For the seventeenth time, the Swiss Federal Office of Energy has awarded Switzerland’s Watt d’Or energy prize – and ETH Zurich is one of the winners. ETH received the award in the Energy Technologies category in collaboration with AEW Energie AG. The Watt d’Or has been honouring pioneering projects and achievements in the energy sector since 2007.
ETH researchers Lukas Ortmann and Saverio Bolognani from the group led by Florian Dörfler, Professor at the ETH Automatic Control Laboratory, have been awarded the Watt d’Or for developing an algorithm, together with associated online feedback optimisation software, that can be used to solve an optimisation problem in the electricity grid. Specifically, they implemented their algorithm in the real-world environment of the AEW Energie electricity grid in a way that meant photovoltaic systems not only supply renewable electricity, but at the same time help to optimise reactive power.
Optimised, faultless grid operation thanks to real-time data
The ETH researchers’ collaboration with AEW Energie came about through the National Centre of Competence in Research “Dependable, ubiquitous automation” (NCCR Automation). Ortmann, now Professor of Control Engineering at the Eastern Switzerland University of Applied Sciences in Rapperswil, reports that they conducted a pilot project to test their optimisation software on an AEW Energie solar plant. Real-time information from the software is used to control the plant’s reactive power output in an attempt to conform as closely as possible to the reactive power in the grid, for instance to quickly reduce excessively high voltages.
Reactive power is a flow of electrical energy that consumers don’t use. In an alternating-current grid, it can be used to manage the voltage. The electricity grid requires reactive power for safe operation. Inverters convert direct current from a generator such as a photovoltaic system into alternating current for the grid. Thanks to the ETH software, the inverters now produce voltage-reducing or voltage-increasing reactive power, which is used to optimise the reactive power available in the grid.
What makes the ETH algorithm innovative and useful is that it is based on real-time data from the AEW electricity grid, so it can adjust the reactive power to the prevailing situation in a way that optimises the local flow of reactive power. The algorithm learns from real-time readings of voltage and reactive power how to guide the grid into its optimum operating state.