Heavy vehicles use more fuel than lighter cars, so the weight is everything for an environmentally friendly vehicle. The force needed to accelerate a vehicle is directly proportional to the weight of the car.
It is important to utilize the fuel as well as possible. Electric motors are considerably more efficient than combustion engines, the full benefit of 43 percent of the fuel energy.
Air resistance accounts for a large portion of a picture energy losses. Therefore, it must be designed so that the air has minimal resistance. Vehicle aerodynamics is improved, for example with a minimal frontal surface.
The friction between the tires and the road will cost lots of energy. Here, the choice of tires big role, but it applies also largely to reduce friction in the shock absorbers and the mechanical parts.