A Real-Life Demonstration of Secondary Frequency Reserve Provision with Electric Water Heaters

Residential electric water heaters have the potential to significantly contribute to the balancing of the grid by providing frequency services. However, this entails a large-scale, challenging control problem subject to several uncertainties. In this paper, we perform the first real-life validation of secondary frequency reserve provision with a cluster of residential thermal loads in a near-commercial setting. We adopt an aggregate-and-dispatch control approach, which combines a scalable optimization step enabled by a reduced-order model with a real-time dispatch step. To handle the uncertainty related to service activation, we incorporate chance constraints in the optimization model and reformulate it as a robust problem. We validate the control approach under the assumption of perfect merit order knowledge in different stages, with a cluster of up to 600 electric water heaters, and show that this pool is able to effectively provide reserves, and that the integration of the chance constraints is beneficial for performance.