1. Identify energy sources, uses and data

First, we need to distinguish between energy consumption :

• by source, whether electricity, gas, fuel (diesel, petrol...), heating oil, coal, etc. ;

• for an identified area, either on the scale of an industrial site or a commune (with the consumption of each building, such as offices, residential buildings, factories, town hall...), on the scale of a building (consumption of each room), or on the scale of a room or workshop (consumption of each piece of equipment with production tools, computers, boiler...);

• by use, energy that can be exploited for different purposes, such as heating, domestic hot water, water treatment, cooling, lighting, ventilation, industrial utilities such as compressed air, heat or refrigeration production, electrical processes.