing cleaner-fuel technologies to public roadways. SunLine is one of the first public transit agencies in the nation to convert its entire fleet from traditional diesel to alternative fuels, according to the report.The fuel, generated at SunLine's headquarters, is created using wind power and solar power. The hybrid bus will refuel at a local facility. Hydrogen tanks are stored in the vehicle's roof. The bus does not use fuel cells, which utilize hydrogen mixed with oxygen to produce the electricity that propels a vehicle. As with hybrid vehicles sold to consumers, the bus is powered by an internal-combustion engine and an electric motor. To further boost its efficiency, the bus also recovers some of its energy from regenerative braking, which captures kinetic energy otherwise lost as heat in the brakes.If SunLine chose to mass-produce the hybrid bus, the price would come down to about $350,000. That is the average cost of one of the agency's natural-gas vehicles, according to the report.