Executive Summary:Charging an Electric Vehicle with home solar generates power at an effective levelized cost of $0.052 per kWh. Compare Level 2 48A home charging curves against utility Time-of-Use rates and DC fast chargers.
### The Convergence of Rooftop Solar and Electric Mobility
Electric vehicles (EVs) have fundamentally altered residential electrical load profiles. An average commuter driving 12,000 miles per year in an EV consuming 3.2 miles per kilowatt-hour ($312.5 \text{ Wh/mile}$) requires **3,750 kWh of additional annual electricity**.
Depending on your utility rate structure, this additional energy can either cost $1,500+ annually on tiered peak grid rates, or practically pennies when generated via an integrated rooftop photovoltaic system.
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### Levelized Cost Comparison: 12,000 Miles Annually
```
Annual Fueling Cost Comparison for 12,000 Miles (EV vs ICE vs Solar):
Gasoline (28 MPG @ $3.65/gal) : $1,564 / yr [========================]
Public DC Fast Charging ($0.48/kWh) : $1,800 / yr [===========================]
Utility Grid Peak TOU ($0.34/kWh) : $1,275 / yr [====================]
Utility Grid Off-Peak ($0.16/kWh) : $600 / yr [=========]
Home Rooftop Solar PV ($0.052/kWh) : $195 / yr [===]
```
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### Sizing the Dedicated Solar Array for EV Charging
To offset 3,750 kWh per year, the required PV DC nameplate capacity depends on your local **Peak Sun Hours (PSH)**:
$$\text{Array Capacity (kW DC)} = \frac{\text{Annual Energy Demand (kWh)}}{\text{365 Days} \times \text{Daily Peak Sun Hours} \times \text{System Derate Factor}}$$
Assuming:
- Annual Demand = $3,750 \text{ kWh}$
- Average Peak Sun Hours = $4.5 \text{ hours/day}$
- System Derate Factor (temperature losses, inverter efficiency, wiring) = $0.80$
$$\text{Array Capacity} = \frac{3750}{365 \times 4.5 \times 0.80} = 2.85 \text{ kW DC}$$
With modern **440W to 550W N-Type TOPCon panels**, this requires only **6 to 7 solar panels** to completely power an electric commuter vehicle for life.