Hydrogen Economy (cont)

In a hydrogen economy, hydrogen fuel would be manufactured from some primary energy source and used as a replacement for hydrocarbon-based fuels for transport. The hydrogen would be utilized either by direct combustion in internal combustion engines or as fuel in proton exchange membrane fuel cells. The primary energy source can then become a stationary plant which can use renewable, nuclear or coal-fired energy sources, easing the pressure on finite liquid and gas hydrocarbon resources. There is no carbon dioxide emission at the point of use. With suitable primary energy sources, greenhouse gas emissions can be reduced or eliminated. Excepting minor NOx generation from hydrogen internal combustion engines, the emission footprint of a hydrogen economy remains that of the underlying energy generation technology.

Hydrogen has a high energy density by weight. The fuel cell is also more efficient than an internal combustion engine. The internal combustion engine is said to be 20-30% efficient, while the fuel cell is 35-45% efficient (some even higher) (not accounting for losses in the actual production of hydrogen, which would result in an overall efficiency of about 25%) and together with the electric motor and controller, the drive train overall efficiency approaches 24% with low idling losses.

Perspective - Current Hydrogen Market

Hydrogen production is a large and growing industry. Globally, some 50 million metric tons of hydrogen, equal to about 170 million tons of oil equivalent, were produced in 2004. The growth rate is around 10% per year. Within the United States, 2004 production was about 11 million metric tons (MMT), an average power flow of 48 gigawatts. (For comparison, the average electric production in 2003 was some 442 gigawatts.) As of 2005, the economic value of all hydrogen produced worldwide is about $135 billion per year.