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Electric Bus Energy Cost Estimator

This estimator calculates the electricity cost of operating an electric bus over a selected distance. It uses energy consumption per mile, charging losses, electricity price, demand or session charges, and optional maintenance savings to show both gross charging cost and an adjusted operating cost.

Transit agencies can use the outputs to compare service blocks, depots, tariffs, or bus assignments on a consistent per-mile basis. The result excludes vehicle financing, driver labor, insurance, taxes, and infrastructure capital unless those amounts are entered as additional charging charges.

Calculator inputs

mi
kWh/mi
%
$/kWh
$
$/mi
Result
—
Adjusted operating energy cost
Gross charging cost—
Adjusted cost per mile—
Grid energy purchased—
Maintenance savings—

1. Enter the operating distance
Use the same period for distance, fees, and any savings assumptions.

2. Add measured energy use
Use route-level kWh per mile when possible.

3. Include charging losses
Enter the share of grid energy lost before it reaches the battery.

4. Set the electricity tariff
Use the blended energy price for the charging period.

5. Add non-energy charges
Include demand charges, session fees, or other directly attributable charging costs.

6. Apply optional savings
Enter avoided maintenance cost per mile only when you want an adjusted comparison.

Battery energy = Distance × Energy use per mile

Grid energy = Battery energy ÷ (1 − Charging loss)

Gross charging cost = Grid energy × Electricity price + Demand/session charges

Adjusted cost = Gross charging cost − Distance × Maintenance savings per mile

What the result means

The main result shows electricity and charging charges after subtracting the entered maintenance savings.

A negative adjusted cost means the entered savings exceed charging cost; it does not represent total fleet profitability.

Given: 6,000 miles, 2.2 kWh/mi, 8% charging loss, $0.16/kWh, $450 in charges, and $0.06/mi maintenance savings.

Calculation: Battery energy = 13,200 kWh. Grid energy = 13,200 ÷ 0.92 = 14,347.83 kWh. Gross cost = 14,347.83 × $0.16 + $450 = $2,745.65. Savings = 6,000 × $0.06 = $360.

Result: Adjusted cost is $2,385.65, or about $0.40 per mile.

Should demand charges be entered as a monthly or annual amount?

Enter charges for the same period as the distance figure. If distance is annual, use annual demand and session charges.

Why is grid energy higher than battery energy?

Conversion, cabling, thermal management, and battery losses require more energy from the meter than the battery stores.

Can I compare this result with diesel fuel cost?

Yes, but compare on the same mileage and include equivalent categories. A full comparison may also need fuel taxes, maintenance, emissions systems, and infrastructure costs.

What electricity price should a depot use?

Use a blended rate based on actual tariff energy charges for the charging window. Keep demand charges separate to avoid counting them twice.

Does the maintenance savings input cover all maintenance?

No. It is an optional per-mile offset chosen by the user and should be based on a documented comparison, not treated as a universal value.