Blackout in Spain, the collapse of renewable energy between the causes of the fall of the electricity grid

The first official explanations on the concatenation of events that caused the blackout in the Iberian peninsula yesterday, April 28th. According to the manager of the Spanish electric transmission network Ree (Red Electric de Espana) there were two faults. At 12.33 the network suffers from a loss of generation but then stabilizes. A minute and a half after a second episode of loss of energy generation. A few seconds later the electric interconnection between Spain and France due to the instability of the network is interrupted. Immediately after an imposing loss of production from renewables, the system hits and immediately after the network falls. Ree spoke of a « strong oscillation in the flow of energy, which triggered » a very significant loss of generation « . This loss of generation has gone beyond the management capacity of electrical systems and the Spanish network has been disconnected from the European system. The electrical system is then collapsed, causing voltage losses in the power supply points of the Spanish and Portuguese network.

The balancing node

Portuguese Prime Minister Luis Montenegro said that there is no indication of a computer attackbut both countries are still examining all the hypotheses. Also excluded another accident such as the fire or the sudden variation of temperature that were sustained on the day of the blackout (Here all the hypotheses).
The problem seems to be the overproduction of solar energywith a balanced problem between the amount of energy introduced into the network and that absorbed by the demand for consumption.

The technical explanation linked to inertia

At the time of interruption – reports Reuters – the Spanish network worked with very little « inertia », that is, the energy that moves in a large rotating mass as a generator or in some industrial engines. Inertia helps to stabilize the network by slowing down the speed of variation of the frequency when a sudden drop or increase in demand or production occurs. « In these conditions (when there is little inertia) if there is a decrease in production for any reason, the network loses (more) inertia and everything hurts. And in case of blackout, it is necessary to reconstruct inertia before bringing things online, which takes a few hours, » said the source of Reuters. The episode showed the complexity of the management of modern energy systems, especially when they integrate growing levels of intermittent renewable energylike the wind and sunny one.

The energy mix

Spain is one of the major European manufacturers of renewable energy and the interruption of Monday 28 April has already triggered a debate on the fact that the volatility of the supply by sun or wind energy has made the most vulnerable electrical systems to this type of interruption. Red Electric data show that solar energy provided almost 59% of Spanish electricity at the time of blackoutwhile the wind energy provided almost 12%, nuclear power almost 11%and the cycle gas plants combined 5%. Red Electric data also show that in just five minutes, between 1230 and 1235 local time, the production of photovoltaic solar energy has fallen from over 18 gigawatt to only 8 Gigawatt.