How to Calculate Generator Fuel Requirements for a Long-Term Rental

In case one has to rent a diesel generator due to some projects, ensuring the availability of fuel becomes equally important as opting for the right size of generator. For example, construction sites, industries, festivals, and other forms of temporary setups may require the operation of generators for several hours per day over an extended period of time. This would be helpful in fuel requirement estimation in advance.
 

1. Know the Fuel Consumption of the Generator

It all starts with knowing how much fuel the generator will burn. Most generator manufacturers will give the fuel consumption of generators in liters per hour (L/hr) for various loadings.

The fuel consumption of generators varies with the amount of load put on it. In other words, the generator will burn fewer liters of fuel per hour than the same generator at 75% or 100% loading.
 

2. Calculate the Expected Operating Load

Just knowing the generator’s capacity is not enough to estimate its fuel consumption. You will have to calculate the actual load that will be connected to the generator.

For instance, the rated capacity of the generator can be 250 kVA while the average load can be just 60% of this capacity. This means that you will use the relevant amount of fuel when calculating the consumption.

If there are fluctuations in the load during the day, you will have to calculate the consumption separately for each period.
 

3. Calculate Daily Fuel Consumption

If you are aware of how much fuel is consumed on an hourly basis, you will be required to multiply the same by the number of hours per day the operation runs.

Daily Fuel Consumption = Fuel Consumption per Hour x Number of Hours per Day

Thus, if your daily consumption is 20 liters per hour and it runs for 10 hours a day, then:

20 x 10 = 200 liters per day.

4. Determine the Fuel Consumption for the Rental Period

If the generator is to be rented for a considerable period of time, then the above formula can be used to determine the fuel consumption as follows:

Fuel Required = Daily Consumption of Fuel × Number of Operating Days

If the daily consumption of the generator is about 200 litres, and is to operate for 30 days, then:

200 × 30 = 6,000 litres

5. Account for Changes in the Load

The generators do not work at the same load all day long because construction machines, pumps, air conditioners, lights, and other loads can come on and off during various times of the day.

In order to have an estimate closer to reality, the working schedule can be divided into periods with different loads.

6. Plan Fuel Storage and Refuelling

For extended generator rentals, one must have a proper plan for refuelling. This must take into consideration the fuel consumption, delivery times, site availability and other safety aspects.

A good stock of fuel may assist in preventing any shutdown due to lack of fuel.
 

7. Check Actual Fuel Usage

The estimated fuel requirement must be matched against actual fuel used during the rent period. This will assist in identifying any abnormal performance of the generator or unusual fuel usage or change in site electrical load.
It will also contribute to improving fuel budgeting and future renting of the machine.

 

Calculating the generator fuel requirement for the extended duration of rental will not be all about assessing its kVA output. One must take into account the fuel consumption rate, load, daily running hours, rental duration, load variability, and refueling opportunities among others.

 

This way, the organizations will be able to allocate adequate budget on the fuel and manage their generator appropriately during the entire rental duration.