The truck from outer space

It's called the Walmart Advanced Vehicle Experience (WAVE) truck and is a concept vehicle the American retail giant has developed with the help of iconic American brand Peterbilt. The WAVE was revealed at Walmart's recent Global Sustainability Meeting and is a one-off concept designed to explore ways that trucks can make less of an impact on the environment.

Walmart operates its own massive fleet of 7000-odd trucks that haul cargo from suppliers to its 4800 stores across the United States and cover millions and millions of miles in the process. It has a goal of improving the efficiency of its logistics network, delivering more cargo and driving less miles, but is also aware that new technology is needed to reduce the fuel consumption and the emissions produced by the semi trailers that move everything its sells.

That's where the WAVE truck comes in. "It may never make it to the road," says Walmart CEO Doug McMillon, "but it will allow us to test new technologies and new approaches." The WAVE is not just a flimsy prototype based on a striking design made for a truck show, but features some fascinating technology including a gas turbine generator and electric motor as well as some stunning carbon fibre elements. It features a special Great Dane trailer made almost completely from carbon fibre, which is know for being both strong and light.

The one-piece side trailer panels are 16.1 metres long and are thought to be the longest single piece flat carbon sections ever produced. By making the trailer box primarily from carbon fibre, the makers have managed to save approximately 1800kg in bulk. The front of the trailer box is also rounded for the best possible aerodynamic profile.

The WAVE cab comes straight from a science fiction movie, but there is a method to the madness. It was designed to cut through the air with the least amount of drag, with designers steering clear of a traditional cab. As a result the cab is shaped around a single driver's seat, with a bench for passengers behind that. There is also a sleeper bunk at the back of the cab. All up, Walmart says the WAVE truck is a considerable 20 per cent more efficient than most of today's truck and trailer combinations.

The powerplant that sits underneath the cab is particularly interesting. There is a gas tubine linked up to a battery pack that acts like a generator. Turbines were trialed as car engines back in the 1960s and Chrysler even built 50 turbine powered cars for a trial, but they have always been too noisy and too thirsty because they have to spool up and down for regular driving. However, the technology makes much more sense thanks to electrification.

The idea now is that the turbine spools up and then runs at an efficient constant speed generating electricity that is fed to a battery and on to an electric motor that propels the wheels. Running at a standard rate, regardless of whether the vehicle is cruising or speeding up and slowing down, allows for the best possible efficiency.

The WAVE creators say the turbine in its truck can run on gas as well as diesel, biodiesel, gas and potentially other fuels. It is not clear whether the turbine hybrid power train in the WAVE concept is actually operating as described at this stage or whether it can operate in electric only mode.

Of course, the big issue is going to be whether enough energy can be generated by the turbine hybrid powerplant to haul a heavy load of cargo for several hundreds of miles and there is also the question of how much fuel it will consume. Either way, the WAVE truck will at least make people think about ways to improve the efficiency of trucks and trailers and that has to be a good thing.