As the school district pursues zero emissions, Sage’s feasibility plan finds the most cost-effective way to power its new electric school buses
Stockton, Calif., July 27, 2021 — Stockton Unified School District (SUSD) rolled out new electric school buses for a student field trip to the Port of Stockton. Sage Energy Consulting’s recommended renewable energy strategy to support fleet electrification efforts will save the District nearly $600,000 over the next 20 years.
Sage Energy Consulting worked with the Center for Transportation and the Environment (CTE), the Stockton Clean Mobility in Schools Program Manager, to evaluate the physical and financial viability of integrating solar PV and Battery Energy Storage System (BESS) with charging infrastructure for the new electric buses.
Specifically, Sage examined:
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Current and projected electrical consumption, to determine if the existing PV system has sufficient output and can be redirected to charge the new electric school bus fleet.
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The costs and benefits of utilizing existing PV or adding additional solar and battery energy storage.
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Approximate value of Low Carbon Fuel Standard (LCFS) credits generated by the District (through 2030) to help defray PG&E cost of electric school bus charging.
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Utilizing Renewable Energy Credits (RECs) generated by the District’s PV systems to boost the value of LCFS credits by ~18%.
“Our team found the optimal renewable energy strategy for the fleet electrification project, while recommending the use of RECs to maximize the savings generated through California’s Low-Carbon Fuel Standard program,” said Brent Johnson, Principal, Sage Energy Consulting. “As current policies sunset, new policies are enacted, and technology evolves, this plan will be reevaluated.”
Based on Sage’s evaluation, the financially optimal path for the District was to continue to power building loads from the existing PV system, and avoid any new paired PV or storage with electric school bus charging. This recommendation was driven by the PV system generating a lower value of energy on the EV service, due to the production aligning with low-cost electricity periods of the day when the school buses would typically charge. A standalone BESS would only produce negligible savings when installed in conjunction with solar PV to support electric school bus charging.
The renewable energy strategy recommendations made to the District reflect current tariffs, policies, and incentives. The energy landscape in California is rapidly changing and in order to account for future planning, Sage recommended that the District install additional spare conduits during charger installation to make solar and BESS installation in the future more cost-efficient.
“Stockton Unified School District continues to lead in their pursuit of ambitious zero-emission goals that also make sense for the District financially,” added Johnson. “When it comes to energy planning, it’s important to consider all your options and determine which option has the best cost-benefit ratio. In this instance, it turned out that employing the existing PV system to offset building loads is more financially advantageous than pairing PV and storage with the school bus charging. Getting energy from the grid to charge the new electric school buses makes the most financial sense in the short- to mid-term unless the District is able to secure a grant of ~$600,000 to install a dedicated new PV system to deliver 100% renewable electricity to the fleet.”
Featured Image courtesy of Stockton Unified School District
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