Solar panels are a blessing: they provide clean energy. So it makes sense that we are rapidly scaling up solar energy worldwide. However, this enormous growth also comes with its own challenges. The growing pains of the energy transition.
Where is the inertia?
Solar parks have one major disadvantage. They are too fast! Here's why: the electricity grid is a matter of balance. If there is a huge energy demand somewhere, more electricity must be generated at that exact moment. And vice versa; in the event of a disruption, power stations must quickly scale down. The old power grid mainly ran on large powerhouses: coal, gas and nuclear power stations. If these are shut down due to an internal disruption, the heavy turbines continue to run for a while. This gives the system time to restore the balance.
Solar and wind energy work differently. They respond directly to the sun or wind and cannot be controlled. This rapid switching is not a problem as long as it does not happen on a large scale and synchronously, and the network remains in balance. But in the event of a disruption, there is no room for that. ‘The problem is that we are now using the power grid in a different way than we ever imagined,’ says Johann Hurink, professor of applied mathematics at the University of Twente.
A delay that helps
‘The frequency of the electricity on the European grid is synchronised and controlled at a frequency of 50.2 hertz. As soon as the frequency deviates slightly from this, energy generators are automatically switched off. And with solar parks, this switch-off happens very quickly and synchronously,’ says Hurink.
Hurink and his multidisciplinary research group at UT are investigating how we can create space in the system again. Not by returning to old energy sources, but by making the grid smarter. With more conscious control. 'This must be done not only on the generation side but also on the user side. This often requires a quick response, but sometimes artificial slowness is also necessary. That means devices that deliberately respond slightly slower. Or algorithms that 'take a breath' before making adjustments. Compare it to the anti-lock braking system in a car: it brakes in a controlled manner so that your car remains controllable.'
Mathematics as the backbone of the energy grid
Solar parks and wind turbines are supplying more and more sustainable electricity and are an important pillar of the future sustainable energy system. But all these new sources have to be integrated into a grid that is not designed for them. On the other hand, there is also increasing electricity demand, for example, for electric transport and heat pumps. Hurink and his colleagues create mathematical models that analyse where the system will come under pressure from all these new developments and how you can manage this. For example, by not switching off all devices at the same millisecond in the event of a malfunction.
According to Hurink, mathematics is essential to keep control of the energy transition. But that requires cooperation between grid operators, policymakers and scientists from multiple disciplines. ‘The realisation that this is necessary often only comes when things go wrong,’ he says. ‘Sometimes a malfunction seems necessary to wake people up. But we are trying to prevent it from getting that far.’
