[sir_bearington]

To put these in perspective, the US consumes 500 GWh of electricity every hour. Of the 23 GWh of existing storage, 20 GWh come in the form of hydroelectricity. 100 MWh of storage only amounts to 1.4 seconds of electricity storage. We don't need megawatt hours worth of storage. We don't need gigawatt hours worth of storage. We need terawatt hours worth of storage. We're 6+ orders of magnitude off between the amount of storage necessary, and the storage we can feasibly build.

[Armisael16]

Why would an continent-scale entity need days or weeks of power storage?

[stillyslalom]

For long-tail adverse events? It's easy to engineer power distribution systems for the average case, but unless we accept occasional brownouts as a cost of doing business, we need to build robustness into our generation fleet. Let's say we get another Krakatoa-scale eruption that reduces insolation (and thus drops solar & wind output while increasing heating demand). Some amount of firm generation (hydro, gas peaker, nuclear) is insurance against correlated failure in the global climate system.

[sir_bearington]

"Accept brownouts" really just means "keep using fossil fuels" people don't accept brownouts, they buy generators. At this point, it's better to just keep burning natural gas since combined cycle plants are 1.5-2x more efficient than diesel generators.

Hydroelectric is geographically limited, you can just build dams where people need additional power.

That leaves nuclear. And since nuclear costs just as much to run 100% of the time as it does to run part of the time it makes no sense to use it as a peaker. Just run it 24/7, and install less intermittent sources.

[pfdietz]

We already have days or weeks of power storage: natural gas in storage caverns. We could easily have hydrogen stored in such caverns.

The single salt formation near Delta Utah could store enough hydrogen to supply the entire US electricity demand for 30 hours.

[AstralStorm]

Even hours runs hundreds of gigawatts.

Spanning a continent only helps wind power and not solar power.

[Armisael16]

One day of power storage would be 12 TWh (using the 500 GW number in the post I responded to). That’s ~2.7 orders of magnitude time larger than the cited current installed storage, which isn’t even remotely 6+ orders of magnitude.

Even if you entirely ignore that hydro component and only look at the 3 GWh number, that’s still only ~3.6 orders of magnitude less than what we’d need for a whole day with no power generation whatsoever.

Their numbers are talking about enough storage to maintain current usage for half a year.

To your second comment: spanning a continent does actually help with solar, since the sun is up at different times on the two coasts - that buys you several extra hours of power each day. Also obstructive weather patterns tend to not reach that far.

[sir_bearington]

> That’s ~2.7 orders of magnitude time larger than the cited current installed storage, which isn’t even remotely 6+ orders of magnitude.

But almost all (~95%) of the installed grid storage capacity is in hydroelectric storage. The above commenter is posting in terms of battery storage in the 100MWh range. We would indeed need 6 orders of magnitude larger than this even to just have 1 day's worth of storage. Hundred megawatt hours vs a dozen Terawatt hours.

Also, the amount of storage could be substantially more than a day in a predominantly wind + solar grid. Part of variability is mostly daily, with the sun going up and down. But both solar and wind are also affected by weather. That requires much more substantial amounts of storage to get the grid through consistent days of reduced production. Estimates to provide a 100% carbon-free grid with renewables go as high as 3 weeks [1]

[Armisael16]

I'm assuming that your citation is meant to refer to this paper: https://pubs.rsc.org/en/content/articlelanding/2018/EE/C7EE0...

It says that 3 weeks of power storage would be required in total absence of a serious overhaul in transmission capabilities. I had assumed that was a clear, if unspoken, assumption when I was discussion continent scale entities.

Also, the poster you originally responded to was discussing the literal dozens of installations that singlehandedly meet the 100 MWh mark. HN guidelines require that I assume this was a simple failure of reading comprehension.

[sir_bearington]

Even a much more modest goal of provisioning a single day of storage would entail 11.5TWh of storage. Dozens of 100 MWh facilities is still in the single digit GWh range. That's six orders of magnitude. And this isn't even taking into account handling heating, industrial use, and all the other forms of tapping into fossil fuel energy besides electricity.

[andromeduck]

1. Weeklong disruptions are a thing and would occur in the event of month long plumes from forest fires, major volcanic activity or other long tail natural disasters.

2. Relying on such a tightly coupled national grid as required to deploy that storage is a recipe for disaster in the event of any war or unconventional conflict. A few shut down transmission lines or stations could cripple entire national economy.

3. Overbuilding completely ignores the very real human and environmental costs of doing so. Rare earths are not very green, forced labor as used by much of the solar industry not very humane. You are condemning millions today to hypothetical harm to thousands tomorrow. It's insanity.

[7952]

The Tesla giga factory is making 20 gWh per year. 10 factories for 5 years and we have 1tWh. And we would need to massively scale up battery production anyway for electric cars in a nuclear scenario. And remember that those batteries are one of the easiest technologies to deploy. You don't need much more than a grid connection, a substation and a concerete pad.