Comment by Zanfa | Hacker News Reader

Comment by Zanfa | Hacker News Reader

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> On sustainable energy sources: I, as many other germans, receive all of my electricity from purely renewable energy sources for more than ten years now. 24/7.

Grid-scale storage (apart from hydro, but that's basically maxed out or unsuitable for most geographies) is still an unsolved problem for renewables, even the largest lithium-battery ones are basically a rounding error. You'd need multiple weeks worth of battery capacity to really run on renewables. Not even sure if there's enough lithium to make this work theoretically with current tech.

> On nuclear: The cost of nuclear power is wildly underestimated

Same is true for every other power source as well. Energy storage for renewables is never included, so you need backups, the €100 billion German defence package announced a few months ago is a direct consequence of "cheap" Russian gas, the millions of people suffering/dying from air pollution related issues from using coal.

There's no perfect solution, but nuclear is definitely a strong contender for the best way forward.

> There's no perfect solution, but nuclear is definitely a strong contender for the best way forward.

Absolutely! But:

Nuclear was approximately as cheap as the equivalent LiIon storage a few years ago, but the batteries are getting cheaper and the reactors are not.

There are also other chemistries, and other storage options, which I'd include under the banner of "no perfect solution, so let's do everything".

> You'd need multiple weeks worth of battery capacity to really run on renewables.

I have no idea why this meme propagates. How many people live where there is no sunlight for multiple weeks at a time? And it's not like we don't already have some long distance power lines.

PV is so absurdly cheap that overproduction is seriously not a bad solution if you're just concerned about cloudy weeks.

It's a solved problem for Germany. Electrolyze Hydrogen, store it in the existing gas infrastructure for the winter. Use the gas plants to burn it in the winter.

That has a round trip efficiency of around 20-25 % I think (more if you can also use the process heat), so we would need to over-provision renewables by 400 % to make it work.

There is a ton of unused roof space that could be decked out with solar, though. There are few heat pumps deployed so far, lots of inefficient old houses that could be modernized, plus there is an array of concepts for other storage tech still at a pretty early stage. It's probably going to be a mix of different generation and storage tech coupled with gains in efficiency, and that seems like it could work out.

Sure, feasible in the long run but don't hold your breath on it to work in the next 5-10 years. China has just doubled their growth targets for solar so producers have trouble keeping up with demand already and we have almost no domestic production anymore, so there's just no way we'll be able to act on this in the near future.

I would love to see a reference about this being actively used, in a meaningful capacity (as in: enough to prevent a countrywide blackout).

There is no large scale hydrogen storage facility that could take even 1% of German's energy needs.

Yet.

Indeed. If the annual natural gas use of all of Germany was represented as liquid hydrogen, it would be a ~700m cube.

A year is probably more than is needed, but I don't know how low storage can go before it causes problems. If I guess a week is sufficient then every million German residents need a 43m cube.

This isn't unbuildable if there is sufficient political will.

We don't Electrolyse Hydrogen in Germany there is not one large-scale installation. You can't pump 100% hydrogen in the natural gas infrastructure, and the gas plants need to support hydrogen burning. You also need a surplus of energy, which Germany obviously not has.

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