so a fun thing about an electrical grid is that it needs to be balanced. if you consume more electricity than you produce, the frequency (of the alternations in an AC system) drops. Similarly, if you produce more than you consume, the frequency will increase.
This is very very very bad if you have a lot of expensive heavy machinery (like generators) hooked up to the grid, and can cause extremely expensive damage that is very difficult to repair. if you get too far of balance, it can even take down the entire electrical grid.
thankfully, this load imbalance can normally be managed, by incentivizing consumption or increasing production or any number of other interventions. electric utilities do this management as part of their regular functioning, so most people never need to think about it.
unless you go and hook a bunch of solar panels up to the grid. and, to do it cheaply, you don’t install the equipment that would allow those panels to be
disconnected from the grid, in the event that you didn’t want to utilize their output.
so what this leads to is that, in order to prevent the excess electricity generated by these panels at peak generation times from completely destroying the power grid, you have to call up industrial power consumers (like big factories etc.) and tell them to run all their equipment to consume the excess power. this causes wear and tear on their equipment, and so you have to pay them to do this. this is what it means when “the price goes negative”.
so the culprit is ultimately the failure of industry and government to invest in the infrastructure that would allow us to properly manage having this amount of distributed solar power hooked up to the grid.
