The networks

With this in mind, what are the main challenges facing electricity networks? They are twofold: at the local level, it's the integration of renewable sources of energy (unless they disappear completely). At the European level, it's the need to develop the global grid. Damien Ernst has focused his research on both of these issues.

Let's first examine the local problem. Previously, network managers faced a relatively simple situation: production followed consumption. Now, because of renewable energy sources that are often intermittent, the opposite is true: consumption must adapt to production. Photovoltaic panels produce most  of their power within 4 hours. To integrate them into an energy system, demand must be managed to encourage more consumption when electricity is more available, and vice versa. Progress in information technology has made this kind of management possible. "But that's not the main problem in Wallonia," explains Damien Ernst. “Before, large production units and several major industrial users were connected to a transmission network, as were distribution networks that provided energy to final consumers. Very few production units were directly connected to the distribution networks. All management was thus handled at the transmission network level, where all the decisions were taken (for example, the balance between production and consumption). At the distribution level, the work basically consisted in digging a trench, putting in a cable, and connecting everything. But now renewable energy sources are also connected to the distribution network (PV panels or wind turbines, for example). Management must therefore be more dynamic.” Paradoxically, the most frequent problem isn't a shortage of power, but rather the injection of too much power into the distribution networks, with creates problems of thermal limits and power surges. Thousands of PV panels are very hard to manage, as they are responsible for power surges in very sunny weather (up to 260 volts rather than the expected 220-230, and the more unused power that is injected into the network, the more the voltage increases!), which could potentially damage household appliances.

A global grid