5. Assessing grey energy: a complex problem

While the definition of grey energy is fairly clear, its precise evaluation is more complex. It is necessary to define the boundaries of the evaluation, as the result can vary greatly depending on the perimeter chosen.

Let's take a simple example to illustrate this point and show the complexity of the problem: that of an electric convector.

Energy in use, or operational energy, can be defined quite simply, even if its assessment involves considerable uncertainties in practice. In fact, users don't have a battery of measuring instruments in place at home to measure radiator consumption in real time. To make a reliable measurement, it would be necessary to measure the electricity consumption of each convector by installing it in a representative sample of the population. If each appliance is fitted with an electricity meter, it is possible...