Short answer: A generator’s yearly fuel cost is roughly hours per day × average load (kW) × litres per kWh × fuel price × 365. At 12 hours a day, 40 kW average load, 0.3 L/kWh and USD 1.20 per litre, that is about USD 63,000 a year. Solar and storage reduce the hours the generator runs and let it run at a more efficient load.
Getting a better number
| Input | Best source |
|---|---|
| Running hours | Generator hour meter over a month |
| Average load | Generator controller log or a clamp meter survey |
| Litres per kWh | Fuel deliveries ÷ kWh produced |
| Fuel price | Delivered cost, including transport and losses |
Next step
Send us a month of fuel deliveries and hour-meter readings with your site location. We return a hybrid design with solar, battery and generator dispatch, and the estimated fuel saving.
