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173 points rbanffy | 2 comments | | HN request time: 0s | source
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hn_throwaway_99 ◴[] No.42128314[source]
Perhaps someone with more knowledge can comment on why solutions like these can't be used to solve the energy storage problem. Is it just economics?

That is, renewables are now the cheapest form of energy by a significant margin, but they are unreliable with respect to timing, so a storage solution is necessary in order to provide electricity on cloudy days when the wind isn't blowing, at night, etc. Most of the research I've seen into solving the storage issue involves batteries or things like pumped hydro. If things like solar and wind were "overbuilt", could a solution like this be used to create hydrocarbons when there is excess electricity? Power prices already go negative in some places when it's particularly sunny/windy. If the excess energy at that time could be used to make gas that could then be utilized by gas plants, well then there is your net 0 storage solution.

I'm assuming solutions like this are uneconomic (and similarly with hydrogen plants, e.g. by using the excess renewable energy to generate green hydrogen by electrolysis for storage and later use), but I'd like to understand better why.

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1. gipp ◴[] No.42128417[source]
> I'm assuming solutions like this are uneconomic

You kinda answered your own question already, I feel. The energy efficiency of cycling a battery (70-90% for grid scale) or pumped hydro (70-85%) is simply much, much higher than chemical storage. Here's a pretty recent one [1] showing 23% efficiency even at lab scale, and as described in the article scale is a big drain on efficiency.

[1] https://www.nature.com/articles/s41467-022-29428-9

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2. jl6 ◴[] No.42128730[source]
We need massive amounts of medium-term seasonal (3-6 months) stable energy storage, and liquid synthetic hydrocarbons are not a bad solution. Low efficiency isn’t a dealbreaker when the inputs are free.