The sQuba is powered by three electric motors. One runs the wheels, one runs the propellers in back, and one runs the water jets in front that control the orientation of the car. Of course, this vehicle would be impossible with an internal combustion engine (combustion requires air...right?) so they had to go all-electric. Lithium ion batteries power the motors.

Emissions Free On Land, and in Water: The sQuba | EcoGeek