[_fizz_buzz_]

The grid is not unstable and it was also not unstable the last view days when prices were negative. Germany has one of the most stable grids in the world. Negative prices are good when you need to buy electricity and they are bad when you are selling, but of course generally in a functioning market there shouldn't really be too many days with negative prices. It does mean that there isn't enough storage currently on the grid.

[jbrnh]

They are working on that https://battery-charts.de/

[_fizz_buzz_]

Sure, and negative prices will send a strong signal to the market to hurry up with adding storage. So, this will probably be more of a temporary situation and in the future there will be very few days with negative prices, however there will then also be fewer days with very high prices.

[chongli]

Now what we need is a cheap grid interconnect for home users running solar panels that automatically starts charging a battery when grid prices go negative, to absorb that extra power.

[eigenspace]

That already exists

[red75prime]

Yeah, the curtailment is a simple way to deal with instability. I wonder who chooses which power plants should curtail their output. The Bundesnetzagentur?

[jerven]

The plants that are willing to give supply for the most negative price are the ones that will not be curtailed. So market forces. Basically at such points power plants are paying for the privilege to be allowed to supply power. This is dominated by restart costs and as such is often paid by classic "baseload" plants such as nuclear ones. i.e. they will accept losing money during one part of the day/week so that they can make money during a different part of the day/week.

[red75prime]

So, the economic incentives favor peaker plants and storage (natural gas plants, peaker coal plants, batteries, pumped storage).

[jerven]

Yes, and no, maybe ;) the economic incentives are designed to always provide enough power and no more at the cheapest possible point for that time slot. The market (if free enough) searches for that point over time. One possible solution may be peaker plants (this was financially so in the burn fuel age) another maybe overbuilding (e.g. your home backup or off-site generator power that are sized at peak load/demand, not the actual demand). All constrained by what is physically possible on a grid.

Peaker plants gamble that there are going to be peaks (sure financially plan for but they are not guaranteed to make their profits).

In the peaker plant categories the storage options are different from the spin options because the incentives are slightly different. Specifically battery storage is not just a peak plant exercise it is a grid connection optimization exercise. Grid connections limit how much power one can sell from a generator. A battery system can be placed on the grid or between the grid and the generator. In the case of between grid and generator, it allows a generator to run at it's optimal speeds more often than not, and sell more because one can guarantee a wider range of output for a longer amount of time.

Some of the first battery storage systems were sold to gas peaker plants because it allowed them more time to react. i.e. idle at a more efficient level their gas turbines or even shut them off and start them on demand.