The road transport sector operates in a competitive environment with fuel as a large input. Even small improvements in fuel efficiency or changes in fuel costs can have a major impact on profit and competitiveness.
Energy loss from engines can account for 70% of fuel consumed, in the form of waste heat through exhaust and cooling systems. Alternative drivetrain technologies can reduce these losses and significantly.
There are numerous other energy efficiency opportunities, which are outlined below.
Detailed data collection and analyses of individual vehicles, drivers and routes provide the basis for improving fuel efficiency.
Road freight operators tend to keep aggregate fuel records across the entire fleet rather than on individual vehicles. This is insufficient to show which vehicles and drivers are performing well or poorly.
Potential engine and drivetrain improvements are largely dependent on the duty cycles of specific vehicles and tasks. These can be accurately determined using detailed operational data.
Fuel data should be captured for different segments of the fleet and on a vehicle-by-vehicle basis. Monitoring of fuel cards, vehicle management systems, GPS and telematics can be progressively improved to be more cost effective.
Fuel consumption and productivity should be analysed in context of load weight using a metric such as ‘per tonne-kilometre’, or by volume for some duty cycles. Most trucks are not equipped to accurately measure load weight but can be retrofitted with onboard scales at reasonable cost.
Improved driver skills can bring large benefits to a company’s fuel efficiency. Energy consumption can vary by as much as 30% among drivers, even for the same route. Companies can invest in driver training such as:
- anticipating traffic
- minimising idling
- route planning
- eco-driving practices such as smoother braking and acceleration.
Computer programs and simulators can assist in this training.
Route planning and load consolidation
Route planning can reduce distance travelled, improve fleet utilisation and avoid traffic congestion.
Consolidate multiple deliveries by combining loads into a single vehicle and trip. Also, consolidate loads from multiple smaller vehicles into larger vehicles to maximum capacity, including the use of double-stacked trailers. Longer combination vehicles (LCVs) with multiple or longer trailers are up to 20% more fuel efficient than typical combination trucks.
Computer-based vehicle booking can help reduce fleet size and minimise total distance driven. Review of GPS data can reveal inefficient routing and most efficient vehicles. Some GPS devices can also receive real-time data on traffic congestion and crash sites.
Numerous websites and apps exist to facilitate easy back loading of freight so less fuel is wasted on unloaded return trips.
Average speed policy
Reducing speed can yield significant fuel savings. Aerodynamic drag increases with the square of the speed and becomes the major contributor to power requirements at speeds faster than 80 km/h. Reducing highway speed from 100 to 90 km/h can reduce fuel use by nearly 10%, and can diminish tyre wear, driver stress and crash risk.
In developing a recommended highway speed, companies need to consider labour costs and logistics, rest breaks and delivery schedules. All of these are affected by reduced speeds.
Maintenance programs can reduce fuel consumption rates by ensuring vehicles are tuned for optimal performance. The potential for fuel savings and emissions abatement may be as high as 10%.
There are regular formal maintenance checks that drivers should carry out, such as monitoring tyre pressures and replacing filters. Truck tyres inflated 10 psi below recommended air pressure levels can lower truck fuel efficiency by around 5%. Under-inflated tyres are also more prone to irregular tread wear.
The use of low-viscosity lubricants in maintenance programs can reduce friction and energy losses. The combined effect of low-viscosity synthetic engine oils and drivetrain lubricants can improve fuel economy by at least 3%.
Upgrade and optimise
At high speeds, aerodynamic drag can be the biggest energy drain on a heavy vehicle.
Trailer modifications, including smooth-side van trailers or side skirtings can reduce aerodynamic drag. Contrast this to drop decks with irregular shaped loads, stock crates and car carriers which can increase drag by 30%.
Worthwhile modifications include:
- roof deflectors
- chassis fairings
- under-hood air-cleaners
- vision systems that replace mirrors.
Innovations in complex rubber compounds, casing construction and tread design, have led to the development of low rolling-resistance tyres. Fuel savings of around 5% can be achieved for heavy vehicles.
Fitted with low rolling-resistance tyres, a combination long-haul truck can save over 2200 L of fuel per year.
Dual tyres can often be replaced with single wide tyres. Savings of around 10% are achieved by lowering the weight and rolling resistance of the tyres and wheels.
Some vehicle inclusions such as lighting, air-conditioning and power-steering can be optimised or alternatively powered.
LEDs use up to 90% less electricity than standard lamps. This saves electricity that would otherwise need to be generated by the engine-driven alternator. Consider replacing incandescent globes in new trucks with high output, low power, high-intensity discharge (HID) exterior and LED interior lights.
Better designed vehicle air conditioners can also reduce fuel consumption significantly. More efficient alternators and power-steering pumps can also improve fuel economy.
Vehicle mass and mass carried
Every 10% decrease in truck weight can reduce fuel use by 5% to 10%.
Ways to reduce vehicle weight include:
- lightweight trailers
- alloy wheels and super-single tyres
- optimising fuel quantity carried
- light stillage pallets.
The principles of fit-for-purpose procurement can be applied whenever vehicles are due for replacement or upgrade. Poorly specified trucks waste fuel and cost more to maintain.
Vehicle replacement and maintenance costs are also reduced when engines and drivetrains are not overworked. The principles apply equally to truck bodies and trailers as they do to the base vehicle.
Consideration should also be given to the most optimal timing of vehicle replacement. If analysis indicates company vehicles are much less efficient than newer models, accelerated replacement may be justified.
Optimising gear settings for the specific freight tasks results in a more efficient and frequent use of engine torque.
Automated manual transmission (AMT) systems can also reduce fuel consumption and carbon emissions by optimising gear shifting. An AMT converts a 3-pedal manual gearbox to a 2-pedal version by controlling the clutch function.
The duty cycle of the vehicle should be considered to ensure the benefits suit the application. AMTs are more suited to stop-start, high gear-shifting drive cycles.
In the heavy-duty segment, the main manufacturers all offer AMT systems. New versions of these gearboxes are bringing advanced features and integrated functionality with other onboard electronic systems.
Fully electric-powered light trucks are commercially available. As range is typically limited to a few hundred kilometres before recharging, they may be best suited as regional delivery vehicles, especially for ‘back to base’ applications. Large-haul electric trucks are currently under development.
Overall energy costs can be 80% less compared to diesel and petrol vehicles. Maintenance costs may also be reduced.
The upfront purchase price for electric drivetrains can be much higher compared to conventional road freight vehicles. Associated financing costs and the costs of back to base charging infrastructure should be factored into business case assessments. The $250 million Future Fuels Fund will include support for business fleet charging, including for heavy vehicles.
Hybrid electric drivetrains
Hybrid electric vehicles can deliver a significant fuel saving through battery storage of energy otherwise lost in braking. The stored electrical energy can be used to assist propulsion through efficient electric motors. Hybrids are well suited to urban freight operations with frequent stop-starts, which maximise the benefit of regenerative braking.
Mechanical hybrid-electric drivetrains
In a mechanical hybrid system, hydraulic accumulators (rather than the batteries typical of electrical hybrids) are used to store wasted energy. This can then be converted into force onto the drivetrain to assist in acceleration.
Biodiesel and ethanol
First generation biofuels are from conventional feedstocks such as sugar cane and animal fats, and use well proven conversion technologies. While not providing greater efficiency, biodiesel and ethanol can sometimes be cheaper, depending on the price of feedstocks. This can help contribute to company emission-reduction goals.
Biodiesel in Australia is made from plant and animal fatty acids and blended with conventional diesel at 5% (B5) or 20% (B20). Few manufacturers of vehicles sold in Australia currently accept the use of more than B5. Owners should check the recommendations of the vehicle’s manufacturer before using stronger blends.
Ethanol is a drop-in petrol substitute and is widely available in low-blend ratios (typically 10% E10). Higher blend ratio E85 is available in limited locations but requires engines specifically adapted to run on the fuel. The use of E10 will not affect warranties on most new vehicles, but compatibility can be checked via a range of websites.
See the department’s website to read more on biofuel quality issues and standards.
Electric truck conversions and applications
Companies are increasingly turning to electric truck manufacture and conversions to meet a variety of industry applications.
Australia’s first all-electric garbage truck commenced operations in Victoria’s City of Casey in late 2018. The vehicle features immediate torque, regenerative braking and a 180 km range.
DHL Express and Linfox are trialling SEA Electric’s vehicles in their supply chains. Woolworths have set a goal to transition their fleet to 100% electric.
To read more about these and other conversion projects, see the Australian Renewable Energy Agency (ARENA) website.
Second generation biofuels
Second generation biofuels, sometimes referred to as ‘advanced biofuels’ or ‘renewable fuels’, are made from non-food waste biomass. Production methods include biochemical and thermochemical processes.
Renewable diesel is chemically almost identical to conventional diesel and can therefore be used as a direct replacement without the need for blending. Cellulosic ethanol, made from waste plant material including leaves and stems, has the potential to lower carbon emissions while reducing pressure on competing land use.
Within Australia and globally, there is significant research into developing cost-effective second-generation biofuels. To read more, see the ARENA website.
Hydrogen fuel cells
The use of hydrogen fuel cells has been successfully demonstrated, however the relatively high cost of the technology remains a barrier to broader uptake. In the longer term, hydrogen fuel cells are expected to be economically suited to long distance freight as they can have a longer range than battery electric vehicles and a reduced refuelling time.
Hydrogen produced from renewable energy can have zero emissions, but conversion losses mean that ‘green’ hydrogen requires around twice the electrical energy to perform the same task as battery electric vehicles.
Next steps you can take
- Assess the energy efficiency of your business with the Road transport energy tool.
- Read more about how to conduct an energy audit.
- Research energy efficiency training options.
- See the Energy Efficiency Council website to find an expert or equipment provider.
- See the Truck Buyers Guide to help you choose a truck with the best fuel economy.
- Explore financing options:
Heavy Vehicle Safety and Productivity Program Australian Government
Biofuels and transport: An Australian opportunity (ARENA) Australian Government
Technology study: Alternative fuels (PDF 230 KB) NSW Government
A roadmap to accelerate energy productivity in freight transport by 2030 (PDF 6.00 MB) Australian Alliance for Energy Productivity (A2EP)