There are historical accounts of volcanic activity blocking the sky, I think in Europe, for a few years. For all we know it was the whole planet. That would definitely disrupt solar energy collection without being an extinction level event.

Diversity is a genuine factor of fossil fuel free energy generation.

then I think we have bigger problems

Care to point them out? As I've said, and expect to be common knowledge on a (I would expect) scientifically leaning community, the dinosaurs weren't killed by the meteor, their death was caused by the blacking out of the sun. You have access to energy, you can make air filters, grow food, purify water. If you don't have energy, then you die.

Regardless, this is a deflection from the main point, that was merely an extreme example, even volcanic eruptions could cause huge disruptions if you depend too much on solar power.