Is the power grid prepared for extreme weather events?

Weather events such as snowfall, storms, floods, tornadoes or fires, once sporadic and exceptional, are becoming increasingly frequent, intense and unpredictable around the world. 

In Spain, tropical cyclones, heat waves, storms and depressions are becoming more and more frequent. We recently experienced the consequences of storm Bernard in Andalusia, storms Juliette and Betty in the Balearic Islands and a historic heat wave in the Canary Islands.  

Island systems are the most subject to extreme variables, but floods and freezing conditions are also common in the Iberian Peninsula. Meteorologists agree that there will be more and more tropical storms, because "the winds are learning which way to go". In other words, they are no longer one-off and isolated events, but once they have happened, they are more likely to become recurring.

The cause: Climate change

Global warming caused by greenhouse gases is causing these extreme weather events to occur repeatedly, as indicated in a report prepared by the United Nations Intergovernmental Panel on Climate Change (IPCC).

Faced with this reality, there is growing concern, especially in Europe and the United States, about the impact that these events may have on the electricity infrastructure and how they may affect energy security and the continuity and quality of supply.

A report entitled The Coming Storm – Building electricity resilience to extreme weather undertaken by Eurelectric with the technical collaboration of EPRI (Electric Power Research Institute), shows that in the last 30 years there has been a significant increase in Europe in the number of natural disasters and the events known as "extreme weather events".

This increase makes it necessary to invest in a resilient electricity grid. Monitor Deloitte, in its 2021 study "Connecting the Dots", estimates that investments in Europe for grid resilience may be close to €33,000 million. To put this figure into context, it is important to know that in the 1980-2019 period Europe suffered losses of up to €15,000 million per country.

The Electric Power Research Institute (EPRI) has carried out a series of analyses to understand how to deal with grid resilience in an efficient and focused way. It has recently been stated that: "As more of the energy economy depends on the electricity sector, it will be necessary to increase the reliability and resilience of electricity supply to meet society's expectations."

 How Extreme Weather Events Affect the Power Grid

The electricity grid is designed and built in accordance with technical standards based on historical analyses of environmental conditions. Among other parameters, historical average temperature, average rainfall and wind speeds are taken into account. Likewise, and as a very significant variable, the level of lightning strikes due to storms has been "mapped".

Increasingly frequent extreme weather events are impacting the grid. The strong winds that accompany storms can knock down power lines and poles or cause trees and branches to fall on cables with the resulting power cuts. Extreme temperatures, intense heat and frost can also affect the operation of the grid.

Because of all the above, and in order to deal with the effects of climate change, as well as progressing towards decarbonisation and electrification, electricity systems need to be adapted so they are able to withstand extreme weather situations, with the collaboration of both regulatory and general authorities. If the grid is resilient it will be possible to cope with extreme weather events and reduce the impact on the electricity supply.  

The Network's Response to an Extreme Weather Event

From an operational point of view, in the face of evidence of an extreme weather event, preparation and action is divided into five major phases: Prevention, planning and being prepared; insulation and the automatic restoration of sections of the electricity network; critical on-site repairs; final and wide-ranging repairs; and finally closing and assessing the event.

It is essential to ensure prevention on network assets and elements surrounding it. The technical pruning of trees, for example, is undertaken regularly in order to prevent branches or the trees themselves from falling on the lines by avoiding the so-called "sail effects" produced by very dense canopies.

This pruning is carried out in a way adapted to each species and its characteristics and is beneficial not only for the maintenance of the electricity grid, but also for the health of the tree itself.