[ZeroGravitas]

This was one of the actual problems highlighted by the people who coined the term "duck curve" over a decade ago.

One of the main ways we've avoided this problem so far is that solar kept getting cheaper.

So it's not really a problem caused by cheap solar, it's just basic market competition, lots of supply with no barrier to entry drives prices down towards the long term marginal cost.

[m55au]

Right, but would not marginal cost approaching zero amplify this problem under the current market system (and without any other mitigations)? So not exactly causal, but making it from a small to a bigger issue.

[ZeroGravitas]

The issue was that the decarbonisation of electricity (and therefore society) would slow or stop before we'd decarbonise if expensive solar lost any of its market. Not cheap energy, that is a good thing.

Between batteries, wind, demand response, EVs etc. that slowdown doesn't seem likely to happen.

And the lure of cheaper energy expands solar out horizontally to new markets, speeding up global decarbonisation.

[m55au]

I don't think it will happen either, but I do think there is a bit of imbalance developing in the whole system right now.

For example a decade ago electricity prices in Nord Pool were relatively stable (and reasonable/lowish). Now it is quite common to either have 0 or even negative prices during summer and artificially set maximums in the autumn/winter. IIRC, the rules were that if the price hit 60% of the maximum, it had to be raised by 1000 €/MWh. It got to 4000 €/MWh (which is 4 € or $4.7/kWh) in 2022 and was supposed to be raised by another 1000, but it was decided not to do it, so I think it stands there right now. But in any case, this is a ridiculous price. As are the negative ones.