> But the price of energy can be negative

Is this a sign of over-investment?

Is it case that the metric we're using does not show the actual price? https://www.squeaky.energy/blog/the-unintended-consequences-... shows a way to get "free" electricity on a regular basis, while it still costs consumers a very non-zero amount. In the case of solar, revenue could be achieved through out-of-market payments (CfD, power purchase agreements, renewable energy certificates).

Or is it the sign that the nightmare battery dominated grid is starting to happen? https://caseyhandmer.wordpress.com/2021/05/20/the-unstoppabl... Battery operators can choose between strategies designed to maximize revenue, profit, competitive advantage, or competitor losses, over any given timescale and with almost perfect deniability.

(or is it something else?)