Germany will soon produce enough solar power for most of the county from noon to 2 pm. This could destabilize the grid. Supply and demand must always be in perfect balance. Huge amounts of solar suddenly coming online means traditional power must cut back instantly (and then ramp up in microseconds when clouds block the sun) which is not something they are designed to do.
As Citi’s Jason Channell writes, “any further installations beyond this point could push structural solar power supply above demand and cause permanent mid-day grid instability.”
Here’s what he’s talking about (“double penetration” refers to Germany having doubled its solar capacity): Without batteries, that bulge is literally disruptive because it eats into conventional baseload generation, the backbone of current supply needs.
Germany needs a smart grid, which manages supply and demand better. Most of all, it need battery storage for excess solar power. Battery storage is improving. However it’s still expensive, barely deployed, and there’s a long ways to go and a short time get there.