Yes, but only for specific use cases. We can build utility-scale batteries for hourly or daily cycling, we can also build them for emergencies. We can't practically build them for running their respective sections of the grid for weeks or months.
Of course not. Daily cycling would be the most obvious use.
Best way to think about it is at the scale of a typical household. Average daily household energy use in the US is 29kWh. That means a battery of an average EV today (60kWh) can run such household for 2 straight days. Now let's say you wanted to run that household for 3 months - that is 45 such batteries.
With all due respect, that is a very unlikely situation. 3 months? Having installed quite a few offgrid systems, no owner has even posited such a thing and I can't imagine any economic justification for doing so.
... In the household example above I said you need a 2700kWh battery to run a house for 3 months, but it doesn't mean that you need a 2700kW inverter to do so - average load likely doesn't exceed 50A, or roughly 6kW (120VAC).
Agreed, also don't forget that it's not a real world situation.
Same thing with that Tesla facility in Australia - it is rated to generate up to X many megawatts for Y many hours, but if it runs at full capacity it won't be running for very long before it gets empty. Likely they have a 1:1 or close to that relationship between capacity and generation. You can double the battery, and you will run for 2 hours at full power instead of 1 hour... long way (and an unrealistic one) to go towards running it at "grid scale" for weeks or months though.
Yes, daily cycling, or nearly so is the best economic use of a battery bank.
.....Flooded lead-acid is least expensive per capacity upfront... and it pretty quickly becomes significantly more expensive than Lithium options if you need to use it for daily cycling as opposed to emergency backup. You basically can expect just 200-250 cycles out of those batteries before you need to scrap them.
Trojan FLA batteries made for RE use show a cycle life of 2000 if discharged to 50% capacity. Typical life is about 10 years if cared for, less if not.
That's at least 40 times shorter life expectancy than LFP cells (like I said, they aren't dead after 10k cycles either). Add the logistical complications due to the fact Lead-Acid is significantly less energy dense, and you end up with FLA's being 100x or more expensive.
Logistical complications? They need more room because of their lower density, but that's not a problem in stationary applications. Li-ion batteries are used in transportation because they're much lighter. And as John reminded us, there's that fire thing.
100x? Show me the math.
Utility scale as discussed earlier comprises of 3 separate problems. One is peaking - easiest problem to solve, and we already have the solutions.
The present solution is to buy peaking power, almost always at more than retail rate. Makes financial sense at the moment, but one can easily see why utility scale storage would be desirable.
Two is compensation for intermittent generation sources such as wind. And three is to compensate for seasonal changes in generation, such as reduced or no solar generation in the Winter time for some regions.
They're all intermittent. Wind and solar (output, that is) more so than baseline power sources such as nuclear, but less so than peaking sources. Pinning the responsibility for storage onto only a few sources limits the options. Looking at the magnitude of the peaks and valleys is informative, too.
Peak load for many utilities is usually more than 3x off-off-peak load. Penetration of the grid by wind and solar is usually much less than 10%. Peaking problems are obviously much larger than wind and solar.
