Frequency support using slower domestic resources and service stacking

This paper demonstrates that, even today, domestic batteries and electric vehicles (EVs) can fulfil all frequency containment requirements in the Nordic countries. Revenue from the provision of such primary frequency reserves (FCR-D) in Sweden is presented for the period 2002–2024. The aggregation of fast and slow resources into a virtual power plant is proposed. A novel approach for activating slower resources based on the Rate of Change of Frequency (RoCoF) is introduced, wherein faster resources compensate for any premature or excessive activation. The frequency quality in the Nordic synchronous area is analysed in depth. The proposed method is shown to reduce the activation of slower resources by a factor of 5,000, the duration of activation by a factor of 400, and the energy delivered in their frequency response by a factor of 80. It is argued that aggregating slower resources and enabling service stacking could increase market liquidity, ultimately reducing costs for end users. As EVs and batteries have other primary functions, a solution for service stacking is presented that enables resources to charge or discharge while simultaneously participating in the frequency containment reserve market.