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Comment by Godel_unicode | Hacker News Reader

And induction cooktops, and home charging BEVs overnight…

my back of the envelope calculation based on current human energy usage and battery production, it would take more than 150 years to manufacture 5 hours storage capacity. Of course manufacturing capacity is increasing and efficiency improves with electrification, but so is energy consumption, plus you have to factor in battery replacements during that time... Ya its going be tough to do that.

It's a more complex calculation than that because not all the energy storage is going to use battery electric. Pumped storage hydro is often pointed to as one option for mass quantities over a long durations, and somewhat more esoteric stuff like low-friction flywheels comes up for "capacitor" type loads where what's needed is a cycle of a few minutes.

The advantage of the batteries is specifically in power density, which makes them suited for mobility and consumer convenience. But the more you get into seriously optimizing electrical storage for scale, the less it's going to be about one specific mode.

No offense to your envelope, but that feels like a silly assumption. We produced ~15GWH of batteries in 2010 and now that takes us something like 3 weeks? Planned capacity additions will make that a daily production amount by 2030, and each subsequent cell is cheaper than the one before. This also assumes Li Ion as the only game in town. Plenty of other more likely options (flow batteries, hydro, etc) are feasible on a 15-year horizon.

5 Hours of electricity is something like 13 TWh, so if we get to 5,500 GWh annual production by 2030, it would take ~2.5 years to provide 5 hours of global electricity storage. Handicap it all and double the electricity requirement and halve the annual production figures and it's still only 10 years' capacity to go to a 99% carbon-free grid.

No 13 TWh is just our current _electricity_ consumption for 5 hours. We are talking about replacing all energy consumption like heating with electric heat pumps etc. This would be closer to 100TWh. And google says our current production is around 600GWh of batteries per year. 91.89 TWh / 600 GWh/year = 153 years.

Yes there is pumped storage, but I wonder how much more of that there really is to develop? Plus damns are environmental disasters of their own. The other storage methods are speculative at best. I just wanted to push back a bit on the idea that "just" need solar + storage as many people seem to believe. It is a big ask, and I think we will need more. If we don't want gas plants, then nuclear could be a good option.

Nah, that's ignoring that this hypothetical is in a world with mostly renewable power generation. E.g. most of the energy in that mix you're referring to is oil/natural gas/coal -- and over half of that is lost before it reaches the first power pole or the drive wheels. Vastly more efficient electric devices will greatly reduce the amount of energy needed. E.g. a heat pump with COP of 4 needs 1/4th the energy as burning natural gas in a high-efficiency furnace. Yes it shifts that energy demand from natural gas to electricity, but total energy consumption still drops. Similarly, a gas Corolla getting 40mpg equals about 1.2 miles/kwh, whereas a Tesla Model Y is more like 3.5 miles/kwh, so again, even though there's an increase in electricity consumption, total energy consumption decreases by ~2/3.

My other point stands though -- even if you grant a much larger electricity demand, you can't just look at today's battery production capacity. There are pipeline projects that will 10x that by 2030 (which is what happened in the past 10 years). Even with pessimistic assumptions, you get to pretty reasonable time frames pretty quickly.

Yes efficiency improves with electrification (I said so above) but step back for a second. The premise of this was that 5 hours storage would be "good enough" but my original point is that with change in electricity usage brought on by bevs, heat pumps etc, that this may not be the case forever. What if it is 10 hours? Or 20? Also, you have to keep in mind developing countries rapidly growing energy demands. And yes, battery production will increase, probably exponentially.. until it doesn't, everything is an S-Curve in reality, so it all depends on what we can realistically produce.

> everything is an S-Curve in reality

The only thing that limits battery production is demand. There will be plenty of materials available and plenty of machine-makers exist. That S will go as big as we need.

That's the kind of logic that got us here.

The "there will be plenty of oil" logic got us here because it was right, so I'm not sure what you're implying. It doesn't reflect negatively on batteries unless ability to scale up is inherently bad, and I don't think it is.

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