Coal is dead. Long live ... what?

[flickster]

So I read about all these different power plants being forced to close - what’s replacing their power output in the short term?

Are we looking at rolling blackouts and at least temporarily sky-rocketing electricity rates for businesses and residential consumers?

[Una_Persson]

No. Where grid stability is threatened, the various regional and national agencies (such as PJM and NERC) won’t allow the plants to close without suitable back. Case in point is FirstEnergy not being allowed to close some of its coal plants as early as they would like to.

[flickster]

Good - this will take multiple years to unfold

[Try2B_Comprehensive]

@Chronos

Actually, one advantage of natural gas is that it makes it easier to incorporate alternative energy into the grid. Wind is already in the same ballpark as coal for price per unit of energy; the problem is just that it’s not consistent. If the wind dies down, then something else has to start up quickly to pick up the slack, and that’s a lot easier for gas than for coal.

You can do the same thing with large batteries:

Last week, the U.S. utility AES announced that it will purchase 20MW worth of utility-scale energy storage from battery maker Samsung SDI

“BYD is pleased to partner with the City of Los Angeles and the LADWP for these break-through Energy Storage Stations–this technology will allow L.A.’s solar and wind power to have a firm-capacity and make them ‘relevant’ to the grid allowing the City to reduce their dependence on other fossil-based sources of power generation," said Stella Li, Senior Vice President of BYD.

But I have no idea how to compare relative costs between these technologies.

[Chronos]

The relative costs will depend on what sort of timescales you’re looking to smooth over and how much fluctuation there is in both supply and demand. In general, batteries will be more effective for shorter gaps and for smaller fluctuations, and gas more effective for longer and larger, but I don’t know just where the crossover point is. And of course, the fluctuations will also depend on how large a grid you have connected, and how the various fluctuations are correlated over the area covered by that grid.

[Try2B_Comprehensive]

I am not affiliated with these guys, but here is a PDF with a lot of neat photos and graphs describing some applications of large batteries to more localized peaking issues. In these cases I think they are simply charging the battery from the grid ahead of time instead of resorting to wind or solar or what-have-you for that, but in the long run I don’t see why all sorts of end-users (including individual homes or apartment buildings) can’t have their own solar-charged peak-smoothing battery backups. Very expensive up-front, but the kind of chemical batteries they discuss in the cite are purportedly decades-durable. The anodes just don’t corrode!

[Chronos]

At least one and generally both of the electrodes of a battery must corrode-- That’s how a battery works. What’s relevant for longevity is how reversible that corrosion is.

And longevity is just one of many factors to trade off in battery design. You might also, in general, worry about how much energy they can store, how quickly they can store or release it, how safe they are, and how heavy or bulky they are. Home systems have the advantage that the weight, bulk, and safety are much less of a problem than they are in, say, a car.

[Try2B_Comprehensive]

@Chronos

At least one and generally both of the electrodes of a battery must corrode-- That’s how a battery works. What’s relevant for longevity is how reversible that corrosion is.

Well, I don’t have full understanding of the zinc-bromide battery either, so maybe together we can work out a precise explanation for the rest of the 'dopers for the claim that the electrodes don’t corrode. From here:

The battery is made up of a Zinc negative electrode and a Bromine positive electrode separated by a micro-porous separator. An aqueous solution of Zinc Bromide is circulated through the two compartments of the cell from two separate reservoirs. The other electrolyte stream in contact with the positive electrode contains Bromine. The Bromine storage medium is immiscible with the aqueous solution containing Zinc Bromide.

The battery uses electrodes that can’t and don’t take part in the reactions but merely serve as substrates for the reactions. Therefore there is no loss of performance, as in most rechargeable batteries, from repeated cycling causing electrode material deterioration. “When the Zinc-Bromine battery is completely discharged, all the metal Zinc plated on the negative electrodes is dissolved in the electrolyte and reproduced the next time the battery is charged. In the fully discharged state the Zinc-Bromine battery can be left indefinitely.”

bolding mine. Short answer I guess is that the ‘corrosion’ is fully reversible.

For stationary applications I think the key point is that the storage capacity is effectively unlimited as long as you don’t run out of physical space. The last link has info on its discharge power and duration- again I am not an expert, but it looks to me like it can effectively replace the grid, within the constraints of its capabilities.
So… who needs peaker plants? Deploy municipal-scale batteries instead, charge them up at night from the coal plant if you don’t want to use wind and solar &etc, but peakers are not very efficient and I’d rather avoid them. Isn’t that the correct view?