The car plugs into an electric outlet in the garage. Can run 50 miles on an electric charge, then seemlessly switches on the gas powered electrical generator to feed the electric drive (through the batteries not directly) with a range of about 500miles.

If you live less than 25 miles from your place of work, you can commute everyday without ever using a gallon of gas. If you drive more than 50miles round trip a day, you should expect more than 100miles/gallon when you need to use the gas.

They also sell solar panels to install on your garage so that you never plug into an outlet to charge it, unless weather doesn't allow a full charge by solar panel alone.

By the way, the "Q-drive" technology was developed for the military by Quantam technology to build an electric drive vehicle similar to the Hummer that is silent and has no emmissions or heat signiture. Pretty thoroughly tested platform that partnered with Fisker.