It might surprise you that the cost to offset your vehicle emissions is only 2.5-3% of the annual fuel bill, much less than the average fluctuation in fuel prices experienced in the past 12 months.

Its easy to offset the greenhouse gases from the combustion of fuel in your company operated cars, trucks, mobile plant and other vehicles. Here are 3 simple steps to follow to obtain accurate emission estimates and achieve genuine carbon neutrality for your vehicle fleet.  The same steps can be applied to your private vehicles too. Note: to calculate emissions from vehicles your company doesn’t operate such as trains, planes, taxis and rental cars, there are different approaches which will be covered in a future blog.

 Step 1: Gather activity data

Gather all the fuel receipts for the previous financial year and total up the number of litres of each type of fuel used by each vehicle.  It is important to retrieve the data for ALL vehicles for the WHOLE year so the information is complete.   Do not use kilometres travelled and average fuel efficiency for this purpose.  Get the actual consumption of fuel to achieve the most accurate estimate. Do keep records for reporting and verification purposes.

Example: Small fleet of trucks

During the 2014-15 financial year a company purchased 100,000 litres of E10 petrol and 500,000 litres of diesel for the vehicle fleet.  The information was readily available from the fuel cards issued to staff with company cars and trucks.

Step Two: Calculate emissions

Next simply convert the number of litres into kilolitres by dividing by 1,000, then multiplying this figure by the emission factor in the table below to get the number of tonnes of CO2-e.  The little “e” means that the total will include the other greenhouse gases – methane and nitrous oxide as well as carbon dioxide. If any of the vehicles have used biodiesel such as B5, B20 or B100 or a petrol/ethanol blend such as E10, just calculate the proportion separately then add up the total. Too easy!

Example: Small Fleet of trucks

The table shows that the total emissions from the car fleet in the above example were estimated to be 1,565 tonnes.

Type of fuel used

Kilolitres of fuel


Emission Factor GHGs *

Tonnes of CO2-e













LNG (light duty vehicle)


LNG (heavy duty vehicle)











* Source of emission factors:  Table 4: Fuel combustion emission factors – fuels used for transport energy purposes. The National Greenhouse Accounts (NGA) Factors, December 2014  prepared by the Australian Government Department of the Environment for use by companies and individuals to estimate greenhouse gas emissions. 

Step Three: Purchase offsets

Go on-line to find a reputable carbon offset retailer, then purchase offsets for the number of tonnes you calculated in step 2.  To avoid the risk that the offset does not represent genuine emission reduction (or removal from the atmosphere), make sure that you only EVER purchase verified carbon offsets. Reliable verifiers include, but are not limited to, VCS, NCOS, Gold Standard, Gold Power and Greenfleet. Some sellers will allow you to choose the actual project that your money will help fund such as Tasmanian native forest protection, Australian wind energy or sustainable development projects in third world countries.  Currently carbon credits will cost between $13 and $33 per tonne. For more information and advice go to the independent source: 

Example: Small Fleet of trucks

The annual fuel bill in our example was $840,000 ($1.40/litre average fuel price x 600,000 litres) and at $15/tonne, the carbon credits will cost 2.8% of the total fuel bill .

How we can help

Enviroease can develop a carbon reduction program for your company and find projects that may be eligible for state or federal government assistance. We are familiar with the Emissions Reduction Fund, Renewable Energy Target and NSW Energy Savings Scheme and VictorianEnergy Saver Incentive. Feel free to send an email to me (Suzy) at to find out more.