While electric cars are being touted as the automotive solution to gas guzzling cars, researchers in Sweden may have found another answer: air hybrid automobiles that could cut your fuel consumption by half, by using the energy generated from braking.

The energy is stored in the form of compressed air, and can be used to provide the engine additional power once the car is in motion.

Currently, electric cars and plug-in hybrids already use brake energy to power a generator that charges the batteries. But air hybrids would be much cheaper to manufacture, since the engine does not require any expensive materials and the system could work with gasoline, natural gas and diesel.

Even though air hybrids, also called pneumatic hybrids, are not yet in production, researchers at Lund University have recently developed a hybrid that primarily runs on gas, but can also tap into a tank of compressed air when needed.

The technology would be particularly useful during slow moving traffic or for buses in urban areas. “The technology is fully realistic,” Per Tunestal, a Lund University researcher, said. “I was recently contacted by a vehicle manufacturer in India which wanted to start making air hybrids.”

City buses could, in fact, reduce their fuel consumption by 60 percent, said the researchers. Another 48 percent of the brake energy, could be compressed and saved in a small air tank connected to the engine, and used at a later time, the researchers added.

Ford initially played around with the idea in the 90s, but lacked the research to make it into a reality. The hope right now is to convert research results from a single cylinder to a complete multi-cylinder engine, moving the concept a step closer to a real vehicle.

“This is the first time anyone has done experiments in an actual engine. The research so far has only been theoretical. In addition, we have used data that means we get credible driving cycle results, for example data from the driving patterns of buses in New York,” said doctoral student Sasa Trajkovic.

While air hybrids won’t cut fuel consumption as much as EVs would, a cheaper alt-fuel solution is definitely worth looking into.