The Hydrogen Economy

Although the Internal Combustion Engine (ICE) in your car can burn hydrogen, the hope is that someday fuel cells, which are based on electrochemical processes rather than combustion (which converts heat to mechanical work), will become more efficient and less polluting than ICEs.¹ Fuel cells were invented before combustion engines in 1839 by William Grove. But the ICE won the race by using abundant and inexpensive gasoline, which is easy to transport and pour, and very high in energy content.²

... Here is how a hydrogen tank stacks up against a gas tank in a Honda Accord:

	Amount of fuel	Tank weight with fuel	Driving range	Tank cost
Hydrogen	55 kg @3000 psi	400 kg	165 miles13	$200021
Gasoline	17 gallons	73 kg	493 miles	$100

According to the National Highway Safety Traffic Administration (NHTSA), “Vehicle weight reduction is probably the most powerful technique for improving fuel economy. Each 10 percent reduction in weight improves the fuel economy of a new vehicle design by approximately eight percent.”

The more you compress hydrogen, the smaller the tank can be. But as you increase the pressure, you also have to increase the thickness of the steel wall, and hence the weight of the tank. Cost increases with pressure. At 2000 psi, it is $400 per kg. At 8000 psi, it is $2100 per kg.²⁰ And the tank will be huge — at 5000 psi, the tank could take up ten times the volume of a gasoline tank containing the same energy content. -skeptic