[mduerksen]

There is a working system commercially available in Germany, but it is pretty expensive [1]:

Long-term energy storage with hydrogen, with 1-5x 300 kWh. Which allows for full electric independence (not including heating though). Price: 85,000-125,000 €, minus government subsidies.

[1] https://www.homepowersolutions.de/en/product/

[ephbit]

Let's say you want to use the system for heating with a heat pump.

Your energy consumption for heating might be ~ 3000 kWh/month during the winter months (Nov-Mar) for a moderately insulated house.

Assuming your PV produces only 10 % of the demand during these 5 months (so you have to rely on stored energy for the remaining 90 %) and your heat pump delivers a Coefficient of Performance of 3.5 then you'd need to store ~ 3900 kWh.

As to my back of envelope calculation, one standard 50 l bottle of hydrogen contains ~ 30 kWh worth of energy when filled at 200 bar.

So you'd need ~ 130 such standard bottles to store enough hydrogen.

That's quite a lot. But of course with a well insulated home, you'd maybe only need a third, so that'd be 3-4 bundles (with 12 bottles each).

[pstuart]

That looks like exactly what OP was looking for. One would assume that over time and at scale the price would come down significantly.

Hydrogen embrittlement seems to be an unavoidable problem so not sure how that plays out.

[elsonrodriguez]

Looks like the system uses standard tanks. There's probably a scheduled tank replacement schedule.

[mcbishop]

Thanks, it's good to know about this picea system.

For now and maybe always, it's probably more cost-effective to size the solar-electric system for winter months (if adequate roof / ground space).

[mduerksen]

Its definitely worth it to use all available space.

Still, it definitely cannot generate enough to bring you through the german winter. Some example numbers I have read: A 10kWp solar system that generates up to 1,400 kWh in a summer month will only provide about 200 kWh in December.

[ZeroGravitas]

You can get more power in summer by using a vertical bifacial panel positioned E-W.

And if you position it N-S you'll get slightly less power than a standard setup, but it'll be less concentrated in the summer, and also spread through the day more.

https://www.sciencedirect.com/science/article/pii/S266695522...

[mcbishop]

Holy cow, seven times more energy in summer months. Hydrogen storage sounds compelling in that situation.

[tpmx]

So 57-83 €/kWh, or on average about 175x more expensive than the current already insane electricity prices in central Europe. This is the concept that will save us according to the (qoften German, for some reason) anti-nuclear fundamentalists who have gotten into this pickle in the first place.

[Ekaros]

At that price, wouldn't a diesel generator burning cooking oil be cheaper?

[tpmx]

Diesel in a diesel generator is already roughly on par with the current insane electricity price, dunno about cooking oil, but it's probably roughly similar.

[mduerksen]

You could have made the same argument against solar panels 15 years ago.

This is a pioneering product for early adopters - expect prices to go down significantly with economics of scale. And further research in this area is far from exausted.

[tpmx]

I mean, I don't disagree. The problem is that lots of anti-nucluear-fundies are comparing existing nuclear power to hypothetical hydrogen storage - "it's just a matter of research".

My point is: Deploy nuclear power now, continue RND on large scale hydrogen storage that maybe will pan out in 20 years.

[mduerksen]

Yes, I was not proposing such system as a large scale solution for the coming winter. It would be prudent to keep our nuclear reactors running for now.

As always, There is No Silver Bullet™.

Nuclear is not the perfect solution. It cannot be powered on and off on short notice, which would be useful for complementation of solar and wind that have high power output, but also sudden slumps. Ironically, the ideal companion for renewables would be gas...

Lithium batteries could compensate short outages, but don't have enough (feasable) capacity for long seasonal shortages.

Enter Power to Gas. Hydrogen can be a good tool in that area.

A commerically available hydrogen storage system (that is in high demand even despite its price point) will definitely accelerate innovation very effectively. I think this tool will be available quite soon for mere mortals.

[tpmx]

I'd add that it's also prudent to build new nuclear reactors now. The tech exists and there is a very clear lack of mostly plannable power supply in many countries/regions.

The tech for building reliable, safe, affordable, large-scale hydrogen "batteries" isn't here yet.

[mduerksen]

New nuclear reactors are also not here yet. They might become ready in 8+ years if started now.

So the solution is simple. Nuclear has its place. Power2Gas too. Build and invest in both. And in the meantime, use what we have without ideolgical eye patches.

[gamblor956]

Nuclear power plants take years to build. Even if a plant were approved today, it wouldn't be finished before large scale hydrogen storage either fails or takes hold, at which point it would be an expensive and unnecessary boondoggle.

[tpmx]

Reminder: You're comparing the construction of existing tech (nuclear power plants) vs tech that doesn't even exist: large scale, safe and affordable hydrogen storage.

You may find this interesting:

https://www.reddit.com/r/dataisbeautiful/comments/wvjfiy/how...

[adrianN]

Did you just divide the cost of a storage system by the amount it stores and then compared that to the cost of a kWh of electricity off the grid?