How Much Fuel Does A Standby Generator Use?

The amount of fuel a standby generator uses depends on its size, engine, fuel type and electrical load. A generator operating at a higher load will generally consume more fuel than the same generator operating at a lower load.

Fuel consumption figures provided by the generator supplier can help you estimate how much fuel is needed to keep a generator running during an extended power outage.

How do you calculate standby generator fuel consumption?

Generator manufacturers typically provide fuel consumption figures at various load levels, allowing you to estimate usage under expected operating conditions. To calculate the approximate fuel required, multiply the expected fuel consumption per hour by the number of hours the generator needs to operate.

For example, if a generator consumes 20 litres of diesel per hour under the anticipated operating conditions, 24 hours of operation would require approximately 480 litres of fuel. This is an illustrative calculation only, however, as actual consumption will vary according to the real-life load and operating conditions.

When planning fuel storage, allow for the usable tank capacity rather than its nominal volume, and consider your required operating autonomy, the fuel delivery arrangements, and an appropriate contingency plan if you experience changing demand or a delay in replenishment.

Can a standby generator's fuel capacity be extended?

Yes. Depending on the generator and installation, fuel autonomy can often be extended using a larger base tank, an external bulk storage tank, or an appropriately designed automatic fuel-transfer system. These arrangements can help support longer periods of operation without relying on immediate fuel deliveries.

The right solution depends on the generator's specification, available space, expected runtime, and site requirements.

What should you consider when increasing fuel storage?

Additional fuel storage requires careful planning. Considerations include the location and capacity of the tank, safe fuel transfer, leak prevention, access for refuelling and maintenance, and applicable fire safety and environmental requirements. Diesel fuel quality must also be managed, particularly where fuel may be stored for extended periods.

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