That's not actually the key figure of merit, the problem isn't how long stored sources can be used but peak output.
> 1.5GW for 10 minutes? 15 minutes?
All of it for longer than that (none of the various utility-scale sources have a discharge that quickly), which is why power and not energy is the thing that is targeted. But it varies (utility-scale battery systems have a different profile [and differing within that by specific battery tech] than thermal storage which has a different profile than pumped hydro, etc.)
> Watts isn't a unit of storage
No, it's a unit of power, and the main problem right now is being able to meet needed output levels when other sources are offline. The concern is the depth of the trough that storage can handle, you need breadth too, so a substantial level of that comes inherently with depth, and the main concern is short-term variation.
> That's not actually the key figure of merit, the problem isn't how long stored sources can be used but peak output.
That is exactly the problem. Yes, output matter, too, but capacity is the main figure people are interested in. If storage system A can output 1.5 GW but only for 1 hour, and system B can output 1.5 GW but for 10 hours then these are very different systems.
> All of it for longer than that
And how long is it? Basically we're trying to find the area of rectangle. You're providing the height, but staying conspicuously mum about the width.
> The concern is the depth of the trough that storage can handle, you need breadth too, so a substantial level of that comes inherently with depth, and the main concern is short-term variation.
No, the concern is both depth and breadth. It's easy to build a battery system that puts out a lot of energy for a short period of time. It's hard to build a battery system that puts out a lot of energy for 12 hours.
That's not actually the key figure of merit, the problem isn't how long stored sources can be used but peak output.
> 1.5GW for 10 minutes? 15 minutes?
All of it for longer than that (none of the various utility-scale sources have a discharge that quickly), which is why power and not energy is the thing that is targeted. But it varies (utility-scale battery systems have a different profile [and differing within that by specific battery tech] than thermal storage which has a different profile than pumped hydro, etc.)
> Watts isn't a unit of storage
No, it's a unit of power, and the main problem right now is being able to meet needed output levels when other sources are offline. The concern is the depth of the trough that storage can handle, you need breadth too, so a substantial level of that comes inherently with depth, and the main concern is short-term variation.