The use of aluminium in the fabrication of vehicle bodies is significantly reducing the payload to unproductive gross load ratio of transport operators.
luminium processing company Hulamin executive director Richard Jacob says, "Vehicle manufacturing plants' equipment and fabrication techniques have always been dominated by steel. Over the years, however, designers have been getting better at using aluminium appropriately, to supplant steel in the manufacturing environment for specific applications."
Aluminium is light yet strong, and endlessly commercially recyclable, attributes which allow it to make a substantial contribution to reducing a fleet's carbon footprint.
Flat beds, trailers, tankers, dry bulk tankers, bulk tipper trailers, bulk containers and hoppers are regularly being manufactured using significant quantities of aluminium. Locally, fuel tankers have been fabricated from aluminium for almost 30 years.
Aluminium's density is one-third of steel, reducing a vehicle's payload body mass by 50% or more. Lower tare mass implies a greater payload, and less fuel a unit of payload. Substituting just 1 kg of automotive aluminium for 2 kg of steel in a vehicle prevents 20 kg of greenhouse gas (GHG) emission during the life of that vehicle of about 200 000 km.
Using 2006 production figures, the International Aluminium Institute calculated that the lightweighting of vehicles has the potential to remove almost 700-million tons of carbon dioxide emissions yearly from the transport sector's carbon footprint account.
Lighter vehicles also mean more payloads for every trip, requiring fewer trips and less fuel a ton of load. Hulamin's market manager of sheet and plate Brian Penfold says, "Using aluminium in a rigid body application offers from a 15% to 20% increase in legal payload. With the same legal weight axle, aluminium transportion manufacturers can produce vehicles with bigger tippers and tanks and other transport vehicles, allowing for marked improvements in payload."
While carrying more payload means fewer trips and less fuel a vehicle, it also has benefits on a fleet-wide level. "The from15% to 20% increase in payload means that a sixth or seventh vehicle, as well as the driver and the related administration, becomes obsolete," he says.
The Green Premium
Besides the reductions this delivers in terms of the carbon footprint, not requiring an entire vehicle helps offset the initial capital premium which transport operators have to lay out, between 20% and 40% , when choosing the lightweighting route.
Penfold says, "Assuming normal commercial terms of purchase, an individual vehicle pays itself back in about 18 months, owing to the increased payload. Where a fleet is concerned, the numbers look even better, since owners do not have the initial cost for a sixth or seventh vehicle, saving them anything up to R500 000 a unit for a primemover. The saving alone outweighs any additional capital cost of using aluminium."
Manufacturer and supplier of aluminium dry bulk tankers TEE buyer Krish Naidoo says that, despite the greater cost of an aluminium tanker as opposed to a steel one, fleet owners routinely choose this option. "An aluminium tanker weighs just over 5 t, while a steel one weighs almost 16 t. The aluminium operator is doing one trip for every two trips needed by the steel tanker, for the same payload." The company finds that its aluminium tankers are in demand all year round.
At the end of the vehicle's lifecycle, its aluminium content will allow it to make one final contribution to the reduction of GHG, through recycling. Over 90% of the aluminium in transport vehicles can be recovered and reused.
Smelting aluminium from bauxite ore uses a large amount of electricity. Aluminium, however redeems its green reputation in the recycling department. Only 5% of the energy required to produce the primary metal is required to recycle aluminium, which can be reclaimed over and over without affecting its quality. Over 75% of the aluminium ever produced is still in service.
Penfold comments, "The aluminium industry is systematically increasing the amount of secondary recycled aluminium being used. By reducing the demand for primary aluminium, the industry is significantly reducing the carbon footprint associated with the burning of coal, the basis of South Africa's electricity."