The fuel cell of the FCX is small enough to fit in between the driver and passenger seats. This new fuel cell stack is 20 percent smaller and 30 percent lighter than the current FCX stack, yet its power output is 14kW greater. Overall, the power plant is about 180kg lighter than that of the current FCX and about 40 percent smaller in volume. The result is improved energy efficiency and performance along with a more spacious interior. As an auxiliary power source, the FCX Concept carries a compact, high-efficiency lithium ion battery, helping with increased power output and vehicle range. The vehicle is also highly energy efficient at around 60 percent -- approximately three times that of a gasoline-engine vehicle, twice that of a hybrid vehicle, and 10 percent better than the current FCX.