FleetSmart Profiles: Forestry

Stora Enso Port Hawkesbury Ltd. – Port Hawkesbury, Nova Scotia

Reduced Tare Weights Lead to Fuel Savings

Owner-operators hauling forest products for a multinational company in Nova Scotia are finding that reducing vehicle tare weights can significantly increase payloads and lead to fuel savings.

About the company

Stora Enso Port Hawkesbury Ltd., a Canadian division of a multinational company with annual sales of approximately $10 billion U.S., is in the forest products industry. The Port Hawkesbury, Nova Scotia, operation employs 61 contract drivers and trucks. The trucks travel a total of 5.4 million kilometres each year, for an average of nearly 100 000 kilometres per driver.

The company uses a combination of semi-trailers (typically tri-axle designs) and B-trains (typically with three axles on the front trailer and two on the rear trailer), many of which are equipped with loaders to improve their flexibility.

Most of the company's deliveries of forest products start on unpaved secondary roads, with about half of deliveries moving onto public roads. The roads pass through terrain that ranges from relatively flat to hilly.

In 1988, the company decided to mount a concentrated effort to improve fuel economy, increase payload and cut costs by reducing vehicle tare weights. Three opportunities were pursued:

• using smaller engines
• using lighter trucks and trailers
• removing the loaders from the trailers

No-frills equipment

As a second element of its strategy, Stora Enso approached drivers about the possibility of reducing tare weights by specifying basic "no-frill" rigs.

In 1989, an Ontario-based trailer manufacturer introduced a custom trailer with a drop frame that could reduce trailer weight by about two tonnes, decrease maintenance requirements and extend trailer life. The use of air suspension rather than springs on the trailers allowed drivers to weigh their loads with onboard pneumatic scales, helping operators achieve the maximum legal payload with little risk of overloading. Using this equipment, operators with tri-axle semi-trailers are now able to achieve average payloads of 33 tonnes, compared to 28 tonnes in 1987. By choosing vehicle specifications carefully, owner-operators contracting to Stora Enso Port Hawkesbury have also reduced tractor weights by about 900 kilograms.

Smaller engines encouraged

Today, 10- and 11-litre engines are available that offer the same torque and horsepower as 14-litre engines built in 1995, but weigh approximately 400 kilograms less.

In 1998, one owner-operator contracting to Stora Enso switched to a lightweight electronic engine in his truck and achieved instant fuel savings. Fuel consumption improved to 40 litres per 100 kilometres (seven miles per gallon), compared to 48 to 55 litres per 100 kilometres (five to six miles per gallon) for a conventional engine. The company estimates that, if the electronic engine was used across the 66-truck fleet, total fuel consumption would drop by up to 690 000 litres per year. Unfortunately, most owner-operators contracting to Stora Enso Port Hawkesbury have proved to be apprehensive about switching to the new engines.

Detachable loaders

Stora Enso is also promoting the use of a side-mounted detachable loader as a means of reducing the tare weight of self-loading trucks. Without the loader, tare weights drop from 14.5 tonnes to 11.5 tonnes – which means the company can increase the payload by three tonnes. However, while the technology is well proven, it has not been fully accepted by the owner-operators.

The use of B-train configurations, which are legal on roads that do not have bridges that limit vehicle weights, has also enabled Stora Enso to increase payloads. B-trains without loaders are hauling average payloads of 42 tonnes. The company is now moving 15 percent of its wood using these trailers.

What is reduced tare weight worth?

To help Stora Enso determine the monetary value of reduced tare weight, the Forest Engineering Research Institute of Canada analysed each component of the truck and trailer to account for the weight saved compared to the original component, the cost of the new component, and its ongoing maintenance costs over the five-year life of the truck.

The study revealed that most of the weight savings were gained from the use of new technology, such as air suspension, which is lighter than springs. The use of aluminum components also saved substantial weight – 64 kilograms per axle in the wheels and hubs; 40 kilograms for the fuel tank, and eight kilograms for the air tank. The new 10-litre engine, in addition to being lighter than the older 14-litre engines, costs less to buy and offers 15 percent better fuel economy.

How effective has the company been?

While most of the owner-operators now contracting with Stora Enso Port Hawkesbury are opting for lightweight trailers, opportunities still exist to reduce tractor weights by an average of 1.5 tonnes. By taking full advantage of the available technology when buying the tractor, trailer and loader, payload could increase by six percent. Further improvements in tare weight are being investigated based on lighter engines and lighter, stronger rigs.

Stora Enso also promotes the use of fuel-efficient equipment and lightweight components in its woodchip hauling operations. As a service to owner-operators, the company is launching a program that will track machine utilization rates and payloads to show contract drivers how they are performing.

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