Abstract

Co-authors: Michael Evans (Imperial College London), David Angeli (Imperial College London). We consider the problem of dispatching a fleet of heterogeneous batteries (i.e. energy-constrained generators) to prevent or minimise power shortage scenarios. In the general case on which nothing is known about future power requirements, three significant results are derived. First, a greedy policy exists that uniquely maximises the time until the fleet is first unable to supply demand. This policy implicitly establishes a `feasible set’ of power requests that can be satisfied by the fleet. Second, an analytical transformation is presented that expresses this feasible set in a graphical form instead of a procedural form (i.e. by invoking the policy). The graphical representation also provides a measure of the flexibility penalty due to heterogeneity. Third, it is shown that the policy can be extended to handle scenarios with unavoidable power shortages, in which case it minimises the energy not supplied. The fact that the greedy policy results in best-case security-of- supply performance suggests it is suitable to be used as a reference policy for battery dispatch within system adequacy studies. We present a discrete time algorithm that is tailored for this use case and show results for a Great Britain case study.