Automakers have been going green lately, unveiling a slew of fully electric and gas-electric hybrid vehicles aimed at eco-conscious consumers who also like to save at the pump. Hyundai recently showed off an alternative fuel that hasn't gotten a lot of attention: liquid propane.

The South Korean automaker seems to be a fan of the technology, which is cheaper and cleaner than gasoline. Hyundai previously revealed a concept version of the Elantra that utilized the alternative fuel. At the SEMA aftermarket parts show in Las Vegas, the automaker had a number of customized vehicles on hand, one of which was the propane-propelled Kia Forte Hybrid Concept.

The concept vehicle uses a partially-electric powertrain in conjunction with the liquid-propane fuel to come close to achieving no emissions. The rest of the vehicle was customized to highlight the theme of the show, with a green interior and a powerful 1200-watt stereo system.

However, because there is little infrastructure support for propane vehicles in the U.S., the concept is unlikely to make it to market anytime soon. Drivers might find the technology in some of Hyundai's upcoming cars for sale, like in the lithium-polymer battery packs that will be used in the Hyundai Sonata and Kia Optima hybrids.