Anonymous wrote:It’s complicated, and this is a massively simplified version, but the answer is that electric transmission systems have very little (as in almost no) room for error. It’s been documented that the voltage on the Spanish grid was oscillating up and down beginning around 9:30 am and it got increasingly worse until around 12:30 when basically everything shut down. If anyone officially knows for certain why this happened they aren’t saying, but oscillations like this have been documented on systems with a high % of solar power (there’s a theory that it has to do with the way distributed solar systems push power into the grid). Solar power is generated as DC power and has to go through a converter to go onto the grid as alternating current. The converters have very little flexibility and zero inertia. They’re either on or off. In comparison, a coal or gas plant has a huge turbine that spins, and the inertia of the turbine means the plant can absorb changes in the system without tripping off completely. Whether the solar farms themselves caused the oscillation (some experts think they did) or whether it was caused by something else, having 78% wind and solar certainly exacerbated the problem since there was so little inertia on the grid. When there was no inertia to dampen the oscillations & they got too extreme, the converters tripped the wind and solar off line, and the system couldn’t absorb losing almost 80% of its power at once.
This is definitely part of the issue, but the real whole story will not come out for months. Yes, it will take months for power engineers to do a full analysis.
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