Flessibilità e resilienza: i nostri "assi" in tempi straordinari

In the last two decades the global economy has been gripped by the ‘disruptor’ – the nimble start-up that transforms an entire industry. But in 2020 we have all witnessed the arrival of the ultimate disruptor: COVID-19 – a global pandemic that in a few short months has changed every aspect of social, cultural and economic life.

Power grids are no exception. Dramatic changes in human behavior have produced huge fluctuations in demand for energy, prompting surprises for the sector and arguably accelerating steps towards the future of power by five, if not ten years. So, what have we learnt and what will COVID-19 mean for the future of power grids?     

The first and obvious consequence of lockdown was a decrease in electricity demand. Fig. 1 shows the situation in selected countries in mid-April 2020, where falls in demand as high as 30% were seen in major economies like France and Italy. A loss of load in the range of 30% may be considered as a relief for the power system, but such fluctuations actually present a major operational challenge. The fact that power systems did continue to operate was thanks to a lot of interventions by the operators and shows us two things: systems could be stabilized in extraordinary situations, but at the price of many manual interventions. 

However, in India the situation was even more extreme. On 5 April, Prime Minister Modi asked the nation to switch off the lights for nine minutes as a sign of solidarity in the crisis. With just 48 hours’ notice, network operators faced a monumental challenge – the moment when a population of approximately 1.3 billion turned the lights back on in one go. Remarkably, and thanks to thorough preparation by the transmission system operators, there was no disruption to supply caused by the sharp ramp down and ramp up (from 117 GW to 85.30 GW) within a span of four minutes. And again: managing the extraordinary situation was possible, but only because there was still enough time for humans to take manual actions.

An important realization for network operators that has been brought about by this crisis, is that in the future, it will be possible to operate power systems with even higher shares of renewable energies than today, and in a stable and secure manner. We have seen this in some of the countries most affected by the virus, who are also pioneers in solar and wind power. Lower demand in combination with continuously increasing capacity of renewable power resulted, for instance, in Germany, in a share of variable renewables of nearly 55% during the first quarter of 2020 [1]. In the third week of May 2020 the average share has risen above 69%, comparing to just 50% one year before (fig. 2). In fig. 3 we see the peak share of variable renewable generation in the load in several European countries – across all the proportion of renewable energy is notably higher on the year. Obviously, systems could be operated stable at these high shares of renewables, but experts should now analyze in detail, what they can learn from this unexpected experience, which opens in fact a window into a future about five to ten years ahead.

If the crisis has shown us anything it is the vulnerability of a globalized economy, reliant on global supply chains, power systems are not yet that global and during the crisis, electrons have continued to flow even as governments have closed borders. However, in the future we know that power systems with high shares of both distributed and highly concentrated renewable energies will depend even more on international cooperation than today. At that time, a COVID-19 style crisis could severely disrupt a region’s electricity supply. Security of supply therefore will require much more international cooperation and commitment. Greater collaboration and responsibility sharing must start now. 

If we look at the learnings of recent weeks and months, it is clear that the power systems industry will need to embed two key assets into the future development of the grid: flexibility and resilience.

In terms of flexibility, COVID-19 has shown that traditional security concepts like fencing control centers struggled under the circumstances of the pandemic. Flexibility to enable operators to work from other locations, either at other network operators, at software vendors or even distributed at home may help and should be considered. Of course, this will require careful planning, particularly with regards to cybersecurity, but this will no doubt prove to be a worthwhile investment.

Flexibility should allow us to respond faster to unexpected situations. As seen in India on the 5 April, essential measures to shore up the grid had to be put in place manually, but in the future technology should help more in such situations. Autonomous grids should offer up solutions automatically and at least provide decision making support.

The need for our second asset, resilience, is best derived from the vulnerability of global supply chains observed during the Corona crisis. Of course, energy systems are also based on global supply chains, but in contrast to other industries, national policies are used to mitigate the risk of interruption of supply by local reserves. Countries stored gas, oil or coal for weeks or even months, and conversion of these energy carriers to electricity used to be local. But with the increasing dependency on geographically concentrated renewable energy this concept needs to be reviewed. Future power systems will be more interconnected, and they will be operated closer to their limits – and by that be more vulnerable. And as there is no way to store wind, solar irradiation or also electricity in larger quantities, new concepts are required.

Resilience, i.e. the ability to ride through critical situations instead of focusing on avoiding them, therefore will become more important. This applies particularly wherever systems are becoming more complex and potentially vulnerable by more interconnection. In the future, more digitalized systems will be more dependent on communication infrastructures. Resilience in this case would mean, that they can still provide a base functionality in case these infrastructures are not available.

Maybe even more important, as indicated in fig. 4, power systems should be able to fall back in a mode using locally available sources in case the transmission grid is not available. Even if local generation capacity is insufficient to cover local load completely, supplying critical infrastructures, such as water supply, hospitals or telecommunication networks, would be essential as the minimum. 

Summarizing, if COVID-19 has taught us anything, it is that we have remarkable power systems across the world, led by talented people, that have been able to withstand the most extraordinary of circumstances. But in the future, a more renewables-based system built on international co-operation will require even more flexibility and more resilience. These properties will be the ‘aces’ up our sleeves in ensuring affordable, reliable and sustainable energy – but we need to act now to make them happen. It’s a challenge I look forward to. 

References

[1]      https://www.pv-magazine.de/2020/04/02/fraunhofer-ise-erneuerbare-mit-fast-55-prozent-anteil-an-der-nettostromerzeugung-im-ersten-quartal-2020/

[2]      Fraunhofer ISE, Energy Charts (https://www.energy-charts.de/index_de.htm)