The Spanish economy is underpinned by some of highest shares of wind and solar electricity generation in the world. As demand plunged amid the coronavirus lockdown, the share of variable wind and solar power in-feed to the grid can become higher than normal.
“This is an important moment for our understanding of cleaner electricity systems, including some of the operational challenges,” said the IEA’s executive director, Dr Fatih Birol.
Staying flexible
With weaker electricity demand, power generation capacity is abundant but TSOs still need to maintain the balance on the grid in real time. In fact, some of the most high-profile blackouts in recent times took place during periods of low demand.
“The abrupt slowdown in industrial and business activity across much of Europe has reduced electricity demand, but it is also depriving power systems of a key source of flexibility,” Birol explained. “Under normal circumstances, large-scale electricity consumers such as factories can adjust their usage to help balance the system,” he added, “but that option is hardly open today.”
When electricity from wind and solar is covering the majority of demand, systems need to maintain flexibility through fast-ramp fossil gensets in order to mitigate a sudden shift in supply. A very high share of wind and solar in-feed in a given moment makes maintaining grid stability more challenging.
Technical advancements allow renewables to also provide some degree of flexibility Wind power can be gradually ramped down when demand drops late at night. Some solar power can be shut off at noon when there is more than needed. The IEA indicated that “in time, electricity generation from renewables may no longer simply follow the weather but will have to be managed in an intelligent way in order to reduce costs and improve electricity security.”
Storing excess energy
Though new forms of short-term flexibility such as battery storage are on the rise, most electricity systems rely on fast-ramp gas peaking plants to provide flexibility.
“Today, most gas power plants lose money if they are used only from time to time to help the system adjust to shifts in demand. The lower levels of electricity demand during the current crisis are adding to these pressures,” IEA analysts warned. Hydropower hence remains an essential source of flexibility.