For anyone thinking negative prices is a good thing: It's not. It's a panic signal because there are no takers for an oversupply of energy, making the grid unstable.
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.
This is all actually beneficial. It creates real economic pressure for just about everyone to build and install more batteries everywhere to profit from the price swings.
Most importantly, it motivates the wind and solar producers to buy up batteries and install them on site, so that they can shift the times where they sell power to the grid to times of day where its more profitable.
1) Commercial entities generally try to sell their products for a profit (positive price).
2) Negative prices make this quite hard.
3) To get back into positive profit, they're going to need to charge a higher price later on.
There are 3 ways the overall market can go if prices are negative - either prices go positive at some other time to make up for the losses the power providers are making, someone figures out a use for the free power and the price stops going negative or power providers go out of business. Typically what this seems to result in for renewable-heavy grids is occasional (even regular) negative wholesale prices and some impressively high retail prices. Free electricity turns out to be very expensive; it shows the grid isn't coping.
2. Isn't cheaper electricity a good thing for the manufacturing industry?
Yes, and that is in fact done. However, there it is still a bad deal with negative electricity prices.
> Isn't cheaper electeicity a good thing for the manufacuring industry?
It technically is, but its not as simple as that. Industrial manufacturing is a relatively steady load, which means the consumption is constant. The lowest prices do not matter all that much, the average price does. And that average price is relatively high here, even for industrial consumers.
> "They could export the surplus"
Transmission capacity and interconnectors are usually the bottlenecks.
It doesn't seem that hard. All you need is a load, but obviously harder as you increase the scale.
Heck you could build some large bodies of water and boil them from time to time.
Some suppliers already do that. When a power plant also supplies the city heating, it makes sense for them to put the power surplus into pre-heated water which they can store and later distribute to the buyers of the heat.
Obviously this needs some huge and well insulated tanks.
Here's an article (in Polish) about one built in Warsaw, 10TJ capacity: https://globenergia.pl/najwiekszy-wodny-magazyn-ciepla-w-eur...