Solar energy storage breakthrough could make European households self-sufficient

ooli@lemmy.world to Technology@lemmy.world – 389 points –
Solar energy storage breakthrough could make European households self-sufficient
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I wonder what's the volumetric energy density, historically that has been a bigger issue than gravimetric energy density.

@JohnDClay

Good question, this article is pretty fluffy, not a lot of hard data. Reads kind of like a fluffed up press release honestly.

According to their site:

A storage system of 3 m3 can store up to 10,000 kWh of energy

So about 3.33 MWh per cubic meter, 3.33 kWh per liter, or 3.33 Wh per cubic centimeter.

Hmm, if that's correct, that's even higher than liquid hydrogen, which would be really impressive.

Energy densities

Edit: Looks like their gravimetric energy density is 3.5kWh/kg

Edit 2: here's a comparison for batteries

Battery Cell Energy Density

Since it's solid hydrogen I think it's to be expected, however I didn't see any information regarding energy losses which I imagine would be quite high when you have those kinds of cooling requirements.

This is why I hate marketing pushes. If they're a good-faith business, the efficiency needs to be within shooting distance of reasonable against costs. But as we learned from the artificial meat industry (that ultimately admitted we've already probably reached lifetime price/quality/scale limits from the methodologies they're using) brutal honesty doesn't get you investors.

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Thats in the ballpark of a year of usage from a household. Neat if true.

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The article is light on details, but it claims they're storing the hydrogen as a solid - not as a gas. Solids are generally about a thousand times more compact than a gas.

That's hardly a revolutionary thing - there are hydrogen powered cars on the road and those don't use hydrogen as a gas either. Those cars don't make much sense compared to lithium, but mostly only because there's almost nowhere in the world you buy hydrogen for your car. That's not an issue if you're producing your own hydrogen at home.

They don't? When the Toyota hydrogen cars were introduced here around 2015, one of the issues were that a full tank of gas would dilute through the tank walls within a week. From the marketing material of the latest Toyota Mirai, it seems that they still use Hydrogen stored in gas form, boasting improvements in a 3-layer tank that is tested for 235% of the pressure that the gas is stored at, compared to 150% for regular gas containers.

They don't. They use hydrogen fuel cells to generate electric power.

Yeah and what does that have to do with the Hydrogen being stored in gas form? The fuel cell converts it, it isn't a storage mechanism. Hydrogen has a boiling point of -253C, are you saying that Hydrogen powered cars are fitted with a power hungry cryo chamber to cool down the fuel to a liquid form?

Hydrogen really really doesn’t want to be solid, so doing that requires extremely low temperatures. Seems pretty cool, but inconvenient.

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