In the category of doing obnoxious things for shock value, why stop at merely making sure you have enough batteries to keep you covered during the *average* year? Why not make sure that your home is going to be fully self sufficient in 99.99% of years? That probably adds another 50-150% to the total amount of storage that you would need.

But also, the expensive thing about batteries is typically the amount of power they can produce. The post used lithium ion batteries as a reference point, and those typically have a power rating between 1 and 4 hours - meaning they can fully discharge an entire summer's worth of stored energy in 4 hours... which is probably not something you need to pay for.

If you want a ton of really cheap long term energy storage, you'd look into a technology more like hydrogen fuel cells. The raw power (for standard home, 10 kW is plenty overkill) is going to be more expensive than lithium, but for storage you just need a bunch of hydrogen stored somewhere safe (probably buried underground in your yard). That's much, much cheaper than lithium ion batteries on a per kWh basis, especially if you are scaling up into the MWh territory.

And, the other big cost saving solution is to just add more panels. It means you'll be overproducing in the summer and you'll have to curtail, but some curtailment in the summer is a lot cheaper than finding a way to ferry all of that energy into the winter. Then you have extra panels in the winter and you don't need as much storage to be fully self sufficient.

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cobbzilla a day ago | parent | next [-]

it would also be really cool to use excess power generation to drive atmospheric petroleum synthesis (pull carbon from air to make hydrocarbons); then sell it or store it for later use.

I know the tech is not quite there yet, but it’s getting closer every year.

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tpm a day ago | parent | prev | next [-]

Storing hydrogen at home is not going to be cheap though, is it? At that point it would be worth to look at storing eg methanol.

	▲	BizarroLand a day ago \| parent [-]
		Use heat and pressure and electricity and you can convert CO2 and Hydrogen into Methane. Methane when burned releases the CO2 back into the atmosphere, but if you're mining the CO2 from the atmosphere to begin with it pretty close to carbon neutral fuel. https://news.osu.edu/turning-carbon-emissions-into-methane-f...

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matthewdgreen a day ago | parent | prev | next [-]

Hydrogen would be a terrible approach due to the low round-trip efficiency and the need to store huge amounts of compressed/cryogenic gas, but iron air batteries seem like they could actually do this.

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Taek a day ago | parent [-]

Most people have the wrong idea about hydrogen fuel cells because the media almost exclusively talks about them in the context of cars.

When your fuel cell can be stationary and heavy and large, you can hit efficiencies above 50% without cogeneration and above 80% with cogeneration.

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matthewdgreen 20 hours ago | parent [-]

Does that number include electrolysis? I didn’t realize that kind of round trip efficiency was possible.

	▲	Taek 19 hours ago \| parent [-]
		Yes it does!

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vonneumannstan a day ago | parent | prev [-]

Yes I love having bombs buried in my back yard. Very exciting.

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cycomanic 21 hours ago | parent [-]

Why are you afraid of hydrogen? Compared to the lithium ion batteries or even the LPG or petrol for a generator hydrogen is very safe. It's a common misconception that hydrogen is dangerous. You can stick a flame into pure hydrogen and nothing will happen. It's only if you mix with oxygen that it becomes dangerous, but because hydrogen is lighter than air it's going to dissipate very quickly if you have a leak in your container (unlike e.g. Gasoline fumes)

	▲	BenjiWiebe 18 hours ago \| parent \| next [-]
		I'm afraid of hydrogen due to hydrogen embrittlement. I wouldn't appreciate my high pressure tanks turning into bombs (no ignition or O2 required).
	▲	dboreham 20 hours ago \| parent \| prev [-]
		The Humanity.