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In 1991, I attended a technical presentation at Volvo Cars in Sweden. The subject was the future of the automotive powerplant. Electric cars were the hot buzz with many industry observers, and several manufacturers were planning to build them. Volvo's experts dismissed such programs out of hand. Hydrogen was going to prove to be the ultimate answer, they said, and predicted it would take fifteen or twenty years for the dawn of this new age to be realized.

They were optimists. Thirteen years later, hydrogen still looks to be fifteen or twenty years down the road. But the industry consensus now is that hydrogen will, indeed, be the ultimate solution, both for emissions reasons (hydrogen is zero polluting) and for political ones (ending dependence on foreign supplies of petroleum being at the top of the list). In fact, hydrogen-compatible engines are already here. The main problem is obtaining the hydrogen to fill the tank.

Although hydrogen is a physical element, it does not exist by itself in nature. It is always attached to something else, usually oxygen. As I write this, I am sipping hydrogen. Specifically, I am halfway through a cup of coffee that is, when you get right down to it, flavored water, and water, as any school boy knows, is two parts hydrogen and one part oxygen. Good ole H2O. The first person to figure out how to extract that hydrogen commercially at a price the average consumer can afford will be richer than Bill Gates.

As for electric cars, almost exactly one hundred years ago no less a figure than Thomas Edison dedicated his considerable resources to an all-out attempt to build a competitive one. He failed. In the 1990s, the industry again tried mightily to meet the challenge, but now has pretty much thrown in the towel. The electric car has proven itself to be a technological dead end today for all the reasons the Wizard of Menlo Park came up short at the turn of the last century: There is just no way to build a battery that is cheap enough, light enough, long-lived enough, and that packs enough charge to be truly practical.

The interim solution seems to be hybrid technology, i.e., combining the best features of electric and gasoline technology to give us vehicles that are cleaner and more economical until that far off day when hydrogen becomes widely available. To that end, GM launched the Chevy Silverado and GMC Sierra Hybrid pickups during the 2004 model year. The hybrid option is available on two- and four-wheel-drive Extended Cab Silverados and Sierras. They are being sold in limited quantities to retail customers in California, Washington (State), and Oregon for 2005. Our test vehicle was a Silverado equipped with four-wheel-drive.

The Vortec 5300 V-8 engine delivers 295 horsepower (220 kw) and 335 lb.-ft. (463 Nm) of torque — the same as its non-hybrid counterpart. Yet there's something the Silverado and Sierra Hybrid provide that standard editions do not: these trucks are essentially mobile power-generating stations, with four 120-volt/20-amp electrical auxiliary power outlets (APO). The power outlets are located under the rear seat of the cab and in the pickup bed. Customers can conveniently operate power equipment without taking up the bed space typical portable generators would use.

A key to the hybrid's fuel efficiency is its ability to automatically stop and restart the engine under different operating conditions. Instead of a conventional starter motor and alternator, the hybrid pickups use a compact 14-kw electric induction motor — or starter generator — integrated between the engine and transmission. The starter generator provides fast, quiet starting power and allows automatic engine stops/starts to conserve fuel. It also smoothes out any driveline surges, generates electrical current to charge the batteries and run auxiliary power outlets, and provides coast-down regenerative braking as an aid to fuel economy.

The starter generator and torque converter are mounted in a concentric arrangement between the engine and transmission, without requiring additional powertrain length. A uniquely designed, electro-hydraulic power steering (EHPS) system provides variable-effort power steering, even when the engine shuts off to conserve fuel. The EHPS "powerpack" integrates an electric motor, a hydraulic pump and an electronic control module; it is powered by the truck's 42-volt battery pack. The EHPS also provides power assist for the brake system's Hydroboost hydraulic brake booster.

The three valve-regulated, lead-acid batteries store power for the 42-volt system. Lead-acid batteries are less costly to replace than nickel-metal hydride batteries, have a 50- to 55-amp-hour capacity and a projected four-year lifecycle. The batteries are stored in a single energy box that is mounted under the rear seat. They power only the EHPS and the starter generator. A conventional 12-volt under-hood battery powers all the other normal electrical items, such as lighting, the driver information center and the sound and entertainment systems.

Sweeping aside the mumbo-jumbo, what happens here is that the gasoline engine cuts out whenever you pull to a stop and then is restarted by the starter generator system when you apply pressure once more to the throttle. This addresses the greatest inefficiency of the current gasoline engine, namely that you are wasting fuel each time you sit at a red light, or in gridlocked traffic, or in front of your Aunt Mathilda's apartment building waiting for her to come down. We really do a lot of sitting in our cars and trucks with that engine running, merrily gulping gas and producing little or no benefit in return. With a hybrid system you pull up to a red light, the engine quits, you wait in silence, the light changes, you hit the accelerator, the engine immediately springs to life and you pull smoothly away. GM says the transitions are "seamless" and won't even be noticed by the driver. This is hype. When your engine dies, you know it and the sensation is eerie.

But the system IS pretty slick. The only real problem I noted was the lack of engine braking power at standstill. This is logical — indeed, inevitable — when you think about it. Without realizing it, we all expect our gasoline engines to help slow us down when we want to slow down, and to help hold our vehicles in place on hills as we wait for traffic lights to change and so on. The absence of the engine's holding power on inclines is especially unnerving at first. When you hit the accelerator in such situations, there is often a brief lag before the engine fully kicks in, and, during that lag, you can easily start rolling backwards — and right into the car sitting behind you. I came within an ace of having a minor collision this way. You soon learn to keep your left foot firmly planted on the brake pedal until the vehicle actually begins to move forward.

The other, more important, downside to the hybrid system is that it really doesn't succeed very well in its primary mission, i.e., saving fuel. GM claims a 13 percent improvement in fuel economy over the straight gasoline versions of the same trucks. Possibly so, but that translates into less than 2 mpg, which hardly seems worth the candle. (The Silverado Hybrid is rated at 17 mpg city, 19 mpg highway.) The hybrid option costs $2,500, so you would have to save more than a thousand gallons of gas at current prices just to come out even. According to my crude calculations, that would translate into roughly 15,000 miles of driving, which is what an average person does in a year. So during the second and third years of ownership you might actually start to turn a profit. Unfortunately, you would then run smack dab into the fourth year when the truck's 42-volt battery pack is due to reach the end of its life expectancy. That would almost certainly be a real kick in the exchequer and eat up much — if not all — of the money you had saved.

As noted earlier, one interesting feature of the Silverado Hybrid is that the system doubles as a mobile power generator. Next time there's a power outage in your neighborhood, just run an extension cord out to your truck and you have enough juice to power refrigerators, lights, drills, saws, computers and other electrical appliances that use standard household voltage! The photo here shows the first shipment of Silverado Hybrids being loaded at the Manheim Detroit Auto Auction in Romulus, Michigan, in August and bound for Florida. GM planned to send as many as fifty trucks to the hardest hit areas of Florida where more than a million residents were still without power after Hurricane Charley roared through the central part of the state.

In sum, it was an interesting test. I don't think GM's hybrid technology is quite where it needs to be to offer a real boon to consumers, but, within its limitations, it works and works well. As for the Silverado itself, hybrid technology aside it proved to be a very pleasant truck to drive. My only complaint was the amount of wheel hop you get on any kind of slick surface in two-wheel drive mode. This is one vehicle where four-wheel drive helps a lot even in normal driving situations. But it is easy to see why the Silverado is Chevy's best-selling vehicle. It offers solid value at prices that start at around thirty grand and go as high as your needs and wallet will take you. R&D