[shawabawa3]

> There is a massive cost to starting and stopping gas plants that you are also not accounting for

It's my understanding that basically the entire point of gas power plants is that they are very cheap to stop and start (as opposed to e.g. coal or nuclear), at least, that's the case in the UK - are these plants different in the US?

[infecto]

Your understanding is mostly wrong then. Modern combined-cycle turbines are more efficient but I would not call them cheap to stop and start. You are still looking at a 20-30min startup time and a similar cool-down period. So yes designed to be able to shutdown I think the general range is an on-time of 30-70% but I believe with those ranges you get different efficiency curves. You get increased wear, higher fuel cost and also need to predict that demand will not spike. When prices dip below zero it may be more cost effective to keep the plants online.

[jillesvangurp]

It's still expensive relative to batteries. If you think about it, a steam turbine has a lot of water that needs to be heated before you actually get any steam and a lot of heavy, moving parts that need to start spinning. Once all that is up and running it's fine and you just expend fuel to maintain the steam pressure.

But this takes a while. And to heat things up faster, you simply burn a massive amount of fuel; which is costly. And until you generate steam, it's not actually generating any power whatsoever.

Any thermal plant has this overhead that makes starting them expensive and stopping them undesirable because the shorter you run them, the more inefficient they get. You amortize the startup cost over the runtime. The longer it runs, the better it gets.

A battery provides power within milliseconds and it can switch from charging to discharging on a moment's notice as well. That's why batteries are displacing gas plants as peaker plants in a lot of places.

[sschueller]

Pumped water storage or hydroplant can go from zero to 100 within tens of seconds. No degradation in storage capacity. Also greener than digging up all these rare earth metals although it still has an initial impact on the local eco system when you store water where it previously wasn't.

[jncfhnb]

A gas power plant (specifically a peaker plant designed for this) is still more expensive to start or stop than a battery or hydro.

However, it is much more expensive to build the capacity for batteries and you need to charge the batteries with excess power that’s available cheaply during surplus times.

The advantage of a peaker gas plant is you can build it big and shovel fuel into it that you just brought over from wherever. Many of them were built with the expectation that they would not face competition from batteries, so the economics of running them is getting bad. However they’re still important as a backup because you cannot depend reliably on the batteries being charged.