Analysis of energy- and SoC-neutral contracts for frequency regulation with energy storage

We analyze two contractual frameworks for regulation services with battery-based energy storage: the SoC- and energy-neutral contracts. Vis-a-vis the existing contractual framework, the new contracts constrain the operator to generate only SoC- and energy-neutral regulation signals within a contract duration. For both contracts, we propose algorithms to maximize the battery operator´s reward during a single contract, and derive analytical expressions to quantify the reward over multiple contracts. Numerical results using Lead-Acid and Lithium-ion batteries provide several engineering insights.