In the auto industry, it’s increasingly hip to be green.

Question is, which company is the greenest?

This week at the Washington Auto Show, Green Car Journal will announce the winner of its annual Green Car Technology Award, recognizing inventions that are making the vehicles we drive more efficient and environmentally friendly. For the first time, the publication will also hand out awards for a Luxury Green Car of the Year and Green SUV of the Yea, celebrating carmakers that have built sustainable vehicles in classes not historically known for offering eco-friendly options.

For the Green Technology Award, the innovations earning high marks vary in terms of the type of cars they support, from those that run on hydrogen cells to plug-in electric motors to traditional combustion engines. It’s evidence that auto manufacturers have different views on which type of power systems are most likely to power the cars of tomorrow.

Here’s a look at the finalists for the technology award, and below that, click through for a rundown of the nominees for the first-ever Green Luxury and Green SUV awards. Check back on Thursday to find out the winners.

BMW i8 Plug-In Hybrid Powertrain

The BMW i8 sports car has two separate powertrains. The front two wheels are powered by a 96-kilowatt electric motor while a turbocharged 231-horsepower gas engine situated near the rear powers the back two wheels. The two drive systems can be used either one-at-a-time or simultaneously – the latter option delivering maximum power.

BMW i3 REx Range Extender

BMW has generated plenty of buzz by giving buyers of the electric i3 the option to tack on a so-called range extender – a small, two-cylinder gas engine that powers a generator to add another 80-plus miles to the car’s roughly 90 miles of purely electric range. However, by adding a extra weight, that option will slightly reduce the car’s all-electric range compared to the non-ReX version.

Chevrolet CNG Bi-Fuel Powertrain

Included in Chevy’s 2015 Impala, the CNG Bi-Fuel powertrain allows the vehicle to run on either standard gasoline or what’s known as Compressed Natural Gas (CNG), each of which has its own separate fuel tank. The cool thing about that CNG? It can be produced from processes that make use of organic waste materials such as table scraps and beer grains.

Ford F-150 Aluminum Body

Breaking quite literally from the mold, Ford has introduced a 2015 F-150 with a completely aluminum body, rather than using steel. The move shed 700 pounds from the steel-bodied version and therefore boosted the fuel economy. Critics worry the aluminum body won’t provide the durability needed for a pick-up, but Ford executives have insisted that won’t be a problem thanks to the use of thicker, heat-treated aluminum.

Ford 2.7-liter EcoBoost V-6

Ford is taking full advantage of that weight-reduction in the F-150 by inserting the smallest engine ever in the truck’s 68-year history. However, small does not mean weak for the company’s new 2.7-liter Ecoboost engine. The Aluminum F-150’s EcoBoost V6 still delivers 325 horsepower.

Honda 1.5-liter Earth Dreams Engine

The engines used in Honda’s new Earth Dreams drive system bring improved fuel-efficiency and lower emissions through a combination of weight reductions, direct-injection technology and other enhancements. The new engines come in a half dozen different sizes and help vehicles like the Honda Fit eclipse 40 miles per gallon.

Kia Soul Electric Powertrain

A new rival to the Nissan Leaf and Ford Focus Electric, the electric version of the Soul arrived in California dealerships this winter and offers 93 miles on a single charge. The company manages to only slightly reduce the passenger and cargo space with the electric powertrain, which comes equipped with a Braking Mode that allows the vehicle to slow to a near halt while simultaneously recharging the battery.

Tesla Dual Motor AWD

Tesla made a splash this fall by introducing a dual-motor power system for its fleet of Model S sedans, with one motor powering the front wheels and the other powering the rear wheels. Previous models have had a single motor that powered only the back wheels. The additional motor will add both stability and speed to the company’s most popular vehicles.

Volvo Drive-E

Some were surprised when Volvo sped into the headlines in October sporting a new four-cylinder engine with not one, not two, but three turbochargers, delivering an impressive 450 horsepower. The turbos are fed compressed air from an electrically powered compressor in the vehicle, which then pumps additional oxygen into the engine, resulting in extra power.

VW e-Golf Electric Powertrain

Volkswagen’s e-Golf is the automaker’s first production electric vehicle to be sold in the United States, a milestone that coincides with the Golf’s 40th birthday. The e-Golf, which looks nearly identical to its gas-powered counterparts, features a plug-in electric powertrain that pushes it to a combined fuel efficiency of 116 miles per gallon-equivalent (MPGe).

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