How much fuel does a generator use?

how much fuel does my generator use

With the ever increasing energy and fuel costs these days, we are all looking to decrease our fuel consumption and also become more environmentally friendly.

The amount of fuel a generator will burn will depend on the generator size in kw, the type of fuel, the load or power being used and the efficiency of the engine.

So in this post we are going to discuss the various factors that determine how much fuel a generator will use.

The size of the generator will greatly affect how much fuel is burned as bigger generators need a bigger engine to power the full load. With bigger engines comes higher fuel consumption.

At Solent Power, we offer a large selection of generator sales and the different types of generator will require different fuels. Different fuels will burn at higher or lower rates. Natural gas generators will use more fuel than a diesel generator, but natural gas is at a lower cost than diesel.

Engine efficiency is also important, most generators with low power requirements and stable load will be fitted with a mechanical or hydraulic fuel governor, which controls the amount of fuel being delivered to the engine.

These types of fuel control systems are less efficient than electronic fuel control systems that can handle more power and vary the fuel delivery to the engine based various factor including the load.

Below is an example of a fuel consumption chart for diesel generators.

diesel fuel generator consumption chart

What fuel does a generator use?

Generators can be powered with various fuel sources such as diesel, natural gas and petrol.

There are other alternative fuels such as GTL (gas to liquid) and HVO (hydro-treated vegetable oil) that burn slightly cleaner and can reduce emissions. However, with the increasing fuel prices right now we want to reduce our costs and operating expenses.

Petrol generator fuel

Petrol is used for portable generators and inverter generators where the power requirement is low and the generator size kw only reaches approx 8 kw. Portable generators don’t generally use much fuel which means they only have a small tank and are perfect for outdoor activities that require power.

An inverter generator is the most efficient portable generator because its speed will vary based on the power output required. This means that is uses less fuel and benefits from not only being portable, but being able to power a range of different appliances and can be used in remote areas.

When generators get bigger than this, diesel is the preferred fuel.

Diesel generator fuel

Diesel fuel is the most common fuel for generator use due to its high torque delivery. This makes it suitable for standby generators to be used in a power outage to make sure enough power is provided for all site appliances.

As an estimate of how much fuel does a diesel generator use, you can multiply the size of the standby generator in kVA by 0.25.

This provides a litres per hour that diesel generators will burn on full load. This is only a rule of thumb and this number can vary due to various factors such as temperature or quality of fuel.

To make your diesel generator more fuel efficient you should prepare your diesel generator for the winter months and know what type of oil to use.

Gas generator fuel

Natural gas is an efficient way of bringing your fuel cost down. It is used for both small and large power requirements. The problem with natural gas generators is that you need to have facilities to safely store the gas tank on your site.

Natural gas generators are cost effective and can produce huge power outputs so are often used in industrial power generation.

What affects the diesel generator fuel consumption rate?

The more energy you require, the more fuel your generator will use. Try to reduce your machinery or appliances usage to reduce the load on your generator.

If your generator size is too large for your load or energy requirements, you could replace your generator with a smaller and more efficient unit to use less fuel bring your fuel cost down.


If you’re concerned about your fuel consumption or want to learn more about generator fuel, Solent Power are happy to help.

Contact us at Solent Power today, about your generator fuel use and perhaps there are ways we can reduce your generators fuel usage or offer alternative fuels such as ‘gas to liquid’ to reduce your emissions.

Paul Phelps
Paul Phelps

Paul is the MD of Solent Power and specialises in emergency power solutions, helping to protecting your facilities from power loss. Get in touch with us today to discuss the different power brands that we can offer and how they can suit your needs.

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