May 14, 2010

KOMATSU LTD.

Komatsu has been selling a hybrid excavator in Asia for more than a year and has demonstrated them in the U.S.

FOCUS | General & Trade Contracting

Hybrid construction equipment technology drives forward

KORKY KOROLUK

corrrespondent

Driven by the need to produce machines that cost less to operate, and by regulatory pressures for lower carbon emissions, makers of construction equipment are spending a lot of time and money inventing and developing electric and hybrid drives to conventional hydraulic systems.

The word “hybrid” has turned into a sort of catch-all that can mean many things, but, typically, a hybrid drive allows the use of smaller diesel engines that can operate at the speeds at which they are more efficient and run more cleanly. Hybrid drives can recover and reuse energy that conventional drives waste as heat.

But what catches everyone’s eye is the advantage of lower fuel consumption than conventional systems, which can mean productivity gains, and, often, less maintenance.

An example is the D7E dozer which Caterpillar Inc. introduced last year, and which isn’t even marketed as a hybrid machine. Instead, the company emphasizes the innovative technologies included in the design.

The machine uses a diesel engine to drive a generator that runs the two electric motors that actually drive it.

“It can be considered a hybrid ...” says a company spokesman. But “unlike automotive hybrids, (the D7E) does not use a battery or capacitor to collect, store or release energy during operation.”

Instead, it captures reusable energy in a flywheel during braking, contributing to the over-all efficiency of the machines.

No matter what the technology is called, Caterpillar says the D7E “delivers 10 to 30 per cent greater fuel economy, greater productivity and lower lifetime service costs, compared with conventional designs of equal weight and horsepower.

All the major equipment manufacturers are exploring hybrid options to conventionally powered equipment.

Komatsu Ltd., has been selling a hybrid excavator in Asia for more than a year, and recently put several of the machines on a tour of the United States to introduce it to American operators.

Instead of using a diesel engine for power and a hydraulic motor to turn the superstructure, the hybrid uses a diesel engine, an electric-swing motor, a generator, a capacitor and pumps.

That, says Komatsu’s Armando Najera, “is a hybrid by every definition.”

The machine — the PC200LC-8 Hybrid —“recovers energy that would otherwise go unused, stores it and makes it available to do work.”

As the swinging superstructure slows down, kinetic energy is converted to electricity which is sent through an inverter and then captured by a capacitor.

Unlike a car battery that depends on a chemical reaction to produce energy, capacitors are able to produce the bursts of power needed for construction. That means less work for the diesel engine to do.

It’s a smart machine, Najera says, that “senses when there is a demand, and that’s when it kicks up and adds power to the system.”

The features that make hybrid machinery more productive and more friendly to the environment are expensive to develop.

Manufacturers all say they’ve spent tens of millions of dollars in research and development, and Caterpillar claims to have spent US$7.5 billion in R&D in the last six years. Ultimately, of course, it is the equipment buyers who will pay the price.

Manufacturers say, though, that although the up-front costs for the buyers will be high, contractors will find the equipment’s life-time costs are lower because of lower fuel costs, higher productivity, and longer life.

Still, Komatsu says its hybrid excavator will cost about $225,000, a 50-per-cent premium over a conventional excavator with similar capacity. And Caterpillar says the D7E sells for about $600,000, roughly 20 per cent more than the conventional D7.

Rob Bradford, executive director of the Ontario Road Builders Association, says the group’s members are certainly aware of hybrids, but they are aware, too, of the purchase price.

A concern he expressed was about maintaining a level playing field during the bidding process.

It’s tough, he said, to incur the expense of the new machines and still come in with a low bid if your competitors isn’t making similar investments. So it may be necessary, he suggested, for governments to introduce some sort of regulation, or contract language, to kick-start a move to hybrids.

That’s starting to happen in the United States, where some authorities have begun to write requirements for clean construction equipment into contracts for projects funded by public money.

The idea is to prohibit contractors from bidding if they don’t have equipment that meets current clean-air standards.

In the meantime, development work continues. Volvo, for example, has a hybrid wheel loader. It has both an electric motor and a diesel engine, both connected to a mechanical transmission.

The electric motor is powerful enough to move the loader from a standstill up to a speed where the diesel engine takes over. The system also runs as a generator/alternator for recharging batteries, and regenerative braking.

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