The quest for viable alternatives to petroleum-powered vehicles has taken full form over the past few years. The fluctuating price at the pump and widespread concern about the harmful effects of carbon emissions have caused major manufacturers to invest money and research into developing the most efficient form of alternative power. Showcasing the latest and greatest engineering and design achievements from an array of progressive automakers, the editors of The Robb Report Collection offer up a variety of cars from three categories—hybrid, diesel, and electric. The following pages highlight the most remarkable and relevant vehicles from the automotive companies that are pioneering a way to a cleaner future.

Fisker Karma S
The Fisker Karma S is ahead of its time. Before delivering a single one of its original Karma series sedans, Fisker Automotive unveiled its new retractable hardtop hybrid at the North American International Auto Show in January. The Karma S will use Quantum Technology’s Q Drive plug-in hybrid system to achieve a 300-mile electric-charge range with lithium-ion batteries and a 2-liter turbocharged 4-cylinder engine—the first 50 miles will be entirely electric-powered. Two drive modes will be available for different driving styles: Stealth mode will be the default setting and perform on battery power alone, while sport mode can be activated by flipping a paddle behind the steering wheel. Two electric motors will generate up to 408 hp—full power is only available in sport mode—and the Karma S will be able to reach 60 mph in less than six seconds. The first 250 vehicles will be numbered premium editions and deliveries are estimated to begin at the end of 2011. Official pricing has not been finalized, but is expected to be significantly higher than the current $87,900 Fisker Karma plug-in
hybrid sedan. —Paul Meyers
Fisker Automotive, www.fiskerautomotive.com

Lexus RX 450h
When Lexus engineers set out to develop the 2010 Lexus RX 450h, energy efficiency was a top priority. A new Eco drive setting modifies throttle response and reduces the air-conditioning system’s load on the engine when the driver hits the gas. The front-wheel-drive hybrid SUV returns up to 28 mpg in the city, but it is also available in all-wheel-drive for those interested in better handling. The RX 450h’s Hybrid Drive system—which pairs a 3.5-liter V-6 internal combustion engine to an electric motor—produces a total output of 295 hp transferred to the wheels via an ultra-smooth Continuously Variable Transmission.

The RX’s exterior features a refashioned front grille and blue-tinted badges, which showcase Lexus’ "L-finesse" design theme. A larger, more luxurious interior offers fresh technological touches like LED headlamps, a reverse camera with wide-view side monitor, XM NavTraffic and weather, a heads-up display, and, most notably, a new Remote Touch controller (similar in function and feel to a computer mouse) used to operate the navigation system, numerous audio controls, and personalization functions. —Kahn Reno
Lexus, www.lexususa.com

Lexus HS 250h
The Toyota Prius will soon lose some of its ecological luster. This fall, Japan will begin exporting the new 2010 HS 250h, as Lexus becomes the first luxury marque to offer a hybrid-only model. If the car looks vaguely familiar, however, that’s because it is basically a next-generation Prius, optioned to the hilt. Leather-trimmed seats are incongruous with plant-based recyclable plastics on the interior, but the emphasis here is on luxury. Radar-operated cruise control, heads-up display, and 18-inch wheels are available upgrades. Standard eco-friendly fare includes a 2.4-liter hybrid motor that uses 87-octane gasoline—the cheap stuff—to generate 187 hp. In addition, the HS 250h employs several neat tricks to maximize efficiency. For instance, a heat recovery system keeps the engine at operating temperature when it shuts off at stoplights. The windshield blocks infrared from the sun, reducing the need to run the air conditioner. Even LED headlamps contribute to improved fuel mileage, which should be in the neighborhood of 40 mpg. —Gregory Anderson
Lexus, www.lexususa.com

Cadillac Escalade Hybrid
The Escalade Hybrid from Cadillac is one clever cross-breed: the kind of vehicle General Motors builds well (sizable and smooth SUVs) and at the same time, the kind of vehicle it badly needs (a fuel-efficient gasoline-electric hybrid). Similar to the Chevrolet Tahoe Hybrid, the Escalade Hybrid—available in rear- or all-wheel-drive ($73,475 and $76,025, respectively)—employs an ingenious two-mode system that monitors a variety of factors, including vehicle speed and engine load, and subtly coordinates the power from a 332 hp gasoline V-8 and a pair of petite electric motors located inside the gearbox. Under light throttle and at speeds as fast as 30 mph, the Escalade Hybrid can shut down its V-8 engine and cruise on electricity alone, powered by a 300-volt battery pack beneath the rear seat. On the Interstate, the electric motor’s additional boost allows the system to deactivate four of the engine’s eight cylinders. The bottom line: It is as grand and capable as ever (able to trailer up to 5,800 pounds and seat as many as eight), but Cadillac’s Hybrid goes about its business with considerably less thirst. —Matthew Phenix
Cadillac, www.cadillac.com

Audi Q7 TDI
Thanks largely to the long-awaited introduction of ultra-low-sulfur diesel fuel at American filling stations, a diesel-powered SUV has become the latest must-have model among premier German automakers. This year Mercedes-Benz, an old hand at producing "oil-burners," is rolling out new ML-, GL-, and R-class diesels; BMW has the new diesel-driven X5 xDrive35d; and, not to be outdone, Audi now comes out swinging with the stylish Q7 3.0 TDI. Its 3-liter turbocharged diesel V-6 produces 221 hp and 406 ft lbs of torque. It returns an exemplary 25 mpg on the highway and boasts a bladder-busting cruising range of more than 600 miles. And, unlike those smoky diesel engines from the olden days, Audi’s TDI V-6 employs direct fuel-injection and a highly advanced multi-stage exhaust system to promote complete combustion and scrub engine emissions of particulate matter and toxic nitrogen oxides. Tailpipe gasses are laundered well enough to meet emissions standards in all 50 states—even squeaky-clean California. —M.P.
Audi, www.audiusa.com

BMW 335d
The notion of a diesel-powered BMW 3-series may be startling to American fans of the model, which has heretofore delighted drivers with one creamy, high-revving gasoline engine after another. But Europeans have known and loved the Munich-based automaker’s diesel models for years (they account for some 67 percent of BMW’s sales in Europe)—and for good reason. This year the $43,900 335d sedan (along with the $51,200 X5 xDrive35d SUV) arrives with a 3-liter in-line 6-cylinder engine that contrasts impressive efficiency and cleanliness with a rev-happy demeanor and truly substantial power. The engine utilizes twin turbochargers that deliver boost in sequence: a small one that spools up quickly for snappy throttle response and a bigger one that awakens at higher revs and gives a good, swift kick in the pants. The engine churns out a whopping 425 ft lbs of torque—42 ft lbs more than the M5’s mighty 5-liter V-10, and enough to launch the 335d to 60 mph in six seconds flat—all while returning a laudable 36 mpg on the highway. —M.P.
BMW, www.bmwusa.com

Mercedes-Benz GL320 BlueTec
With the seven-passenger GL320 BlueTec ($58,200), Mercedes-Benz is using blue to go green. The improved combustion of the BlueTec engine efficiently uses ultra-low sulfur diesel—in addition to a technologically advanced exhaust purification process that employs a urea-based solution called AdBlue—to reduce emissions. Nitrogen oxide—a harmful byproduct that is higher in diesel fuel than gasoline—is broken down into ammonia when AdBlue is injected into the exhaust flow and is released as harmless nitrogen and water vapor. On average, the 8.5-gallon AdBlue tank requires service every 10,000 miles.

The GL320 BlueTec’s V-6 engine achieves an EPA estimated 23 mpg on the highway, but still has 210 hp and 398 ft lb of torque for pulling power. The GL320 BlueTec, the R320 BlueTec ($49,150), and the ML320 BlueTec ($48,600) meet emission standards in all 50 states. —Hayley Lerch
Mercedes-Benz, www.mbusa.com

Touareg V6 TDI
Volkswagen is cleaning up the dirty reputation of most SUVs with the release of the Touareg V6 TDI, available in the U.S. this spring. Similar to the system on Mercedes-Benz BlueTec vehicles, the TDI’s patented DeNOx system converts nitrogen oxide from the exhaust gas into nitrogen and water using AdBlue. Contained in a 4.5-gallon tank under the spare tire, this system reduces nitrogen oxide emissions by up to 90 percent. The Touareg’s turbocharger helps achieve an EPA estimate of 25 mpg on the highway and delivers 221 hp and 407 ft lbs of torque to all four wheels—unfortunately, it also results in noticeable turbolag upon acceleration. Audi will equip its forthcoming diesel-powered Q7 TDI with the same 3-liter V-6 turbocharged motor, which should make for an equally quiet (and hopefully smoother) ride. —H.L.
Volkswagen, www.vw.com

Tesla Roadster Sport
It may plug into the wall, but the sensational Tesla Roadster is nobody’s golf cart. The battery-powered two-seater—jointly designed with British sports-car maker Lotus—is already the literal and figurative buzz of the industry, but Tesla now ups the ante with the even more enticing Sport model. Adding $19,500 to the car’s $109,000 base price, Sport specification juices the 248 hp electric motor to a stout 288 hp, and adds a revised suspension with driver-adjustable dampers and antiroll bars. Black-finished forged alloy wheels with Yokohama ultra-high-performance tires round out the package. While the standard car zaps to 60 mph in 3.9 seconds, the Sport accomplishes the feat in a mere 3.7 seconds—for just pennies per mile. As ever, ownership requires patience: The wait-list is more than 1,100 names long, and the time from order to delivery, according to the company, is at least a year. Of course, buyers currently awaiting delivery of a standard Roadster are welcome to cough up the extra cash and upgrade to the Sport. —M.P.
Tesla, www.teslamotors.com

Cadillac Converj
Making its surprise debut at the North American International Auto Show in January, Cadillac’s Converj represents the convergence of luxury and conservationism.

Designed as a two-plus-two coupe, the four-passenger concept car uses the Chevrolet Volt’s electric propulsion technology—composed of a battery pack, an electric drive unit, and a 4-cylinder gasoline engine—to drive its front wheels. The battery pack contains 220 lithium-ion batteries, which combine to provide the car’s primary power source. The car promises to travel up to 40 miles on battery power alone, whereupon it will switch to extended-range mode, in which the 4-cylinder engine acts as a generator to recharge the batteries. The electric drive unit develops 273 ft lbs of torque and 161 hp, which should impart instantaneous thrust and a theoretical top speed of 100 mph.

In practice, a production version of the car may lose its solar panel roof, wool carpeting, and silk headliner, but in theory, at least, the Converj represents the way forward for General Motors. —G.A.
Cadillac, www.cadillac.com

Dodge Circuit EV
Chrysler may have bet the farm on fire-breathing Hemis, but they’re quickly playing catch-up by developing several electric concept cars. The sexiest of the group is the Dodge Circuit EV, a tiny but fierce two-seater that echoes the spirit of another voltaic sports car: the Tesla Roadster. Also based on a Lotus chassis, Dodge’s EV packs an absurd 480 ft lbs of torque into its pint-sized package—a full 204 ft lbs more than its Silicon Valley–based rival. Acceleration is swift but brutal, offering an eerily quiet experience that’s accompanied by the subtle whine of phase shifting as the engine unspools. A regenerative braking system diverts energy back to the lithium-ion cells sitting just behind the passenger compartment, enabling a range of 150 to 200 miles. A test program will allow 100 consumers the opportunity to determine which electric vehicle gets produced in 2010. Our vote goes to this thrilling roadster, which might enable Chrysler to honor its muscle car roots while embracing a brave new future. —Basam Wasef
Chrysler, www.chryslerllc.com

Mini E
The BMW Group is taking the efficiency of its petrol-powered progeny to another level with the release of 500 zero-emission electric Mini Es. While a dark silver exterior with bright yellow accents sets the Mini E apart, the two-seat configuration breaks from the traditional four-seater, making for an even more mini Mini. The backseat is home to the car’s lithium-ion battery, which requires three hours’ worth of juice at the Mini E charging station installed by the company in the lessee’s garage. When the gas pedal is released, the electric motor acts as a generator and power is fed back to the battery, allowing the car to travel more than 150 miles under ideal conditions. Though the 201 hp Mini E picks up speed going from zero to 60 mph in 8.5 seconds, the abrupt jolt experienced upon decelerating may surprise drivers. Still in its developing stages, the Mini E is only available for a one-year lease to selected individuals in the metropolitan areas of California, New York, and New Jersey. —Hayley Lerch
Mini, www.mini-e.com