The value of energy storage for an industrial customer on a utility distribution network

Abstract

Energy crises experienced by the electricity utility in South Africa has a huge impact to the country’s functioning sectors particularly the industrial sector. Henceforth, adoption of renewable energy sources by these sectors is critical and is of paramount importance. The research in this dissertation is about a proposed hybrid energy storage system for an industrial customer on a utility distribution network. The hybrid energy storage system considered are the Battery Energy Storage System (BESS) and Fuel Cell (FC) connected in parallel to each other and inverted in Alternating Current (AC) using the bi-directional Power Conversion System (PCS). This research used two engineering software namely, Digsilent PowerFactory and Hybrid Optimisation Multiple Energy Resources (HOMER). The Digsilent PowerFactory was specifically used for the technical analysis of the network while the HOMER software was solely used for economic analysis of ESS to be incorporated into the distribution network. The study used the Digsilent functionality called Quasi-Dynamic Simulation Language (QDSL) to model the network. QDSL is a program used in the model definitions to give existing network models logic, which is dependent on the manner in which one requires the model to operate. The programmable logic enabled the user to define how the energy storage system operates, including setting limits and measurements that get calculated autonomously. Quasi-Dynamic Simulation was coded to determine when the BESS and FC should charge and discharge. QDS plots/graphs showing Peak Shaving of the load, improvement of the voltage magnitude, and reduced electrical losses were achieved. Furthermore, in this research project, another objective was to analyse economic feasibility of the energy storage system interconnected with utility distribution network using National Renewable Energy Laboratory (NREL) HOMER software. The optimisation results revealed the Net Present Cost (NPC) to be R36, 936, 360.00(US$2,234million), the Levelised Cost of Energy (LCOE) was R0.1055 (US$0.0064), and the Operating cost was R1, 789, 352.00 (US$108,233) respectively. The study found the energy storage system interconnection to be cost effective. A breakdown cost analyses of the configuration is presented in a Pie Chart format.