Propane Tank

• 1000 gallon propane tank - used at $1000, weighs 1700 lb empty.
• New $2700 - [1]. New $3000 [2]
• Tank empty weights - [3]. 870 lb for 500 gal.
• 500 gal is 1.9 cu m.
• 1 cu m of hydrogen is 82 grams, so we have almost 160 grams stored in a 500 gal tank.
• Normal propane tank pressure is up to 200 psi - [4]
• 200 psi is 13.6 atm
• A 500 gal propane tank can store 1.1 kg of hydrogen. Thiis is 1.1 gallon gasoline equivalent.
• If we have 290 grams generated/day for $3500 of off-the-shelf electrolyzer as at Hydrogen Compression - then we need only 2 bar pressure in the 500 gallon tank. This pressure comes readily from the electrolyzer, so no pumping is needed.
• For one gallon gas equivalent - we need 6-7 bar of pressure in a 500 gal tank.
• Thus, here we see how a single propane tank suffices for hydrogen storage of 3kWhr equivalent using a Honda EU1000 generator - at 6-7 bar. And 6kWhr at its full pressure rating! And about 1.5 kWhr equivalent at 2 bar.