A central inventory of storage and other technologies to defer distribution upgrades-optimization and economics

We examine some alternatives available to postpone the upgrading of distribution facilities such as upgrading a transformer in a substation, or reconductoring a line. This concept of distributed utility installation examines alternative technologies from a central inventory to be wheeled into a substation, operated for a few months and moved to a different substation if conditions warrant. The economics of holding portable energy storage units to postpone transformer upgrades are examined for their optimum size, using the distribution system of a utility in a large metropolitan area as an example. The optimization method uses a dynamic program. This analysis is also applicable to other technologies such as flywheel energy storage, photo-voltaic generation, or fuel cells.