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Comment by jacquesm | Hacker News Reader

Wind and solar over production can be stored in superconducting loops (this is pretty common in places where the grid is weak and large amounts of windpower are connected), batteries, pumped storage, supercaps and a whole host of other possible storage methods. Compared to those Hydrogen production and subsequent conversion back into energy is pretty clunky.

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Depends on the energy. Back into electrical energy would be a waste in many cases (exceptions like cars occur). Pumps are maintenance parts and you need a a fitting landscape. Batteries are a solution, but having billions of them isn't viable as well, especially not under ecological considerations. Superconducting storage are only energy efficient if you neglect the required cooling, otherwise they can only fulfill their function as a small short time buffer.

I don't want advertise hydrogen, but it is the most simple form of potential energy in our atmosphere and I have the impression that fans of the accumulator feel threatened somehow. Sure, investments in hydrogen technology should not negatively affect research in batteries. But since they already have real economical applications, I don't see any issue here. There are numerous interests that would want more powerful batteries.

> Wind and solar over production can be stored in superconducting loops ...

Superconducting loops are definitely not the storage technology that will economically scale far enough to store weeks worth of energy usage of the attached electrical grid.

But weeks worth of storage (of energy, not necessarily electricity) is exactly what is needed to enable a stable grid based upon 100 % renewable electricity generation.

It may be clunky, but is it more expensive? Other than pumped storage, the options you listed sound expensive per Watthour, and pumped storage is not available everywhere. Hydrogen should have around 50% round trip efficiency from electricity back to electricity and it can (partially?) reuse existing infrastructure for natural gas.

> Hydrogen should have around 50% round trip efficiency from electricity back to electricity and it can (partially?) reuse existing infrastructure for natural gas.

It can't though, not without significant studies and possibly rebuilding them entirely: the temperatures and / or pressures involved are different orders of magnitude, and nat gas does not embrittle.

Industries have started trying to blend hydrogen and natural gas to transport the hydrogen, and even that's turning out to be rather risky[0] unless the line was designed specifically with that use in mind.

[0] https://www.sciencedirect.com/science/article/pii/S245232161...

That's unfortunate. I guess one has to upgrade the hydrogen to Methane to be able to seamlessly use the existing infrastructure. That lowers the efficiency a bit and increases capex. I'd like to see some studies that try to estimate end to end cost for Power-to-Methane systems, but I'm not aware of any.

Yes, compared to generation they are very expensive. But so is a hydrogen installation of any capacity. The trick is to have enough of it to be able to level the peaks in both demand and surplus production. You're not going to store days or weeks worth of capacity like that, the function is closer to a capacitor than it is to a long term storage medium.

> superconducting loops (this is pretty common

Is it? I'm not aware of any such installations, this sounds pretty cool.

First time I saw this was in 2006 in a US based windpark. What really struck me is how small that solution was compared to anything else that would store the same amount of power. I still have a picture somewhere, I really should dig that up.

You don't have to drown entire valleys and their communities to build gasometers.

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