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Comment by kumarvvr | Hacker News Reader

These are fascinating batteries. Yes, their energy density is less than Li-Ion but, are most suitable to cater to intermittent power sources such as Solar and Wind.

Hopefully, with enough space, a solar or wind generating station can be turned into a base load station. I guess that's where data analysis and computing will help.

An intelligent power controller / charger could theoretically turn a single wind turbine into a miniature base load plant, i.e, a power source that supplies constant power, buffered by these flow batteries.

I am hopeful that with better materials, not only with the flow batteries be eco-friendly, but also more energy dense.

Also, in the future, such batteries hopefully could make an individual house completely grid independent.

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There's no real compelling reason to locate the batteries near the generator.

For maintenance free batteries, coupled with an intermittent power source and an intelligent controller, the whole system coukd act as a constant power source.

I think the point is, from the perspective of electricity grid maintenance, it doesn't matter much (given sufficient transport capabilities) if you stuff all the wind turbines on one end, and all the redox batteries on the other end of the country.

No need to integrate the production and storage solutionss at all.

> given sufficient transport capabilities

I feel like that is fairly big thing here. In practice power grid capacity is very much finite.

There's no reason you couldn't have region-local storage locations underground. There are lots of huge natural and artificial cave systems that would be perfect for temperature control of even enormous batteries. I don't think transmission losses to a regional underground storage facility will be a huge concern.

Not next door no, but they are going to have to be in roughly the same region, because power losses over long distance transmission become significant in pretty short order.

I think you put the batteries near the load point. Transmission losses are more painful for higher cost energy (battery storage), than low cost (excess wind power).

They don’t operate below 10c or above 40c due to their chemistry so unless your location has a very temperate climate 24/7/365 the energy density is the least of your worries.

The 24/7/365 aspect can be solved by moving them sufficiently underground. Underground environments are naturally the yearly average temperature of the surface.

And even if digging is too expensive, there's another option: buffer the buffer with a big tank of water. That is, put the tank of electrolyte inside an outer tank of water.

As long as your average temperature is between 10C and 40C, with sufficient volume of water you'd have enough thermal mass to ride out the day and night fluctuations.

In some climates, you might need to get fancier to try to nudge the temperature in the right direction. Hot climates shouldn't be much of a problem, but even if they are you could use fans or vents to create a system that's insulated and shaded during the day but open to outside air at night. In cold climates, you might want to have a greenhouse kind of setup to capture some extra heat and prevent convection cooling so it stays above 10°C.

This might work in Europe but not in the states where the summertime temperature might be around +25 and the wintertime temperature might sometimes reach -25. The lake where my parents live freezes thick enough to drive a pickup truck on it.

Read the parent comment again. As long as some of the time temperatures are in a viable range, it isn't a problem.

I would tend to disagree. Even if the water buffer is 20 feet thick, it will freeze all the way through, at least where I live. I mean you can buffer sub-freezing temperatures for a few days, a couple weeks, but not for 6 months.

Oh, and since water expands when it freezes - the container will rupture, too.

Hot climates are a huge problem because temperatures easily reach 40c in Africa and the Middle East and that is just ambient temperature you are forgetting the heat produced by the battery itself.

Li-ion doesn’t have this problem as much heck the PANASONIC NCR-18650 can be discharged safely even at 60c.

Battery capacity scales with volume, whereas external heating/cooling losses to the environment scales with surface area.

That means, for any large enough scale plant, the cost to keep it at a fixed temperature diminishes to insignificant.

Correct, and you can add arbitrarily thick insulation.

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