[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.

[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?

[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.

[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?