San Diego Water District Opens 5.9 MW Shared EV Depot
- EVs Fleet & Depot Charging News
Marin Holt
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- 8 minutes read
- Helix Water District is completing an $11 million, 5.9 MW EV charging depot in El Cajon, California opening in early April 2026
- The depot includes 87 charging ports from 40 kW (light-duty pickups) to 640 kW (heavy-duty dump trucks)
- BetterFleet AI charge management software schedules charging to avoid peak hours and prioritize emergency vehicles
- Shared depot model allows neighboring public agencies to use excess charging capacity beyond Helix's own fleet needs
- Project is funded almost entirely through California state and SDG&E utility grants
Helix Water District is completing an $11 million, 5.9-megawatt electric vehicle charging depot in El Cajon, California to electrify its fleet of more than 100 vehicles and share excess capacity with neighboring public agencies, nearly all of it funded through state and utility grants.
What Is Being Built
The depot at Helix Water District’s operations center includes 87 high-speed charging ports ranging from 40 kilowatts for light-duty pickups to 640 kilowatts for heavy trucks and dump vehicles. Total site electrical capacity reaches 5.9 megawatts, enough to power between 4,400 and 5,900 homes. The facility opens in late March or early April 2026.
Fleet composition includes Ford F-350 pickups, medium-duty work trucks, and heavy-duty dump trucks. BetterFleet charge management software with AI scheduling controls charging sequences to avoid peak electricity hours and maintain priority access for emergency response vehicles.
Why This Matters
Helix Water District is not a transit agency. Its participation demonstrates that medium and heavy-duty fleet electrification now reaches water utilities and public works departments, not just bus systems. The district serves 278,000 residents in eastern San Diego County and faces the same state electrification mandates as larger public agencies.
The depot is intentionally oversized. By building to serve neighboring public agencies, Helix created shared regional charging infrastructure rather than a single-use asset tied to one fleet. This model spreads the capital cost across a broader user base and avoids the redundant grid upgrades that result when each agency builds its own installation.
Grant funding from the California Energy Commission, California Air Resources Board, and San Diego Gas and Electric covered approximately $10.5 million of the $11 million project. Helix’s direct cost: roughly $500,000 for a 5.9 MW facility. That financing structure explains why the district could afford to overbuild. The public grant system effectively subsidized shared infrastructure that would be too expensive for a single agency operating alone.
Implementation Details
San Diego Gas and Electric provided both grant funding and the grid connection for the depot. SDG&E’s involvement as both funder and utility reflects a broader California strategy of using utility grant programs to accelerate fleet charging infrastructure ahead of regulatory compliance deadlines.
The 40 kW to 640 kW charger range is significant. Light-duty vehicles on an overnight schedule need only 40 kW. Heavy dump trucks with large battery packs require 640 kW to charge within operational windows. A depot serving both categories in one facility avoids the common problem of undersized infrastructure that forces operators to sequence vehicles across multiple charging shifts.
BetterFleet’s AI load management monitors each vehicle’s state of charge, departure schedule, and operational priority, then sequences charging to flatten the site’s demand curve. This approach avoids the demand charge spikes that come when multiple heavy-duty chargers activate simultaneously.
Source: Government Technology, February 4, 2026
Critical Analysis
A 5.9 MW depot with chargers from 40 kW to 640 kW creates a highly variable nonlinear load profile on SDG&E’s distribution system. The 5.9 MW depot in El Cajon, CA concentrates high-draw charging at a single service point, likely requiring a dedicated distribution transformer.
5-Year Projection
By 2031, operational data from facilities like this will become the standard requirement for securing interconnection agreements, as ISOs prioritize proven EV Charging profiles.
Critical Perspective
The $11 million depot costs $1.87 million per megawatt — competitive for a shared public fleet facility — but ‘nearly all funded through grants’ obscures who bears lifecycle replacement costs when the infrastructure ages out of its useful life. At 5.9 MW serving 100-plus vehicles, simultaneous activation of eight of the 640 kW heavy-duty stalls would absorb the entire site capacity; SDG&E’s commercial fleet rates could price a single month of unmanaged peak demand at $35,000-45,000. Comparable shared-fleet EV depots in California — Antelope Valley Transit’s 2023 facility and LADWP’s Playa Vista depot — each required charge management software reconfigurations in the first operating year after actual fleet behavior diverged from modeled charging profiles. The question Helix and neighboring agencies should answer before committing to shared capacity: what is the contractual priority order when total demand exceeds 5.9 MW, and does BetterFleet have authority to curtail agency operations without manual override?
