PRINCETONIAN ELECTRICITY: MANAGING AN ISOLATED MICROGRID

Abstract

Microgrids, distributed energy generation and storage systems, are radically changing the status quo in electricity generation. An isolated microgrid is one that is permanently disconnected from the larger power grid due to technical, economic or efficiency constraints. Isolated microgrids enable provision of electricity in remote areas that currently have no access to the electrical state grid. However, energy management of an isolated microgrid poses challenges of efficiency and reliability. This thesis adopts an approximate dynamic programming approach to mathematically model energy management of an isolated microgrid, using Princeton University’s microgrid as a case study. It simulates a hypothetical environment where Princeton University generates all of its own electricity using its existing resources and additional dispatchable generation and/or a battery. Adding dispatchable generation generally decreases demand shortage and percentage of outages. Increasing dispatchable generation also decreases the size of battery required for the microgrid. Due to the marginal increase in levelized cost of energy generation but far greater reliability benefits, it is always preferable to include both a battery and a dispatchable generator to the setup. The cost-preferred technology setup, with an additional 14MW in dispatchable generation and a 0.71MWh battery, has a net present cost in the range of $55milion to $85million and a levelized cost of approximately $70.3/MWh. This thesis illustrates that it is feasible to reliably operate Princeton University as an isolated microgrid given some additional dispatchable generation and a battery of storage capacity in the range of 330kWh to 880kWh.