Santa Barbara Zero-Emission Resilient Transportation Blueprint: A Microgrid Design for Santa Barbara Metropolitan Transit District
Publication Number
CEC-600-2025-001
Updated
January 03, 2025
Publication Year
2025
Publication Division
Transportation Energy (600)
Program
Clean Transportation Program
Author(s)
Bryan Lee, Aditya Kushwah, Mike Hynes, Brian Ballschmidt
Abstract
Santa Barbara Metropolitan Transit District is an early adopter of electric buses and has a Board of Directors goal to convert its fleet to 100% zero-emission by 2030, and a State of California mandate to do so by 2040. However, electric buses are dependent on the utility grid because they use electricity directly as a fuel. If there is a lengthy grid outage, the buses cannot charge, which effectively disables the fleet. This would be a major problem for Santa Barbara Metropolitan Transit District, because the Santa Barbara area is vulnerable to grid outages due to its reliance on a single set of transmission lines that traverse terrain that has high natural disaster risk. To mitigate this threat, Santa Barbara Metropolitan Transit District aims to deploy a microgrid. A microgrid is a local grid that uses DERs including energy storage assets to provide power to a specific campus or facility. A key feature of microgrids is their ability to disconnect from the grid and generate their own power. A switch at the point of connection with the utility grid and a controller that decides when to connect and disconnect from the main grid manages this feature. Essentially, microgrids must be able to function as an island, operating even when isolated from outside power sources. This is why solar power systems and standalone generators, by themselves, are not microgrids. Microgrids can play a key role in electric vehicle fleet resiliency by supplying power to charging assets during grid power outages. This project investigated the techno-economic feasibility of a microgrid and other resiliency measures to support Santa Barbara Metropolitan Transit District’s electric bus deployments. This study found that microgrids are technologically and economically feasible.