Is an EV Time-of-Use Plan Worth the Monthly Fee?

Check which electricity use the plan covers

PG&E’s EV2-A plan is an example of an EV plan that applies to whole-home usage, so a charging-only calculation can miss part of the cost.

Start with your utility’s current plan description. Determine whether the offer applies to your existing household meter, a separate EV meter, or a charging service with different conditions. An EV label does not establish the billing arrangement.

Confirm the service area, eligibility, time periods, seasons, and fixed charges. A fixed charge may be quoted daily rather than monthly; convert it using the billing period you are comparing. If the arrangement requires separate equipment or metering, keep that upfront cost outside the monthly electricity comparison and evaluate it separately.

Use the official utility documents linked from its website. Do not rely on a rate shown in an old advertisement or assume your neighbor has the same tariff.

Compare two complete bills at the same usage

For 2 plans, hold household demand and charging demand constant before comparing energy and fixed charges.

Split non-EV usage into the proposed plan’s time periods. Then add EV charging in the hours when it would actually occur. If charging moves to cheaper hours, state that behavior change explicitly.

The Time-of-Use Calculator supports a flat-rate comparison against a peak/off-peak model with fixed charges. It is suitable only when those assumptions describe the comparison. It does not fully model every tariff, including plans with three time periods, demand charges, tiers, or complex credits.

Use the EV Charging Calculator to estimate charging energy cost separately. Then ensure that charging energy is included once, rather than added to a household total that already contains it.

Include the cost of household peak usage

In the hypothetical example below, household energy costs rise by $15 per month under the proposed plan before the additional $10 fixed charge.

All rates, charges, and usage figures here are invented for a worked example. Neither column describes an actual utility product.

Assume 600 kWh of non-EV household use: 300 kWh in the proposed peak period and 300 kWh off-peak. Charging takes place entirely off-peak.

At 300 charging kWh, the current plan costs $130 + 300 × $0.20 = $190. The proposed plan costs $155 + 300 × $0.15 = $200. Cheaper charging is not enough to offset the other differences in that scenario.

Taxes and other adjustments are excluded, and the modeled rates are assumed to include the variable charges being compared. If supply and delivery vary independently on your tariff, include both consistently.

Calculate the charging break even point

For this 2-rate example, the additional $25 monthly cost requires 500 off-peak charging kWh at a $0.05 saving per kWh to reach break-even.

The formula is:

Break-even charging kWh = (extra fixed cost + change in non-EV cost) ÷ saving per charging kWh.

Here, ($10 + $15) ÷ ($0.20 − $0.15) = 500 kWh.

Negative savings mean the proposed plan costs more. If non-EV costs already fall enough to cover the fee, no positive charging threshold is required under this model. If the saving per charging kWh is zero or negative, this division does not provide a useful positive threshold; compare total costs directly.

For charging across multiple periods, use the energy in each period and its applicable rate. A single off-peak price would misrepresent that schedule.

Use billed charging energy and check the full year

For an illustrative 90% charging efficiency, 450 kWh delivered to a battery requires 500 kWh from the wall.

Calculate wall energy as battery energy divided by efficiency: 450 ÷ 0.90 = 500. The 90% value is an assumption, not a universal efficiency estimate. If a meter or charging record already reports energy drawn from the wall, do not add losses again.

Repeat the comparison for different seasonal tariffs and household patterns. One favorable month is not a complete annual comparison. A summer increase in household peak use can change the result even if EV driving stays similar.

The state rate table is useful context, but EIA averages cannot replace your utility’s peak and off-peak tariff. Use your own rates and retain the tariff’s effective date with the calculation.

Frequently asked questions

These 4 questions help check whether an EV plan comparison is complete.

Is the lowest overnight price the cheapest plan

Not necessarily. Compare fixed charges and all affected household usage as well as the charging price.

Can I use miles driven instead of charging kWh

You need a supported conversion from miles to electricity consumption and must know whether that figure already includes charging losses. Direct wall-energy records avoid that extra assumption.

What if I cannot move all charging off peak

Assign the remaining energy to its actual charging periods. Do not count it at the off-peak rate merely because the plan offers one.

Does monthly savings mean the installation pays for itself

No. A charger, meter, or other installation cost needs a separate payback calculation using the relevant savings and upfront costs.