Towards a coupled energy and reserve modeling for power system balancing

With the ongoing changes in the Nordic power system, specifically the increased share of weather-dependent resources and flexible technologies, alongside European harmonisation of reserve markets, challenges related to the market design of energy and reserve provision arise. Since the same physical assets provide both energy and reserves for real-time balancing, decisions about how to allocate capacity across energy and reserve services are inherently coupled. This raises the question of whether the current market design allocates resources to the services that best fulfil the system needs. To explore this, a framework for modelling this interdependence is proposed. Furthermore, two studies are presented to highlight some aspects of the interdependence; one related to the impact of market closure nearer delivery time on hydropower reserve allocation, and one on mFRR bidding strategies for battery energy storage and their dependence on reserve needs.