Storing Hydrogen

Another possibility is storage of hydrogen in carbon nanotubes. The walls of these tubes consist of a single layer of carbon atoms arranged in hexagonal patterns. The nanotubes can condense and safely store high volumes of hydrogen in a small space. Then the stored hydrogen can be released on demand by small changes in temperature and pressure.

Some nanotubes can store up to 67 kilograms of hydrogen per cubic meter (kg/m³). At that rate, it would take about 0.075 cubic meters (19.5 gallons) to store 5 kilograms of hydrogen. That’s about the size of some cars’ gas tanks, to store about 605,000 BTU—the energy in 5.3 gallons of gasoline.