Liquid hydrogen as energy storage

[feargach]

What are the technical problems with using intermittent wind power to create hydrogen.

The hydrogen is then cooled to a liquid, and stored for use at high-demand periods. Hydrogen burns cleanly with no carbon emission.

So if the wind blows hard on Monday, but the air is still on Tuesday and Wednesday, you still get power every day if you have enough turbines.

http://en.wikipedia.org/wiki/Liquid_hydrogen

[johnfás]

Maybe you just made yourself a million

That is until someone who did engineering turns up. All sounds very good to I who studied History and Politics at university :P

[Leftfemme22]

To keep Hydrogen liquid requires temperatures near absolute zero which requires more energy than can be drawn from the hydrogen in the first place. Making it non-feasible.

"In terms of energy density, liquid hydrogen requires much more volume than other fuels to store the same amount of energy."

[johnfás]

Maybe you just made yourself a million

That is until someone who did engineering turns up. All sounds very good to I who studied History and Politics at university :P

To keep Hydrogen liquid requires temperatures near absolute zero which requires more energy than can be drawn from the hydrogen in the first place. Make it non-feasible.

"In terms of energy density, liquid hydrogen requires much more volume than other fuels to store the same amount of energy."

Told ya!

Isn't that why the Hydrogen Fuel Cell car is a bit of a non runner at the moment because its so volatile - or am I on a different track here?

[feargach]

How much does it cost to keep something at such low temperatures?

Does it scale? Are economies of scale possible?

Does it cost 1000 × as much to keep a 1000 litre container at 20 Kelvin as a 1 litre container? Maybe it costs 5000 × as much, I wouldn't know.

I know supertankers cross the oceans with massive spherical containers holding gas at 100 Kelvin, which is cold enough to turn you into an ice cube immediately.

Like I said, I'm not saying I know it's feasible, I just want to know whether they're the kind of engineering obstacle that can be overcome or not.

[HanleyS]

Wouldn't hydrogen be liquid at a higher temperature if it was pressurised?

[Andréasft]

On a Myth busters episode, it was proven that some cars today can run off hydrogen gas, but it is not good to that since it can catch on fire or blow up.

I like solar energy, but it is not efficient enough. Current solar panels can only take in energy from one color.

[Simon.D]

From: http://www.kbr.be/~capas/Rapports/Hydrogen.pdf

Main advantages
- Uncoupling of primary energy sources and utilization.
- Hydrogen is a gas, thus easier to store than electricity.
- Hydrogen can be obtained from any primary energy source, including renewable.
- Decentralized production is possible. Hydrogen is viewed as capable of providing services where electricity is not available, in particular as a fuel for vehicles and energy storage in remote areas.
- Very efficient when used in fuel cells.
- Very good experience of hydrogen as a chemical reactant (ammonia, methanol, oil refining).
- Very good safety records (for a specific range of applications).

Drawbacks
- Poor overall energy efficiency when produced from electricity made with fossil fuels.
- Very low density and poor specific volume energy density.
- Need for high pressures and very low temperatures if stored in the liquid phase.
- Specific safety problems and poor public acceptance (Hindenburg syndrome, Apollo 16, Challenger space shuttle).
- No existing infrastructures for transport, distribution and storage.
- Rather high cost (up to now).

Personally I think hydrogen is the way of the future, and the only avenue by which wind energy can actually become a big player in the energy market, and probably our only hope on this island to make ourselves energy independent.

[Simon.D]

How much does it cost to keep something at such low temperatures?

According to that report I left a link for, it costs up to 30% of the overall energy to cool the Hydrogen down to 20K, and an expensive insulated tank to keep it there..

Does it scale? Are economies of scale possible?

Does it cost 1000 × as much to keep a 1000 litre container at 20 Kelvin as a 1 litre container? Maybe it costs 5000 × as much, I wouldn't know

I suppose the cost of the tank is the deciding factor on scale.. i.e. as the tank gets smaller the ratio of tank cost to fuel weight steadily increases.. It may not be economically feasible to power a car from liquid hydrogen..

But then there's compressed hydrogen gas which requires a much cheaper tank, just one that needs to be very strong to withstand pressures up to 200 bar.. However very strong = very heavy, unless the likes of carbon composites are being used.

So Very Strong Steel tanks could be used to store Hydrogen, relatively efficiently, beside the wind farm, and at other static locations.. i.e. power plants, "Hydrogen" stations (as in the replacement for petrol stations), but not in automotive vehicles as they're too heavy and energy costly to be moving about.

Carbon fiber hydrogen tanks work in theory for transport, being light enough and strong enough to store high pressure hydrogen, but the technology is still being developed.

[Auditor #9]

On Derek Davis yesterday he was talking with Seán Whelan(?) about European Ministers' uses of Green cars. Whelan referred to a 7Series BMW which runs on hydrogen used by some Commissioner! It has a range of over 600km and they were joking that between Brussels and Strasbourg which is just over 400km the car will not have a problem but coming back...

From Intercert(remember that?) physics/chemistry you learn that hydrogen is liberated from water once an electric current is passed through it, thus the combination of wind+hydrogen.