2. What is grey energy?

Some objects, such as a refrigerator or a car, consume energy when they are used: electricity for a refrigerator, gasoline or diesel for a car with an internal combustion engine. For the user, this is the energy needed to use the object throughout its life: this is operational energy. It is also sometimes referred to as direct energy.

The manufacture of the object, its maintenance and end-of-life management also require a quantity of energy that is rarely taken into account, as it is the responsibility of external economic agents such as the manufacturer,...