Methodology for combined Integration of electric vehicles and distributed resources into the electric grid

Abstract

Plug-in electric vehicles and distributed generation are expected to appear in growing numbers over the next few decades. Large scale unregulated penetration of plug-in electric vehicles and distributed generation can each have detrimental impact on the existing electric grid infrastructure. However, appropriate pairing of the two technologies along with some storage could mitigate their individual negative impacts. This thesis develops a methodology and an optimization tool for the design of grid connected electric vehicle chargers that integrate distributed generation and storage into a single system. The optimization tool is based on a linear programming approach that identifies designs with the minimum system lifecycle cost. The thesis also develops the component and system cost models needed for this optimization. The tool can handle single and multiple charger systems with centralized or distributed generation and storage. To verify the tool's accuracy, a search-based optimization technique that works for single chargers with centralized generation and storage is also developed and used to validate the tool. To demonstrate the usefulness of the optimization tool, it is used to design optimal architectures for a single-charger residential charging case and a multi-charger public charging case. It is shown that designs that draw the maximum available power from the grid have the lowest 20-year system lifecycle cost. When storage is needed because the grid cannot provide full charging power, optimal designs may or may not include solar PV based distributed generation depending on the location. For example, in locations with solar irradiation profiles like Los Angeles, CA, electric vehicle charger designs that include solar PV generation are optimal, while in locations like Eugene, OR, optimal designs do not include solar PV. It is also shown that with the available technology, wind turbines are not cost effective for use in residential chargers in locations with wind speeds similar to Los Angeles, CA and Boulder, CO. For the multicharger public charging case, designs with centralized storage and generation are optimal.