Abstract
Abstract This paper is concerned with assessing the contribution of grid-scale storage to generation capacity adequacy. Results are obtained for a utility-scale exemplar involving the Great Britain power system. All stores are assumed, for the purpose of capacity adequacy assessment, to be centrally controlled by the system operator, with the objective of minimising the Expected Energy Not Served over the peak demand season. The investigation is limited to stores that are sufficiently small such that discharge on one day does not restrict their ability to support adequacy on subsequent days. We argue that for such stores, the central control assumption does not imply loss of generality for the results. Since it may be the case that stores must take power export decisions without the benefit of complete information about the state of the system, a methodology is presented for calculating bounds on the value of such information for supporting generation adequacy. A greedy strategy is proven to be optimal for the case where decisions can be made immediately after a generation shortfall event has occurred, regardless of the decision maker’s risk aversion. The adequacy contribution of multiple stores is examined, and algorithms for coordinating their responses are presented.
Highlights
The flexibility offered by grid-scale electrical energy storage plays a crucial role in lowering the cost of power delivered by future low carbon networks, whilst maintaining their reliability [1,2,3,4]
This paper has presented a methodology for assessing the potential contribution of storage in supporting the capacity adequacy of a power system, based on a clearly stated probability model and operational strategy for the store
Results were presented for a specific exemplar based on the Great Britain (GB) system, for stores with energy capacities ranging from 200–10,000 MWh
Summary
The flexibility offered by grid-scale electrical energy storage plays a crucial role in lowering the cost of power delivered by future low carbon networks, whilst maintaining their reliability [1,2,3,4]. The cost savings associated with the presence of significant storage capacity in future systems include reductions in capital expenditure on generation, transmission and distribution infrastructure along with reduced operating costs [1]. While it is argued in [4] that many analyses focus on the high costs of storage without fully evaluating potential savings, it was suggested in [2] that these savings will be of the order of $109 to $1010/year for the GB system by 2030. The store is assumed to have constant power output capacity s and useable energy storage capacity e. In addition (as is currently the case in GB and possibly other systems) pumped storage plants may have a sufficiently high energy to power ratio that finite energy capacity does not restrict their contribution to capacity adequacy [14]
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