Buses have been on acid trips since the early 1990s. There have been several demonstration projects around the United States and British Columbia since 1993. Phosphoric-acid fuel cells are being developed and tested for use in city buses in many major cities. Oakland, California, Chicago, IL, Vancouver, BC, and Palm Springs, California are all involved in demonstration projects for city buses using hydrogen fuel cells.
Phosphoric-acid fuel cells are well suited for bus use because of the power the can produce and the efficiency they exhibit. These cells take a long time to warm up to operating temperature and therefore don’t respond well for use in private autos, but since buses are not turned off during their daily operation this is not a problem and their efficiency is in the range of 40%-50%. Another advantage for using these kind of engines in buses is that refueling is done in a central location. Diesel and hybrid buses on the road now use a central refueling station and these can accommodate the hydrogen storage they need for refueling the buses.
Besides buses, the nations tractor-trailer fleets can also use these types of engines because they will provide the power needed for the long hauls these vehicles make and they run almost continuously so the warm up needed for proper operation is not an issue. The problem for the long haul truckers is the availability of refueling them with hydrogen. One solution to that could be the integration of fuel reformers on board that take natural gas and remove the hydrogen which would then be the source fuel for the engine. Natural gas could be made available at truck stops for their refueling. Although when using natural gas we are still dependent on fossil fuel, this would offer an alternative until hydrogen refueling could be done directly. We know that fossil fuels will become much more expensive in the future but we need to start doing these kind of things now in preparation.
To make fuel cells viable in the future, whether they be phosphoric-acid or proton exchange membrane (PEM) that are being tested for private autos, we need to develop the infrastructure for hydrogen refueling. Besides making the hydrogen available, we need to find ways of producing it without using fossil fuels.
Hydrogen is all around us but it’s locked up in compounds that need to broken down. More research needs to be done for an efficient way to generate hydrogen. Some research is being done to use waste gas collected from landfills, which produce methane and reforming it with steam, instead of using natural gas. Another method for generating hydrogen is to use a green energy or renewable energy source for the electrolysis of water giving us hydrogen and oxygen both of which are needed for the PEM fuel cell.