Understanding generator-charged EV cost
Why generator electricity costs so much more per kWh
Small portable and standby generators convert fuel to electricity at a fraction of the efficiency of utility-scale power generation, losing much of the fuel's energy content as heat rather than usable electrical output. Combined with the fact that liquid or gaseous fuel typically costs more per unit of delivered energy than grid electricity to begin with, generator-produced power routinely runs several times the cost of grid power on a per-kWh basis.
Putting the premium in perspective
For a typical daily charging session, the dollar difference between generator and grid charging might only amount to a few dollars, which matters little for a rare, short outage. The calculation becomes more meaningful for regions with frequent or extended outages, tracked in EIA electricity reliability data, where repeated generator charging sessions accumulate into a real annual cost worth comparing against alternative backup approaches.
Generator backup solves a different problem than battery backup
A generator provides backup power for as long as fuel supply lasts, which can be extended indefinitely with more fuel, while a battery is limited to its stored capacity but produces no ongoing fuel cost once charged. These are genuinely different tradeoffs, upfront cost and maintenance for a generator versus battery capacity cost and a hard capacity limit, and the right choice depends heavily on typical outage duration and frequency in your area.
Charging priority matters during a real outage
During an actual outage, most households prioritize essential home circuits over EV charging when running a generator, given a portable generator's limited output capacity. If EV charging is a priority during outages specifically, sizing the generator to handle both essential home loads and charging simultaneously is worth planning for in advance rather than discovering the shortfall during an actual outage.
What this result means for your next step
If the generator premium looks worth avoiding, compare it against the cost of adding battery backup capacity using the solar battery triple sizing calculator, or consider whether V2H equipment could provide backup power from the EV itself using the V2H payback calculator. Home solar charging only wins if it beats the grid price. The levelized cost of energy calculator in our Savings & Payback section can help you compare the two over the life of the system.