Spain Blackout Is The First Of The Clean-Energy Era

Solar energy was powering the grid in Spain and Portugal on Monday—until it wasn't, leaving tens of millions without electricity.

- Matthew Dalton & Ed Ballard

This week's blackout in Spain and Portugal confronted authorities with an unprecedented event: the first mass electrical outage on a grid largely powered by wind and solar energy.

Spanish officials said Tuesday that they still didn't know what caused the outage, which left much of the Iberian peninsula without power for hours and disrupted everything from factories and trains to ATMs. Power supplies were largely back to normal by Tuesday morning.

The moments before the blackout, at around 12:30 p.m. Monday, were a window into Europe's energy future, dominated by emissions-free but fluctuating generation. Spain's electrical grid was humming with solar power—nearly 60% of total generation—on a largely cloudless day. Wind turbines provided another 9%. Wind and solar were so abundant that electricity prices were pushed into negative territory.

European Union economies have been investing heavily in both technologies, aiming to generate 69% of the bloc's power from renewables by 2030. But grids running on high levels of solar and wind face technical challenges that grid operators are still figuring out how to manage.

One of those is the loss of so-called inertia. Conventional power generation turbines take a while to stop spinning, buying time to balance electricity supply and demand if something goes wrong. If a solar plant goes offline, output goes to zero instantly.