Hydrogen (H2) will play an important role in developing sustainable transportation in the United States, because in the future it may be produced in virtually unlimited quantities using renewable resources. Hydrogen has been used effectively in a number of internal combustion engine vehicles as pure hydrogen mixed with natural gas.
There are currently no commercially available hydrogen vehicles. However, various tests are being run by the U.S. Department of Energy's Advanced Vehicle Testing Activity to gauge the feasibility of using hydrogen in internal combustion engines. A recent activity tested the safety and operation of a Mercedes Sprinter Van running on pure hydrogen as part of the Arizona Public Service fleet. For information on this vehicle and other hydrogen vehicle testing, see the DOE Advanced Vehicle Testing Activity site. In addition, vehicles can run on hydrogen/compressed natural gas (HCNG) blends. Currently, tests are being run by DOE on transit buses that can fuel with HCNG blended at a ratio of 20% hydrogen to 80% compressed natural gas.