1. What is hydrogen, anyway?
Hydrogen is the first element in the Periodic Table. It is rarely found in elemental form, but is rather combined with another hydrogen atom to make the compound H2. While very small amounts of H2 are present in the atmosphere, this molecule is usually bound to 1 oxygen atom to make H2O or dihydrogen monoxide, more commonly known as water.

The bond between hydrogen and oxygen is very strong, requiring a lot of energy to separate them. However, hydrogen and oxygen give off a lot of energy when they are united, either by combustion or in a fuel cell.

Scientists have always admired hydrogen for its simplicity and its energetic nature. Unfortunately, these properties make hydrogen in its gaseous form difficult to store and transport. One kilogram of hydrogen (equivalent to a gallon of gasoline or diesel) occupies 431 cubic feet of space…about the volume of a small office cubicle.

To store and transport hydrogen efficiently, it must be compressed or turned into a liquid. Compression to 350 to 700 times atmospheric pressure (5,000 to 10,000 pounds per square inch) is common for automotive applications. Compression requires a lot of energy, and the storage tanks to safely contain these pressures are heavy and expensive.

Liquefying hydrogen takes even more energy, since hydrogen does not turn into a liquid until it reaches a temperature that is only 17 degrees above the temperature of interstellar space. Hydrogen liquefies at 20ºA (above absolute zero) and interstellar space is 3ºA. Storing liquid hydrogen requires a very high technology Thermos bottle called a Dewar Flask to prevent the hydrogen from turning back into a gas.

Both storage techniques are expensive. The base cost of hydrogen is multiplied by factors of 3 or 4 to purchase these expensive bottles and delivery vehicles required by the high pressures and low temperatures.