Residential storage to improve system resilience: Technical design and cost estimation

摘要

Facing exceptional events (storms in the USA, the great earthquake in East Japan...), several countries have launched efforts to improve the resilience of the electrical system, ie its ability to limit outages in case of these incidents. We clarify what improving resilience means, and show how it differs from reliability. We study how technically and economically, distributed storage could improve the electric system resilience. We explain how a distributed storage device could contribute to resilience in case of exceptional events: in an emergency operation, it could feed a local grid, possibly carbon-free, which would then feed the priority uses of residential customers. The study does not address the economic profitability of improving the resilience of an electrical system. But knowing how storage could improve the resilience, we study the costs of such a solution and propose a first quantification of these costs. To do that, we characterize the typical client and define the emergency local grid (for instance, a building of 100 residential clients); then we choose and quantify priority uses, with reference to international experience. The priority needs are estimated both in power and energy, in mean value and in standard deviation. We review the different types of exceptional incidents, their consequences in outage duration and if the exceptional event is partially predictable. In the important case of a storm, we can estimate the cost of the solution of resilience by distributed storage. First, if the solution is devoted to improve resilience: 128 €/year/customer in a typical case. Secondly, the approach considers that the cost of storage can be partially compensated for if storage contributes to other services in normal situation. Then, at least marginally, the cost could be reduced by 52%.