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Understanding Solar Energy

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261 points chmaynard | 1 comments | | HN request time: 0.212s | source
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Veedrac ◴[] No.43430833[source]
The author misses a perhaps unintuitive point: the cost of storage depends also on the cost of energy. By the time you've overbuilt 2x, a full extra 100% of your demand is sitting around literally free at odd hours.

Traditionally, moving energy around means batteries, and yes maybe your battery costs more than just generating new electricity from a less efficient new solar panel at odd hours. But batteries are optimized for energy being expensive, where losses are wasteful.

Consider this really simple, dirt cheap alternative: plug your free energy into a pool of water and collect the hydrogen from it. Burn the hydrogen later, and point the light at your idle solar panels. It's hellishly inefficient, but I repeat: the energy is free. You are only minimizing capital costs, at least until other people catch up and start shifting load some other way.

The sane point on this curve probably looks something along the lines of a mix of batteries and synthetic fuels powering existing fossil fuel plants. The nice thing about going all the way to synthetic fuels and not hydrogen is that long term storage becomes trivially cheap, so it starts offsetting your winter load as well.

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pyrale ◴[] No.43433329[source]
> It's hellishly inefficient, but I repeat: the energy is free.

Can you give pointers about who gives away hydrogen generation systems for free?

Because the cost of energy usually factors in the cost of amortizing equipment required to produce and distribute it.

> The nice thing about going all the way to synthetic fuels and not hydrogen is that long term storage becomes trivially cheap

Once you've financed all of the horribly expensive capital expenditure, and provided you disregard that operating costs actually require paying people to monitor, repair and operate that infrastructure, the rest is basically free.

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ben_w ◴[] No.43433404[source]
> Can you give pointers about who gives away hydrogen generation systems for free?

If you don't care about efficiency (because the electricity is free), a 9 year old can make hydrogen generators out of old pencils and jam jars.

Citation: me, I did that.

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pyrale ◴[] No.43433608[source]
I can also make some methane depending on what's on the lunch menu, but that doesn't mean cheap renewable natural gas is a solved problem.
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ben_w ◴[] No.43433693[source]
Do you really not understand the point I'm making here?

The technical skills needed to make a device that turns water and electricity into hydrogen are so minimal that they can be performed by someone too young for you to be allowed to employ them.

When you don't care about efficiency, hydrogen is trivial.

The limiting factor is how much electricity you can shove through the water, not human effort.

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hnaccount_rng ◴[] No.43435005[source]
To be fair the problem with hydrogen isn't the production (that is ~free, once you have free energy at least some amount of time) but it's storage and then usage. Storage is a fundamental physics problem. Usage is something where low efficiency may or may not be a problem, depending on the over provisioning that we applied at the generation and storage stages.
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1. Veedrac ◴[] No.43451400[source]
Storage matters for widespread direct-consumer use of hydrogen, but in the example I gave it's not a big deal: just put the electrolyzer next to the solar panels. You only need to store ~12h of hydrogen production, and burn it onsite.

A more realistic world won't be implementing the Dumbest Possible Refutation, and would overbuild solar less than this in the first place. In that case you do care a lot more about storage, and that's a large part of why I suggested ‘synthetic fuels powering existing fossil fuel plants’ would be a saner strategy. But what exactly that world looks like is in the details, and not critical to the broad point I was making.