Ask HN: Why isn‘t „solar hydrogen“ a thing for seasonal energy storage? | Hacker News Reader

Ask HN: Why isn‘t „solar hydrogen“ a thing for seasonal energy storage?

4 pointsleobg13 comments

I don't know what percentage of global energy consumption can be attributed to heating homes and businesses. But it must be a substantive amount.

In Germany, most heating in winter is done by burning fossil fuels or wood.

For free-standing, single family homes, at least, I would assume that the amount of rooftop solar energy that can be captured using solar panels in summer would be able to provide much of the heating that's required in winter.

The true bottleneck seems to be storage.

Batteries don't work well for this:

The energy required for a year's worth of heating one home apparently is in the ballpark of 35,000ish kWh. To store that amount of energy in, say, Tesla batteries (which are said to have an energy density of about 260 kWh/kg), you'd be looking at 135 tons of batteries - costing around $8.5M.

Even with battery prices dropping, it won't be a viable option any time soon. (Besides, production of electric vehicles is already battery constrained.)

So, why not hydrogen?

Making hydrogen from the electric power provided by solar panels is easy. The stuff is flammable, and needs to be compressed - so that part does require some engineering to make it safe.

But then, you can store the stuff for pretty much as long as you like. Also, to transform the energy back into heat again, you burn it. This means that the basic principle of heating remains the same. The burner unit that used to burn oil or gas just needs to be converted to burn hydrogen. Or, if that doesn't work, you swap the burner unit. But the rest of the heating system can be left untouched.

It seems to me that such a system would offer home owners a way to become independent from utilities, energy politics and oil prices.

So, why isn't this a big thing already?

What other technology, if any, could be better suited to store solar energy in summer to use for heating in winter?

Thanks.

1. Hydrogen embrittlement - hydrogen makes metals containers brittle. Hydrogen storage has durability problems. Hydrogen penetrates metals and eventually leaks out.

2. weight&volume requirements of hydrogen storage systems are very high

3. Overall cost of hydrogen storage. Valves, pipes, inspections, security of handling, life cycle,...

search: >'Hydrogen storage in C60 (buckyball) lined container< @DDG : <https://html.duckduckgo.com/html/?q='Hydrogen storage in C60...>

Hydrogen Storage : https://en.wikipedia.org/wiki/Hydrogen_storage

Buckminsterfullerene : https://en.wikipedia.org/wiki/Buckminsterfullerene

Fullerene : https://en.wikipedia.org/wiki/Fullerene

Add:

search: >scholar:'Hydrogen Storage'< @DDG : <https://html.duckduckgo.com/html/?q=scholar:'Hydrogen Storag...>

Edit: fix url

Yes. Very expensive as I said.

1. Storage and pipes: highly regulated, you need local permits to store and use, and those are usually capacity-limited. And after that - the pipeline and various gas leak protection mechanisms are expensive.

2. Electrolyzer efficiencies are ~50%. (one way). Some new companies claim higher numbers, but it’s still 2-5 years away.

3. First viable use cases are micro-grids (towers, neighborhood, hospital, ..), rather than single homes

The cost and size of hydrogen storage would very likely preclude its use except if its out-of-town and then the great cost of piping it around would negate that usefulness.

Huge solid (stone, concrete) insulated heat-banks electrically heated by solar-power might be usable. But they'd pretty much have to be stored underground. The cost of doing so would be enormous. And it would very likely be impossible to retrofit existing buildings.

That is utterly wrong. Hydrogen storage and piping would be vastly cheaper than thermal storage in huge heat banks. In particular, you would store the hydrogen underground. Very few proposals are suggesting otherwise. Piping hydrogen would be no different than piping natural gas, and retrofits are fully possible. There's no way of transferring heat stored in big rocks at all, as far as I know.

Piping hydrogen would be no different than piping natural gas,

On the face of it, that would appear to be true. But far larger amounts of Hydrogen would be required to produce the same amount of energy than the equivalent amount of natural gas.

"But because hydrogen is so much lighter, or less dense, you need approximately 3 times the volume of hydrogen as compared to natural gas to get the same amount of energy." - https://www.powereng.com/library/6-things-to-remember-about-...

Generally, to transport and store Hydrogen, it is liquefied. That introduces a whole new set of problems, as you have to use metals that continue to be strong at very low temperatures for pipes and tanks.

https://www.energy.gov/eere/fuelcells/hydrogen-storage-chall...

If you are just talking about hydrogen piping, the velocity of hydrogen flow is faster than natural gas. It becomes very similar in terms of flow rate for a given diameter of pipe.

It is the main path people have projected for seasonal energy storage. In fact, there are no other alternatives as far as we know. The "skeptics" have a very limited understanding of what they're talking about.

search: >'Hydrogen Car'< @DDG : <https://html.duckduckgo.com/html/?q='Hydrogen Car'>

Not interested in hydrogen as energy storage for cars. Also, I know how to do a web search. Are you a bot?

>Not interested in hydrogen as energy storage for cars. Also, I know how to do a web search. Are you a bot?<

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Merely demonstrating Real-World hydrogen storage, Given mobile-storage is more difficult than static-storage.

The 'Search' gives the 'Reader' the discretion to decide for themselves the Facts.

Bleep Bleep, Blop Blop, I am not a Bot!

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