Methods of operating an energy storage system

An apparatus for controlling operation of an energy storage system, the energy storage system being arranged to supply power to a power grid at a time tb over a predetermined operation time window, the apparatus comprising:

• communication circuitry
• at least one processor;
• and
• a non-transitory computer-readable medium having stored thereon software instructions that, when executed by the at least one processor, cause the apparatus to:
• determine a current state of charge, SoC, of the energy storage system at a time t0;
• estimate a total energy usage by the energy storage system between the time t0 and the time tb;
• determine a forecast SoC of the energy storage system at the time tb based on the current SoC and the estimated total energy usage;
• input the forecast SoC, at least one operation constraint and one or more system parameters to an optimisation algorithm, the at least one operation constraint being an operation condition to be met by the energy storage system during the predetermined operation time window, and the one or more system parameters being parameters specific to the energy storage system;
• determine a plurality of power values each corresponding to a time step during the predetermined operation time window using the optimisation algorithm, wherein each power value is decomposed into an integer component and a float component;
• and
• select one or more power values from the plurality of power values with a zero float component to form an operation baseline at which the energy storage system is to be operated during the predetermined operation time window.