Current "low tech" solution for storing hydrogen is to compress it to 5000 psi (340 atmospheres) inside a special superstrong carbon-composite tank. This technology is being developed by Fuelmaker Corporation:
Fuelmaker Corporation
The 5000 psi pressure vessel would need a capacity of about 5 liters (1.32 gallons) to store the compressed hydrogen, which would normally occupy 1.712 cubic meters at standard temperature and pressure. This amount of hydrogen would only be good enough for 50 km (30 mile) range, and simply represents my estimate of a typical daily round-trip commute to work. A 6.6-gallon tank would be good enough for a whole week of commuting. Hydrogen doesn't weigh much, it just takes up a lot of volume compared to liquid petroleum. A 6.6-gallon tank isn't that big though - about as big as a typical motorboat gas tank. Ever gone fishing in an 18-foot aluminum boat and a 25-hp outboard motor? Then you've seen a tank of comparable size.
Off Topic » in reply to You're at it again, SM
Re: You've totally misunderstood my numbers