Understanding EV charging cost, solar vs grid
Why solar power isn't really free in a cost comparison
It's tempting to treat solar-charged miles as costing nothing, but that ignores the real money spent on the system itself. Levelized cost of energy, or LCOE, divides your system's total cost, including financing if applicable, by its expected lifetime production, giving a fair per-kWh cost to compare against grid rates. A well-sized owned system typically lands between $0.04 and $0.08 per kWh over 25 years, which is still far below most grid rates but not zero.
Solar offset percentage drives most of the savings
The gap between all-grid charging and solar-offset charging scales directly with how much of your charging actually comes from solar. A household at 50% solar offset sees roughly half the savings of one at 100% offset, all else equal, which is why array sizing and charging schedule both matter for maximizing this benefit.
The gasoline comparison puts EV savings in context
Even at full grid rates, EV charging typically costs meaningfully less per mile than gasoline in most US and Canadian markets, since electricity's energy-per-dollar is generally more favorable than gasoline's, especially at higher gas prices. Adding solar offset widens that gap further, which is part of why many EV owners with solar report per-mile costs a fraction of what a comparable gas vehicle would cost to run.
Net metering changes the picture slightly
This calculator assumes solar-offset charging draws directly from your system's real-time output, which is the simplest and most conservative way to model the comparison. If your utility uses net metering, where excess solar production earns credits used later, your actual savings may differ based on your specific compensation rate and billing structure, which the EV solar net metering interaction calculator addresses in more detail.
Building on this result
Multiply this annual savings figure across your expected system lifetime using the 10-year savings projection tool, or compare it against your added system cost with the EV solar payback calculator. To round this out, the solar savings calculator by utility rate covers the remaining piece.