LUNGILE MASHELE: What Spanish outage teaches us about renewables

Bent Flyvbjerg, a renowned scholar in the field of project management and planning, mentions four sublimes, or drivers, that characterise megaprojects. These are the technological, political, economic and aesthetic sublimes.

The technological sublime refers to the fascination with and faith in technology’s ability to solve problems and push boundaries. The political sublime pertains to the allure and impact of political power and ambition in driving megaprojects. Often these sublimes mislead us, and we quickly find out that the laws of physics are not malleable. 

At 11.15am on April 16 Spain’s power grid ran entirely on renewable energy for the first time, with wind and PV combining to generate 100.63% of total demand. On April 21 solar set a record, generating 20GW of instantaneous power — covering 78.6% of demand and 61.5% of the grid mix. 

A week later, Spain suffered a blackout. While the root cause is still being identified, the Spanish grid operator provided a timeline of events, stating that there was a loss of generation in the country’s southwest and that it was possible it was solar. This was the first event; 1.5 seconds later there was a second generation loss event.

This grid destabilisation went on to affect the regional interconnectors into Portugal and France 3.5 seconds later. Immediately after that 15GW of renewables went offline. This cascading loss of generators in just five seconds forced nuclear, gas and hydro plants to protect themselves by going into islanding mode. This led to a total system collapse, known as a blackout, and resulted in zero generation in Spain.  

During the next nine hours Spain found itself having to ramp up capacity to cater for the evening peak at 9pm with a demand of 35GW. By 6am, 99.16% of peninsular supply had been restored at 21GW — thanks to Morocco and France, which energised the south and north, respectively. 

This blackout has been termed the worst blackout in living memory, affecting more than 55-million people in several countries and lasting more than 12 hours. The truth is if you run a system that has a high penetration of variable renewable energy, that system requires a significant amount of inertia. This is costly — and few countries can afford the true tariff associated with high renewable penetration.  

Grid inertia refers to the resistance of the power grid to changes in frequency, which is crucial for maintaining stability and reliability in electricity supply. Grid inertia is primarily provided by large synchronous generators, such as coal, gas, hydro and nuclear power plants. 

Interconnected grids with large dispatch capacity, flexible generation, synthetic inertia such as batteries, grid-forming inverters, updating grid codes and hybrid power plants can enhance the stability and resilience of the power grid, ensuring a reliable supply of electricity in a low-carbon future. 

As the energy landscape evolves, so too must our approach to maintaining grid stability. SA has adequate redundancy in the system and a world-class system operator that has been managing the grid during periods of significant load losses. The Spanish blackout is exactly why load-shedding is implemented in SA — to avoid total system collapse. 

We dare not indulge in Schadenfreude, but we need to be honest about how an electricity system operates — pointing out the limitations of technologies is not climate denialism. However, leaving people without food, transport, water, telecommunications and money has economic and political consequences. 

Sublimes will not help the region when millions of people are in the dark. While the need to decarbonise is essential, we cannot jeopardise the continued reliability of our power systems while pushing the boundaries of physics. 

• Mashele, an energy economist, is a member of the board of the National Transmission Company of SA.