Congratulations on the Solectria Force! To make a somewhat meaningful electricity - gasoline comparison, there are several posts in the Fossil Free forum regarding conversion from kWh to energy content in gasoline. In short, if you know how many kWh your Force uses to travel X number of miles, you can use the converter here:
(link repeated here from the FF forum / bennelson)
Convert gallon [U.S.] of automotive gasoline to kilowatt-hours - Conversion of Measurement Units
As an example, I use about 254 watt-hours per mile in my Citicar. That translates to the equivalent energy of 140 MPG.
As car as cost goes, the local electric utility gives me $9.00 (about 85 kWh) a month credit for having a small EV. Comparing cost VS gasoline use wouldn't really work, since my EV electricity miles are essentially free.
Maybe when I grow up I'll have more than a golf cart on steroids - but it is just about perfect for my 10 mile round trip commute.
Again, welcome!