A recent U.S. Department of Energy (DOE) report found that fuel economy of fuel-cell electric buses was 1.8 to two times higher than conventional diesel buses (4 mpg) and compressed natural gas buses (3 mpg), a significant improvement toward the DOE and Federal Transit Administration’s (FTA) target of 8 mpg (diesel equivalent).
The 12-month status report, “Fuel Cell Buses in U.S. Transit Fleets: Current Status 2012,” written by the National Renewable Energy Laboratory (NREL), includes data collected from 18 fuel-cell electric buses at three transit agencies in California and Connecticut. In one year, the fleet of fuel-cell electric buses in the study traveled 250,000 miles and had almost 25,000 hours of fuel-cell system operation. The report also documented one fuel-cell system operating more than 12,000 hours, an advancement toward the DOE and FTA's 2016 target of 18,000 hours and the ultimate target of 25,000 hours.
The data and subsequent report is part of the FTA’s National Fuel Cell Bus Program; a cooperative initiative between government and industry to advance the commercialization of fuel-cell technology in U.S. transit buses. The program has awarded approximately $60 million for competitively selected projects, while industry has provided more than $60 million in additional private commitments. Under the program, the typical lifecycle of a project develops concepts, constructs prototypes, demonstrates and evaluates, and publishes findings.
Currently, there are several projects under way throughout the nation in the demonstration and evaluation process, including Oakland, Calif.-based AC Transit; Austin, Texas’ Capital Metro; and the Greater Cleveland Regional Transit Authority (RTA). So, how does this technology work, and more importantly, how are the buses responding in real-world applications? METRO Magazine spoke to these agencies as well as power system manufacturer, ClearEdge Power (formerly UTC Power), to find out.
In 2005, ClearEdge launched its PureMotion zero-emission proton exchange membrane (PEM) hydrogen fuel-cell system and has continually improved the technology to make the current fuel cells more durable and reliable.
“The current PureMotion system is more than three times more durable and powered a transit bus for more than 12,000 operating hours, while still producing full power,” says Dana Kaplinski, manager, transportation business for ClearEdge Power.
Fuel cells operate electrochemically and are combustion-free, as well as one of the cleanest energy-generation sources available in the world today, according to Kaplinski. A fuel cell running on pure hydrogen — like the PureMotion system utilized in transit buses — emits zero emissions at the source.
“PureMotion systems are now operating in fleets in California, Connecticut, Michigan and Ohio and have traveled more than 600,000 miles to date,” she says.
Ideally sized for transit vehicles, the PureMotion Model 120 power system generates up to 120 kW of net power. The modular design is intended to maximize uptime and simplify routine maintenance. The power system is particularly well-suited for integration into hybrid vehicle applications, according to ClearEdge.
In 2005, Thousand Palms, Calif.-based SunLine Transit was the first system to put a bus equipped with the PureMotion120 system in service. Hartford-based Connecticut Transit added its first hydrogen fuel-cell vehicle — a 40-foot Van Hool equipped with a UTC Power hydrogen fuel-cell — in 2007. Since then, the agency has added five more hydrogen buses.