Are we still heading for net zero and ready to abandon fossil fuels? This is how the grid was restarted in Spain.




Update: A day after the major blackout that hit Spain and Portugal, the Spanish TSO REE has confirmed that demand has been completely restored. While the root cause of the outage is still unknown, we can already analyze how the grid restoration unfolded — and what it tells us about system resilience.
How do you restart a power system after a total blackout?
This is known as a black start, and it must be carried out in carefully managed stages to keep grid frequency within safe limits. In the case of Spain, the following resources were used to get the grid back to capacity:
- Hydro and gas resources were among the first to restart the supply.
- The interconnection between Spain and France has also been crucial: More than 4 GWh were imported from France between 14:00 and 18:00 CEST. Imports from Morocco also contributed to the restoration of power supply in the evening, between 19:00 and 20:00 CEST.
Why not nuclear?
Nuclear plants were automatically disconnected for safety reasons and are typically among the last to rejoin the grid during restoration.
And wind and solar?
During the blackout, some wind and solar generation remained online and continued to support the grid in isolated areas, helping to prevent a complete system collapse. However, these sources currently do not support black start operations. Most solar PV systems lack grid-forming capabilities, meaning they cannot independently contribute to restoring the system after a total shutdown.