Desert Fuel has chosen to use multiple sources of energy. 

• The first choice of energy is solar energy.  Solar energy is free, easily captured, and used through the use of solar cells on Prototype 2's hood and roof.  The exposed surfaces yield approximately 20 free miles of travel a day.  The user need never connect to an electrical grid or worry about refueling if their commute is less than 20 miles per day on an average summer day. 
• The second choice of energy is electrical energy, which can be accessed from any wall outlet and can be programmed by the user to decrease charge time if higher current facilities are available.  Since many people have outlets available where they park their vehicle, it is important to have a standard connection on a vehicle so that no specialty wiring is needed. If a user has a short period of time, the vehicle will also be equipped with high current outlets and the user can select the current level at which they wish to charge.  The electrical energy is good for in town and rural commuting, if the user wants to travel less than 70 miles and would prefer to use their vehicle in electric mode.
• A third source of energy is diesel or biodiesel fuel. Desert Fuel's Prototype 2 was redesigned for use with biodiesel fuels as they have the lowest carbon imprint of any fuel source as shown below:

Since the engine works with biodiesel, it will also work with diesel, allowing the user to use conventional diesel when none of the aforementioned fuel sources are available.