Comment by wlesieutre

2 days ago

Not an expert, but from what I read the expectation is for sodium ion batteries to get substantially cheaper than lithium, mainly due to material cost.

Lithium makes up 0.002% of the Earth's crust, meanwhile sodium is 2.36%, and there's quite a lot of it in the ocean.

https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth...

The main downside is power density, which for grid storage is not as big a deal as it is for vehicles. But it will still be some years of research on sodium batteries for the cost advantage and manufacturing scale to materialize.

AT grid scale, sodium quickly closes the gap on lithium. The safety overhead, active cooling, and physical spacing needed to control lithium’s thermal runaway risk eat away most of its energy density advantage. Plus, CATL is hitting cost parity between full sodium BESS and LFP BESS systems.

  • The other big reason is the longevity. LFP life span gives you about 2000-5000 cycles depending on where your application can't tolerate the capacity reduction. Sodium Ion can go to 10,000 cycles (27 years) with a 70% capacity reduction at that life.

    This makes financing a large grid scale storage plant look way better to the bean counters because the investment continues to work and make money, after the 5 year amortization, typical of a corporate investment. This will be the kicker IMHO.

    • > Sodium Ion can go to 10,000 cycles (27 years) with a 70% capacity reduction at that life.

      The article claims much better:

      > the company’s GS1.1 [Sodium Ion] system will store energy for 20 years, over roughly 20,000 cycles, and still retain 80 percent of its capacity. For LFP, a basic durability benchmark pegs them at 70 percent capacity after 8,000 cycles.

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I’d love a shed sized battery sitting on the corner of my property if it could give me 5-7 days of power.

  • I'm writing this from my off grid shack.

    I have 15kwh of lifepo, and even if it weren't hooked to 4kw of solar I could still run my fridge, charge my phone, and run the fan in my fireplace for 4-6 days... longer if I dump the fridge.

    It's 6U of deep 19" rack space.

    So 2 x that isn't an entire shed-sized battery.

    Though I'd happily have a shed-sized battery... I suspect that delivering and covering something that size would cost more than the batteries I already have, though.

    • > It's 6U of deep 19" rack space.

      If the GP commenter is typing in from the UK .. that's a not uncommon garden tool shed size.

      By contrast modern Australian farm sheds have clouds forming within them and host birds that seasonally migrate from one side to the other.

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    • They make hyper-insulated refrigerators for use on ships with limited electricity that use either vacuum insulated panels or aerogel insulation.

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  • For something like a battery backup that last decades that doesn't need maintenance, maybe you could bury it out of the way (like under a deck or lawn?), maybe even under the frost line.

    • Underground is a big problem with it comes to water permeation and flooding.

      The other potential problem with a lot of energy systems that use things that have hydrogen in them is running power over the systems for long periods of time can start to leak hydrogen. You'll always want to ensure you have ventilation to ensure whatever is outgassing can escape the system. You'll end up with explosions, hydrogen embrittlement, or interesting corrosion in ways you didn't think were possible.

    • might need to be in some special containment at that size, depending on the technology -- some sodium ion battery implementations are very toxic / highly reactive / flammable.

  • That would you pay for that shed size battery?

    • Depending on just how much more cost effective sodium battery tech gets, that might not be a questionable proposition

    • I mean, I pay around $2,000 (AUD) per annum for electricity from the grid.

      If this battery plus some solar panels could get us free power for the next 20+ years, that's easily worth $15-$20k or so.

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>The main downside is power density, which for grid storage is not as big a deal

It matters less but it's still a big deal though. You need to inject the power near where you need it otherwise you have to upgrade everything between you and them, roughly speaking. So you can't put your battery in BFE where land is cheap.

Cost increases from that plus environmental and site development regs (which are always more in denser areas) screw you too. So between the upgrades and the overhead there might not be a valley of profitability because all the sites you could toss a battery on and the sites where someone who has a more $$ use case than you will outbid you on the raw land.

So the end result is you wind up having to shoehorn a bunch of little developments into small crappy parcels but then the fixed costs of development come back to bite you so density matters there because the more jiggling electrons you can pack in the more revenue you can have to offset your fixed costs.

That said, anything that lets you tell the NFPA, the environmentalists and the local screeching Karens to take their setbacks and shove them hugely improves density, especially on small sites, so the reduction in cooling needs and runaway protection that sodium gets you might make it denser once the tech is fully vetted. Every foot you can shave off the effective footprint of a battery (after accounting for fire setbacks, service space, etc) hugely increases the number of sites that are developable.

  • > You need to inject the power near where you need it otherwise you have to upgrade everything between you and them

    Or you install them near your solar/wind farm (or where the power connects to shore, if it’s offshore). If it’s a shore install, you might run a desalination side business when you have surplus energy.

A dystopian possibly impractical dream.. imagine a pyramid like structure in every neighborhood, made from blocks of such cheap sodium ion batteries, the outside of the pyramid is covered in soil and greens, the top which could even be a windmill. The green space is for walking around, kids playing, a few bike trails, whatever fun. The whole neighborhood is power buffered through this pyramid. The national power grid only needs to supply these pyramids.. with renewable energy. The houses, parking lots etc have solar panels that feed into the pyramid.

  • If you make them with Lithium batteries every neighbourhood can have their own volcano.

    I’ll show myself out.