Road transport

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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 60 to 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.

Quick wins

Fuel data

Detailed data collection and analyses of individual vehicles, drivers and routes provides the basis for improving fuel efficiency.

Road freight operators often keep aggregate fuel records across the entire fleet rather than on individual vehicles. This is insufficient to show how vehicles and drivers are performing.

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.

Where possible, fuel consumption and productivity should be analysed in context of load weight using metrics such as ‘per tonne-kilometre’ or volume for some duty cycles. Many trucks are not equipped to accurately measure load weight but can be retrofitted with onboard scales at reasonable cost.

Driver practices

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
avoid traffic congestion.

Computer-based vehicle booking systems 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.

Consolidate multiple deliveries by combining loads into a single vehicle and trip. Consolidate loads from multiple smaller vehicles into larger vehicles to maximum capacity. This includes 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.

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

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%.

Drivers should carry out regular formal maintenance checks 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

Aerodynamics

At high speeds, aerodynamic drag can be the biggest energy drain on a heavy vehicle. The benefits of aerodynamic improvements depend on vehicle speeds and the vehicle duty cycle.

Drop decks with irregular shaped loads, stock crates and car carriers can increase drag by 30%. Trailer modifications, including smooth-side van trailers or side skirtings can reduce drag.

Other worthwhile modifications may include:

roof deflectors
chassis fairings
under-hood air-cleaners
vision systems that replace mirrors.

Under Australian highway conditions, aerodynamic improvements to heavy vehicles can provide fuel savings of 7% to 15%. Savings will depend on:

the extent of modification - for example chassis fairing only versus fairings plus additional side skirts
how modifications suit the vehicle design and operation. For example, roof deflectors are most effective when they are aerodynamically optimised and aligned with roof height and width.

Tyres

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, where replacement of dual tyres with wide single tyres is permitted.

Ancillary equipment

Some vehicle ancillaries 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 significantly reduce fuel consumption. More efficient alternators and power-steering pumps can also improve fuel economy. Upgrades can be considered if these components need replacement.

Vehicle mass and mass carried

Every 10% decrease in truck weight can reduce fuel use by 5% to 10%, where the duty cycle of the vehicle allows modifications.

Ways to reduce vehicle weight include:

lightweight trailers
alloy wheels and super-single tyres
optimising fuel quantity carried
light stillage pallets.

Procurement strategy

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 or are becoming costly to maintain, accelerated replacement may be justified.

Alternative approaches

Gear settings

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 transmission operation and gear selection 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.

Electric drivetrains

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. This is especially the case for ‘back to base’ applications. Electric trucks are developing rapidly, with larger rigid and articulated trucks entering the market.

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.

It is important to understand your fleet operations before switching to electric heavy vehicles. Electric trucks are more efficient and especially suited for duty cycles involving moderate loads where battery weight does not constrain payload.

Electric heavy vehicles may be feasible if:

the operating range is suitable
charging is available
vehicles can be charged during scheduled breaks or rest stops.

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

First generation biofuels are from conventional feedstocks such as sugar cane and animal fats. They use well proven conversion technologies.

While not providing greater efficiency, biodiesel and ethanol can sometimes be cheaper depending on the price of feedstocks.

Biodiesel in Australia is made from plant and animal fatty acids and blended with conventional diesel at 5% (B5) or 20% (B20) to meet applicable fuel quality standards. Some 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.

Second generation biofuels

Second generation biofuels, sometimes referred to as advanced biofuels or renewable fuels, are made from waste or non-food biomass. Production methods include biochemical and thermochemical processes.

For example 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.

Renewable diesel (also called paraffinic diesel) is a more advanced lower emission substitute for conventional diesel. It can be used as a direct replacement for conventional diesel and is used in much higher blends (up to 100%).

Supply of renewable diesel is currently limited but is expected to contribute to emissions reductions in future. Australia has renewable diesel standards in place to support industry development. See the department’s website to read more on fuel quality standards.

Within Australia and globally there is significant research into developing cost-effective second-generation biofuels. To read more, see the ARENA website.

Innovations

Electric trucks and buses

Battery electric technology and charging systems are advancing resulting in increased energy density and reduced charging times. Buses and rigid trucks operating in urban areas can utilise battery technology following set routes as they can recharge at a central location.

ARENA is investing in electric freight trials to test vehicle performance, charging needs, and grid impacts in real-world conditions. These projects are helping to:

de-risk investment
validate new technologies
build operational know-how across the freight sector.

Urban freight represents the most feasible immediate opportunity to electrify due to:

vehicle availability
shorter distances
operational patterns.

Regional and interstate freight represent opportunities as charging infrastructure develops. Shifting to electric trucks requires assessing fleet operations to focus on the most feasible duty cycles and routes.

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.

Hydrogen fuel cells are expected to be economically suited to medium to long distance freight in the longer term. They can have a longer range than battery electric vehicles and a reduced refuelling time.

Hydrogen produced from renewable energy can have zero emissions. However, conversion losses mean green hydrogen requires around 3 times the electrical energy to perform the same task as battery electric vehicles on a lifecycle basis.