Why a small fleet can receive a large charging electricity bill

Start with the actual utility account

A fleet discussion about overnight energy needs and a separate DC charging discussion about low utilization raise different operating problems. Neither establishes a small depot's local tariff or bill. The billing question here is an editorial extension: what does the site's own rate charge for energy, simultaneous power, and a briefly exceeded limit? Start with the account and interval readings, not another operator's reported cost.

Source: Best overnight charging setup for small fleet 6-8 EVs · Looking for tips for increasing utilization at my DCFC station

Separate energy charges from billed power

An energy charge is tied to kilowatt-hours consumed. A demand charge, where applicable, is tied to measured power during the tariff's defined interval and billing rules. Other rates may use subscription capacity or different structures. DOE advises involving the utility early in infrastructure planning. Do not assume that a residential off-peak rate applies to a business depot or that charging after dark automatically avoids all demand-related costs. The active tariff and account eligibility control the calculation.

Source: Alternative Fuels Data Center: Procurement and Installation for Electric Vehicle Charging Infrastructure

PG&E BEV uses a subscription, not a conventional demand charge

PG&E's optional Business Electric Vehicle tariff offers BEV-1 and BEV-2 for qualifying commercial EV usage metered separately from non-EV use. It replaces conventional demand and customer charges with a monthly subscribed power allocation, alongside time-of-use energy charges. BEV-1 uses 10 kW blocks and BEV-2 uses 50 kW blocks. Eligibility and the metering arrangement need confirmation for the account.

Outside a qualifying grace period, exceeding the subscription triggers an overage based on the month's maximum 15-minute average demand above the allocation. The March 1, 2026 rate sheet lists the overage per kW at twice the corresponding subscription per-kW equivalent. That is a charge on excess kW, not a doubling of the whole bill. Model subscription blocks, overage exposure, and energy timing separately; refresh the tariff before making a financial commitment.

Source: PG&E Electric Schedule BEV: Business Electric Vehicles

Illustrative scenario: equal energy, different peak

Illustrative scenario: a fleet needs 160 kWh overnight. Delivering that energy at an average of 20 kW for eight hours has a different demand profile from delivering it at 80 kW for two hours. The energy quantity is equal in this simplified example; the site's measured peak may not be. If an existing refrigeration load already peaks at the same time, simultaneous vehicle charging can create an even higher combined demand. Conversely, a separate meter could introduce fixed charges that offset part of the expected savings.

Model the bill one component at a time

Request an interval-data simulation with the fleet added to existing building load. Model a normal week, a high-mileage week, and an emergency override that starts every available charger. Include the demand interval, seasonal rate changes, minimum charges, any applicable ratchet, and the actual charging losses assumed. Ask the analyst to show the bill components instead of one blended cents-per-kWh estimate. A blended number can conceal a fixed cost that remains even when fewer vehicles use the depot.

Keep cost overrides below the electrical limit

There are two distinct controls to consider: the maximum permitted electrical draw and the operating target chosen to manage cost. They should not be confused. A dispatcher may need a temporary cost override to rescue a late departure, but must never be able to override the installation's protective limit. Define who can authorize the operating override and what alert it creates. If the fleet routinely overrides the economic target, the energy schedule or tariff assumption is probably unrealistic.

Compare two charging schedules against the same building load

For a simplified comparison, assume the building draws 30 kW throughout a particular interval. Adding 20 kW of charging makes the combined draw 50 kW; adding 80 kW makes it 110 kW. That arithmetic explains why equal overnight energy can produce different site peaks. It is not a utility bill estimate: the actual meter interval, time-of-use periods, and applicable tariff determine whether and how either condition is billed. Use interval data and the current account's rules before attaching a dollar amount to the difference.

Also test a day when the building peak happens before the vans return. Charging that stays below the already established billing peak may have a different marginal cost from charging that creates a new one. If the tariff includes seasonal windows or a demand ratchet, those features can change the conclusion again. The analyst should explain which condition controls the model instead of assuming that every kilowatt of charging produces the same additional charge. This is one reason a neighboring business's reported charging cost is a poor substitute for the property's own account analysis.

Set an operational review around exceptions. When a dispatcher authorizes faster recovery charging, record the reason, time, affected vehicles, and resulting power profile. Repeated exceptions are evidence that the selected economic cap may not fit the work schedule. A single unusually expensive month can also reveal a control reset or an unexpected building load. Keep those possibilities separate from equipment efficiency: higher consumption for the same routes, a higher tariff price, and a higher billed peak are three distinct findings. A useful first-bill review shows which one occurred and assigns a corresponding action.

Preserve the model for a first-bill review

At handoff, preserve the tariff version, modeled arrival schedule, baseline interval data, control settings, and first-bill review date. Compare the first complete bills with the model and investigate deviations by component: energy, demand, fixed fees, and third-party network charges. A higher bill does not automatically mean the equipment is inefficient. It may mean vehicles returned later, the tariff changed, or a building load coincided with charging. Those causes call for different corrections.

Put it into practice

A decision table to keep handy