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Comment by AndrewDucker | Hacker News Reader

What's their efficiency? I can't find anything on their site.

They claim ~65% round trip currently and think they can improve to 75%. Not great, but polysilicon solar panels are cheap cheap cheap so charging efficiency doesn't matter much.

It's being sold as a complementary solution to more efficient LFP cells (for evening peak shifting), and as an alternative to pumped hydro and peaking gas turbines.

That's just it, 65 - 75% efficiency is still a lot better than having it wasted or end up on the market at negative value for power wasters like crypto farms and Facebook datacenters to just use up.

It's better for crypto farms and Facebook datacenters to use the energy instead, the efficiency is higher. If it would be wasted then it would be worse than this solution.

The efficiency of crypto farms and Facebook is zero if not negative: energy in, dystopia out.

It would be better to waste the energy than to let them have it for free.

That's ideology, I'm talking about physics.

When you say something is "better" you are talking ideology, not physics. Why is crypto "better" than literally any other application which could use excess energy production? For example, carbon sequestration.

It's not that crypto is better, it's that using it directly is better from an efficiency point of view. If you used it for carbon sequestration that would also be better compared to converting it and retaining 65-75% of the energy before using it.

It all depends on what you would have used the 65-75% of it on, later. Used at 65% to displace carbon emission overnight would be overwhelmingly better than for crypto or Facebook.

That's great. I hope they can scale it up and mass-manufacture it.

Pretty much every iron chemistry has failed to reach market. I reckon they're probably just blowing smoke.

I really want them to succeed for the sake of the planet, but it's another "revolutionary new battery just five years away" story.

They're still shipping small volumes but ESS Inc. has at least delivered some of their iron-based flow batteries:

https://essinc.com/

They're one step ahead of the vaporware stuff you normally read about in that they are already operating at a scale worth noticing (no long lab level power but 100's of KW) and they are about to scale up to 5MW which will be a very important proof point if it can be done economically and reliably enough.

I completely agree about efficiency. For managing solar's "duck curve", efficiency is less important than cost.

As solar gets cheaper and cheaper, the ability to mitigate efficiency loss by just increasing the size of the solar installation gets easier and easier.

And HVDC lines coupling areas far away from each other can help to deal with overcast and even offset some of the day/night cycle.

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