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Understanding Solar Energy

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261 points chmaynard | 1 comments | | HN request time: 2.474s | 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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1. Veedrac ◴[] No.43451373[source]
Hydrogen generation systems exist on the same balance. When the input electricity is expensive, you want to build them to be more efficient, and that costs money, in catalysts and low-loss reaction chambers and such. If a huge amount of energy at peak times is free, then the optimal point is very different, and indeed if you try to minimize capital costs you end up needing something barely more sophisticated than a kettle. Kettles aren't particularly expensive to run!

While competition will quickly drive this towards a more even balance, as cheap storage displaces yet-more excess solar buildout, the point of the argument was just to show why naïvely extrapolating to extreme overproduction (>2x) is misleading.