US school district to deploy solar-plus-storage microgrid for EV buses

Porterville Unified School District (PUSD) has partnered with commercial and industrial (C&I) solar developer ForeFront Power to construct an integrated solar, battery energy storage, islandable microgrid, and EV fleet charging system.

The project aims to tackle the district’s overlapping needs for localized grid resilience, operational expenditure reduction, and fleet electrification.

The physical footprint of the project features a 763 kW solar array mounted across existing shade structures in the district’s north and south parking lots. The solar assets are paired directly with a 408 kW/1,632 kWh (four-hour duration) lithium-ion battery energy storage system (BESS).

• Solar Array Capacity: 763 kW (Parking lot shade structures)
• Storage Capacity: 408 kW/1,632 kWh BESS
• EV Infrastructure: 35 DC fast charger ports
• Vehicle-to-Grid (V2G): Two bi-directional ports
• Utility Interconnection: Southern California Edison

A dedicated microgrid controller manages the system, enabling the school district to island from the local SCE distribution grid during outages or peak demand periods. When islanded, the facility draws power directly from the co-located solar canopies and BESS assets, ensuring continuous operation of critical district infrastructure. During standard grid-tied operations, the intelligent controller manages battery discharge cycles to shave peak demand and minimize demand charges.

The on-site generation and storage infrastructure will power 35 DC fast charger ports dedicated to PUSD’s expanding fleet of electric school buses. To mitigate the high coincidental peak loads associated with simultaneous fleet charging, the district is deploying The Mobility House’s smart charge management platform, ChargePilot. The software dynamically balances charging loads by drawing from the on-site solar and storage assets in tandem with grid supply, optimized based on real-time utility pricing structures.

Notably, two of the 35 fast chargers will feature bi-directional capabilities, establishing a vehicle-to-grid (V2G) framework. This configuration allows the electric buses to operate as mobile energy storage assets, capable of discharging power back into the local grid or the school’s facilities during high-tariff periods under California’s shifting regulatory landscape. 

The infrastructure development is funded in part through a grant from the US Environmental Protection Agency’s (EPA) Clean School Bus Program. Clean transportation non-profit CALSTART assisted PUSD in navigating the federal application and compliance process for the grant.

By leveraging federal funding alongside commercial solar-plus-storage structures, the project offers a repeatable framework for Central Valley school districts attempting to meet California’s zero-emission fleet mandates while insulating themselves from escalating demand charges.

From pv magazine USA