The road transport sector operates in a very competitive environment with fuel as a large input. Small improvements in fuel efficiency or changes in fuel costs can have a significant impact on profit and competitiveness.
There are numerous opportunities for the road transport sector to improve energy efficiency, such as upgrading vehicles and adopting better corporate, driver and fuel-consumption practices.
Data analyses of individual vehicles, drivers and routes provide the basis for improving fuel-efficiency. Many of the emerging engine and drivetrain opportunities are largely dependent on the duty cycles of the vehicles, which vary across a fleet.
Road freight operators tend to keep aggregate fuel records across the entire fleet rather than on individual vehicles. High-level aggregated data doesn’t show which vehicles and drivers are performing well or poorly.
Fuel data should be captured, at a minimum, for different segments of the fleet. Ideally, it should be on a vehicle-by-vehicle basis. Monitoring of data from fuel cards, vehicle management systems, GPS and telematics can be progressively improved to be more cost effective.
Importantly, fuel consumption and productivity should be analysed in the context of load weight using a metric such as ‘per tonne-kilometre’. Most trucks are not equipped to accurately measure load weight, but can be retrofitted at reasonable cost.
Improved driver skills can bring large benefits to a company’s fuel efficiency. Companies can invest in driver training and incentives to encourage drivers to enhance skills such as:
- anticipating traffic
- minimising idling
- route planning
- eco-driving practices such as smoother braking and acceleration.
Computer-based programs and simulators are available to assist in such training. Simple awareness-raising material such as newsletters and leaflets can also be effective.
Route planning and load consolidation
Route planning can reduce distance travelled, improve fleet utilisation and avoid traffic congestion.
Look for opportunities to deliver products to multiple customers by combining loads into a single vehicle and trip. Consulting with drivers and clients can highlight where to adjust delivery schedules around peak traffic periods.
Consolidate loads from multiple smaller vehicles into larger vehicles or load 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, where to reduce trips and distance, and the most efficient vehicles to use. Some GPS devices can also receive real-time data on traffic congestion and crash sites.
Numerous websites and mobile phone applications exist to facilitate easy back loading of freight, so that less fuel is wasted on unloaded return trips.
Average speed policy
Reducing speed can yield significant fuel savings. Aerodynamic drag increases exponentially and becomes the major contributor to power requirements at speeds faster than 80km/h. Reducing highway speed from 100 to 90km/h can reduce fuel use by nearly 10%, and can lower tyre wear, driver stress and crash risk.
In developing a recommended highway speed, companies need to take into account the costs and logistics of labour, rest breaks and delivery schedules all of which 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 5%.
There are regular formal maintenance checks that drivers should carry out, such as monitoring tyre pressures. Truck tyres inflated 10psi 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%.
Some vehicle inclusions such as lighting, air-conditioning and power-steering can be optimised or alternatively powered. For example, light emitting diodes (LEDs) use up to 90% less electricity than standard lamps, saving electricity that would otherwise need to be generated by the engine-driven alternator.
Companies can 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 reduce fuel consumption significantly. More efficient alternators and power-steering pumps can also improve fuel economy.
Optimising gear settings 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 takes a 3-pedal manual gearbox and converts it 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.
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
- examining fuel quantity carried
- light stillage pallets.
Innovations in complex rubber compounds, casing construction and tread design, have led to the development of low rolling-resistance tyres.
Fuel savings of 5% or more can be achieved for heavy vehicles. Fitted with low rolling-resistance tyres, a combination long-haul truck can save over 2200L of fuel per year.
Traditional 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.
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 induce 10% to 30% more aerodynamic drag.
Modifications also worth exploring include roof deflectors, chassis fairings, under-hood air-cleaners and truck vision systems that replace mirrors.
Alternative drivetrain engine technologies
Energy loss from engines can account for up to 70% of fuel consumed, in the form of waste heat through the exhaust and the cooling systems. Alternative drivetrain technologies can reduce these losses and significantly.
Fully electric powered light trucks with aerodynamic design are commercially available. Large-haul electric trucks are under development.
Overall running costs can be 80% less than for diesel and petrol vehicles. Maintenance costs are also greatly reduced.
Hybrid electric drivetrains
Hybrid electric vehicles can deliver a significant fuel saving. They 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 energy.
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. Whole-of-life costs 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.
Reviewing a company’s policy on vehicle replacement schedules is worthwhile. A longer retention time can justify an investment in vehicles that are more efficient, providing maintenance programs are adequate. Conversely, If analysis indicates company vehicles are much less efficient than newer models, accelerated replacement may be justified.
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 180km range.
DHL Express and Linfox are trialling SEA Electric’s vehicles in their supply chains. Woolworths who have set a goal to transition their fleet to 100% electric.
For more information see the Australian Renewable Energy Agency (ARENA) website.
Second generation biofuels
Second generation biofuels can be produced by converting chemical compounds in agricultural wastes into sugars which are then converted into ethanol.
Cellulosic ethanol has the potential to provide better energy balance, lower carbon emissions and requires less land use than starch-based biofuels.
Globally, there is significant research on the development of cost-effective second generation biofuels.
High hopes are held in the longer term for the use of algae as a biomass for the production of biofuels. It offers the possibility of a high yield — about 100,000L of oil per hectare compared to about 5000L per hectare for palm oil. It also does not require premium land meaning far less environmental impact than palm oil harvesting.
At present, it is expensive to cultivate algae and extract oil. To be commercial, high-volume production of low-value biofuel will need to go together with high-value co-products.
Challenges to development include optimising strains of algae, minimising risks of contamination and achieving the necessary scale of production.
Eco-driving Sustainable Freight
Overview of energy efficiency solutions Supply Chain and Logistics Association of Australia
Sustainable Development Scenario International Energy Agency
Transport Australian Industry and Skills Committee
The Engineering Sustainable Solutions Program Queensland University of Technology and the Natural Edge Project
Truck Buyers Guide Australian Government and New South Wales and Victorian governments