Porsche is scheduled to debut its 918 Spyder plug-in hybrid concept tomorrow at the 2010 Geneva Motor Show. Looking a bit like a Carrera GT evolved, the 918 Spyder is powered by both a 500-horsepower V8 and a pair of electric motors producing an additional 218 hp or 160kW. At full gallop, the concept can theoretically reach 62 mph in 3.2 seconds and reach a top speed of 198 mph. Porsche also claims that it can achieve 78 miles per gallon and emit just 70 grams of CO2 per kilometer.

The 918 Spyder plug-in hybrid concept is a parallel hybrid, meaning that it has two powertrains, gas and electric,  which can operate together or separately to motivate the wheels into motion. There are no less than four modes that configure the powertrains for anything from maximum efficiency to maximum performance and everything in between.

The E-Drive mode means pure electric power, and the car can reportedly last up to 16 miles on electrons alone. Next up is Hybrid mode, which is just what it sounds like and would probably be the mode for everyday around town driving. The Sport Hybrid mode again uses both powertrains, but tips the needle a bit more towards performance with most power reaching the rear wheels. Finally, the Race Hybrid mode means all systems are go for the lowest lap times possible. There’s an even a push-to-pass button that adds a bit of E-boost on the straights and, of course, regenerative braking is present and accounted for.