EVWired

09 · Solar charging

Estimate the value of solar EV charging

Estimate how much annual driving could be supported by surplus solar energy and the grid electricity spend that energy might avoid. Start with surplus after household use, not total panel generation.

Your inputs

Get your result

Use your own figures or load the worked example below. All calculations stay in this browser.

kWh / dayDaily surplus remaining after household consumption.
days / yearDays per year when that surplus is available.
%Share of surplus available while the car can charge.
km / yearUsed to cap solar charging at annual driving demand.
kWh / 100 kmVehicle battery consumption; losses are not modeled.
per kWhGrid price avoided per kWh; export income is excluded.
Display label only; all prices must use the same currency.
Add your surplus solar energy and local electricity rate.

The estimate assumes solar energy can be used when the vehicle is connected and does not include equipment or export-credit costs.

How to use this tool

  1. Enter daily surplus, the number of days it is available and the share you can direct to the connected car.
  2. Add annual driving distance, vehicle consumption and grid electricity price.
  3. Calculate solar use, which is capped at annual vehicle demand, and compare the avoided spend with any lost export credit.

Worked example

8 kWh of daily surplus for 250 days

Surplus solar energy
8 kWh / day
Days available per year
250 days / year
Share directed to the car
70 %
Annual driving distance
15000 km / year
Vehicle consumption
18 kWh / 100 km
Grid electricity price
0.2 per kWh
Currency display
US dollar ($)

Expected result 1,400 kWh solar used · about 7,778 km · $280/year grid spend avoided

8 × 250 × 70% = 1,400 kWh. Demand is 2,700 kWh, so all the modeled solar can be used. 1,400 ÷ 18 × 100 = 7,777.8 km; 1,400 × $0.20 = $280.

Transparent estimates

How to read this result

Avoided grid spend is not net profit or a solar payback estimate. Timing, charging losses, export compensation, battery storage and equipment costs can change the economics.

How it is calculated

  • Solar energy available to the car = daily surplus × available days × selected share.
  • Solar charging is capped at the vehicle's estimated annual energy demand; avoided spend = solar energy used × grid price.

Assumptions

  • Entered surplus is energy remaining after household use, and the selected share is available while the car can charge.

What this estimate cannot tell you

  • Seasonal mismatch, export compensation, charging losses, and system costs are not modeled.
← Back to all 12 tools