Hydrogen is a storage technology, not really an energy source. Hydrogen competes with Li-ion batteries.
How many Li-ion batteries do you need to equal one 200-ton liquid H2 storage tank? At 120MJ per kg, 200-tons == 200,000 kg == 6GW-hrs of electricity. There's no Li-ion battery in the world that's anywhere close to that kind of storage capacity... and various researchers are aiming at 3000ton H2 storage tanks.
Erase 50% or even 80% of the energy due to inefficiency / costs of cryogenics, and you still have a bigger energy storage tank from H2 than anything possible with Li-ion. And the future of H2 is looking like 10x capacities are reasonable over the next 10 years.
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Whatever solar solution you were thinking, just do the same except instead of using big, expensive, heavy Li-ion batteries, replace the storage mechanism with H2 fuel cells.
Higher energy density = higher danger of releasing it unintentionally.
I totally understand why hydrogen is a great rocket fuel. You need this high energy content and the extreme lightness for high Isp.
On land, I suppose, the energy density of 100 tons of hydrogen in one place is unnecessarily high. The fact that hydrogen has no odor, and its flame is entirely infrared, invisible, does not help.
By the same token, I think that lithium batteries have excessive energy density for large-scale land applications, like buffer storage for solar / wind power. Even a lead-acid battery, with all its environmental downsides, weight, etc is at least not a major fire hazard. I suppose that large-scale electricity storage will take off when cheaper and safer, while less dense, alternatives to lithium batteries are commercialized.
As a power source for a car, a lithium battery at least is not cryogenic. OTOH on the scale of a train this may already be not a big problem. Same possibly for an oceangoing ship, but it would be terrible to start losing fuel and power if a bad storm damages the cryogenic system.
An ideal (fantastic) system could use methane and turn it into carbon, only oxidizing the hydrogen. Sadly, similar reactions only work so far with much more complex molecules.
Hydrogen is a storage technology, not really an energy source. Hydrogen competes with Li-ion batteries.
How many Li-ion batteries do you need to equal one 200-ton liquid H2 storage tank? At 120MJ per kg, 200-tons == 200,000 kg == 6GW-hrs of electricity. There's no Li-ion battery in the world that's anywhere close to that kind of storage capacity... and various researchers are aiming at 3000ton H2 storage tanks.
Erase 50% or even 80% of the energy due to inefficiency / costs of cryogenics, and you still have a bigger energy storage tank from H2 than anything possible with Li-ion. And the future of H2 is looking like 10x capacities are reasonable over the next 10 years.
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Whatever solar solution you were thinking, just do the same except instead of using big, expensive, heavy Li-ion batteries, replace the storage mechanism with H2 fuel cells.