Sustainable Reserve Power From Demand Response and Fluctuating Production—Two Danish Demonstrations

The Danish grid is moving from a system based on centralized fossil-fueled power plants to a system based on renewable energy where wind is a major energy source. This raises a number of challenges. A main challenge is that the centralized power plants currently are the main providers of reserve power. Alternative sources of flexibility are consequently needed as the conventional power plants are being replaced with fluctuating renewable energy sources. In this paper, we present results from two key demonstrations which illustrate that alternative sources of flexibility exist and that this flexibility can be utilized for reserve power. In the first demonstration, a portfolio of inhabited households heated with heat pumps are remotely monitored and controlled such that the aggregate consumption follows a power reference. This experiment is conducted over a full week where an hourly power reference is tracked while the comfort of the inhabitants is ensured. In the second demonstration, an operational wind power plant is regulated to provide a system-stabilizing response. This experiment is conduced over a 2-h period where the wind power plant follows a 5-min power reference. Together, the two demonstrations illustrate that both consumption and fluctuating production can contribute as sources of reserve power and a sustainable alternative to conventional fossil-fueled power plants in the future grid.