How to Decrease the Consumption of Diesel Generator

Efficiency is always a goal, especially when using a fuel that requires storage in sufficient quantities.

Fuel use directly equates to power consumption. The more electrical power used, the more fuel the generator will use to produce it. For example, consider the fuel consumption of this 50 kilowatt diesel generator operating at 50%, 75%, and 100% of rated load.

50% load (25 kilowatts) = 2.15 gallons (8.14 liters) per hour.

75% load (37.5 kilowatts) = 3.06 gallons (11.58 liters) per hour.

100% load (50 kilowatts) = 3.98 gallons (15.07 liters) per hour.

Clearly, increasing power consumption uses more fuel.

What may not be so obvious is that at the higher load, less fuel is consumed per kilowatt than at the lower load.

0.0860 gallons an hour per kilowatt at 50% load.

0.0816 gallons an hour per kilowatt at 75% load.

0.0796 gallons an hour per kilowatt at 100% load.

This particular generator operates most efficiently under 100% rated load of 50 kilowatts.

Beyond the obvious solution of proper maintenance and condition of the generator’s diesel motor, we can draw two conclusions for reducing power consumption:

Eliminate unnecessary loads from the total. If you can operate at 50% rated load rather than 75%, you will save nearly 1 gallon per hour in fuel on this particular generator.

When selecting a generator, choose one that operates the most efficiently at the most commonly needed load. In other words, if the need is for 75 kilowatts 80% of the day, and 50 kilowatts for 15% of the day, and 90 kilowatts for 5% of the day, choose a generator that can supply the highest load needed with some margin, say 100 kilowatts, but has the greatest efficiency at the most common load of 75 kilowatts.

Remember that it uses fuel just to start and run the generator before any load is introduced. If power use is intermittent, a unit that can idle at lower rpm while not under load reduces fuel consumption.