Comment by horsawlarway | Hacker News Reader

Comment by horsawlarway | Hacker News Reader

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Home installations just cut it off. In both of these cases.

I did my own battery backed installation. When I'm underproducing I can shed load (I turn off my AC - almost always that's enough, and it's automated by relay). When I'm overproducing (ex - my battery is full and my load is still not enough to consume input) I just don't let the panels generate more current than I can consume.

Managing grid scale power is different concern, and not particularly relevant to small household generation. Especially not relevant in the 800W category for "balcony solar" (which is much smaller than what I'm working with).

Solar is fucking coming, whether you continue to shove head into the ground or not.

It's just way more affordable. Getting easily more affordable as batteries continue to improve.

I honestly doubt I'll still be connected to a local utility grid for electric 10 years from now, and I live in a region of the US that has considerably cheaper grid power than most areas.

The dilemma here for me is twofold:

(1) while it makes sense to me to distribute generation, because there are not really any significant economies of scale other than purchasing power, it doesn't make sense to distribute storage which, IIUC, has huge economies of scale.

(2) being fully off-grid where I live requires homes that can be heated in winter with heat pumps that require less than mid-winter generation levels. That means, in general, much better construction techniques than most current houses have. At our house, we generate 2x of our needs in the non-heating season, and 0.5x of our need in the heating season - covering that demand with a battery would be ridiculous.

I think there are some interesting conversations to be had with regards to your first point.

Our grid infrastructure isn't cheap. We need a huge amount of equipment to do the voltage conversions to make power lines semi-sane. We also need a ton of space, maintenance and equipment to run the wiring, install the transformers, handle substations and distribution, etc...

My suspicion is that if you account for that, local storage is cheaper. But I think we're still finding out where battery tech is going to settle.

I'd be having a very different conversation if we hadn't introduced LiFePO4 (LFP) batteries, and realistically - these have only been on the market ~15 years now, and only really generally available for 5 or 6 years.

These are already pretty incredible batteries. A bank them the size of a washing machine will power most residential homes for days, cost under 10K, and be very safe. Prismatic LFP cells run ~$100/kwh (not theoretically, right now: https://www.18650batterystore.com/products/eve-mb31-grade-a-...)

If we see a similar upgrade with Sodium (and it's looking more and more real, multiple commercial products have hit the market last year) - then I think a decade from now we'll really start to wonder why we're wasting so much land and spending so much on grid equipment if you can just install a small bank of batteries for a couple thousand dollars and call it done.

Will you still have economies of scale with storage? Probably. Will those outweigh costs to transmit that to where it needs to go? My hunch is no.

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On a darker note - individual generation and storage is WAY more robust to military disruption. No central location to bomb to knock out power for a whole city.

I don't think there's any particular economy of scale to renewables beyond amortising installation costs.

This is a really big component in most western countries, so big installations are always going to be more cost effective, but there's nothing special about storage vs solar or anything else.

I suppose storage is smaller, so you don't have to pay for much land like you would solar (and where homeowners are basically utilising an underused resource so they have a cost advantage in that respect)

My current EV has a 38kW battery.

When it's too worn out for car use (SoH around 60-70%), it's still perfectly enough to run _everything_ in my house for multiple days - except for the electric sauna, and I'm smart enough to turn it on if there are production issues :D

There's a reason why EV's will never be as cheap as the cheapest ICE shitbox. Just the bare metals in the battery are worth thousands when recycled, even more if the battery is still viable.

If you ever are looking to implement that EV battery as house backup, this repo might be useful: https://github.com/dalathegreat/Battery-Emulator

I did mine with it and old leaf 24kwh battery (~60k km). After all the safety margins I get ~15 kwh out of the battery.

Sorry, the consequences are too dire for me to delegate household battery control to a vibe-coded project.

I'm curious what your home insurance provider has to say about your installation.

The value of the metals will depend a lot on the battery chemistry. LFP batteries don't need nickel or cobalt and sodium-ion batteries can also replace the expensive copper foil on the anode with cheaper aluminium foil.

I'm somewhat sceptical that used batteries will ever be worth much other than as scrap given the cost and complexity in testing, installing, and managing a mixed set of used batteries in larger installations.

With new batteries halving in price every 4 years or so the value of the raw materials in old NMC batteries alone should make it economical to sell for scrap and buy new batteries for stationary use cases after 10 years or so!

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