Generator fuel consumption rates vary significantly based on size and load. For example, a small diesel generator (8 kW / 10 kVA) consumes approximately 1 litre per hour at quarter or half load, 2 litres per hour at three-quarter load, and 3 litres per hour at full load. Larger units (such as 1000 kW / 1250 kVA) may consume up to 259 litres per hour at full load[1].
Typical fuel consumption brackets are as follows[3]:
- Small generators (5–10 kW): 1–2 litres per hour
- Medium generators (10–50 kW): 2–6 litres per hour
- Large generators (50–200 kW): 6–20 litres per hour
- Industrial generators (200+ kW): Over 20 litres per hour
Fuel consumption is also proportional to the generator load. At 50% load, a generator will use less fuel than at 100% load. Precise consumption can also be calculated per kWh; for diesel sets, the rate is typically 0.2–0.26 kg/kWh, equivalent to about 0.24–0.3 litres of diesel per kWh generated[5].
For direct reference, here are some approximate per hour fuel requirements (diesel, at full load)[1]:
- 8 kW / 10 kVA: 3 litres
- 40 kW / 50 kVA: 12 litres
- 160 kW / 200 kVA: 40 litres
- 400 kW / 500 kVA: 106 litres
- 800 kW / 1000 kVA: 220 litres
- 1000 kW / 1250 kVA: 259 litres
Actual fuel consumption depends on factors such as load, maintenance, and generator efficiency. Brands known for optimizing fuel efficiency include Caterpillar, Cummins, and Perkins[6].