Scheduling and dimensioning of heterogeneous energy stores, with applications to future GB storage needs

Future ``net-zero'' electricity systems in which all or most generation is renewable may require very high volumes of storage, provided jointly by a number of heterogeneous technologies, in order to manage the associated variability in the generation-demand balance. We consider the problems of scheduling and dimensioning such storage. We develop a value-function based approach to optimal scheduling, and show that, to a good approximation, the problem to be solved at each successive point in time reduces to a linear programme with a particularly simple solution. We show that approximately optimal scheduling may be achieved without the need for a running forecast of the future generation-demand balance. We examine the applicability of the above theory to future GB storage needs, and discuss how it may be used to enable the most economic dimensioning of such storage, with possible savings of tens of billions of pounds, relative to the use of a single technology.Comment: Much simpler proofs, more illustrative examples, and other improvements. 24 pages, 7 figure