Last month Porsche revealed the 918 Spyder Hybrid at the Geneva Auto Show. The plug-in hybrid has a 15.5-mile all-electric range (AER) and a preliminary fuel efficiency estimate of 78 mpg. However, this is a Porsche and Porsches are best known for their speed. The 918 Spyder Hybrid has a zero to 62-mpg time of 3.2 seconds and gives drivers a whopping 718 horsepower to play with.

Although the vehicle is not currently available, it piqued a lot of interest from buyers around the world. According to a Bloomberg article, Porsche AG has a growing list of almost 900 potential buyers. Once the automaker reaches 1,000 interested buyers, production may begin.

According to Wolfgang Duerheimer, who was interviewed by Bloomberg last week at the Beijing Auto Show, “I’m confident that we will soon reach the threshold of 1,000. We need 1,000 seriously interested people to make a sound business case.” 

This hybrid is attractive to buyers because it can operate in an environmentally friendly fashion but can perform like a true sports car. The multiple driving modes do lead to a bit of a conundrum when determining overall fuel efficiency.

In his coverage of the Porsche 918 Spyder Hybrid for the Mother Nature Network, blogger Jim Motavalli said, “Determining fuel economy in cars like this is a bit of a risk, since the car operates in two distinct modes (with four variations, including both “sport-hybrid” and full-out “race-hybrid.”) It has infinite mileage if you putter around town, but it shoots into Hummer territory when you open it up at 180 mph on the autobahn.”

This all goes back to the green and greener conversation. Is it better to drive a greener vehicle? Many scientists and eco-advocates would say yes. Improving a 10-mpg SUV to a 20-mpg SUV will have a greater overall affect than improving a 40-mpg hybrid to a 50-mpg hybrid.

However, with the Porsche 918 Spyder Hybrid, the question of green or greener will need to be answered in a single vehicle. Driving in electric-only mode is certainly considered green but is driving 180 mph in a hybrid vehicle much greener than driving 180 mph in a non-hybrid?