Biogas is the gas produced by the fermentation of organic animal or plant matter in the absence of oxygen. This fermentation is also known as methanisation.

Biomass :
In the energy sector, the term biomass covers all energies resulting from the decomposition of organic matter, used to produce heat, electricity or fuel.

Fuel wood:
Wood used to produce renewable, clean energy. The energy produced from wood combustion can provide enough heat to fully or partially cover needs in terms of hot water or heating.

Technology which makes it possible to produce both heat and electricity from fuel. This simultaneous production makes it possible to optimise installation yield by minimising primary energy consumption compared to separate production processes.

Energy dependence:
Ratio between net imports (balance of imports and exports) and gross domestic consumption.

Heat loss:
Amount of heat produced which is lost during fluid transport.
Renewable energy: Renewable energy is energy which can be used without depleting reserves. These include hydroelectric power, wind power, solar power, wave and tidal power, geothermal power and biomass.

Recovered energies:
Use and production of heat from waste or used fuels. (Example: household waste incineration etc.)

Fossil energy (or conventional energy):
Energy produced from the combustion of fossilised organic elements. The fuels which provide fossile energy are primarily oil, natural gas and coal. This combustion produces greenhouse gases.

Unavoidable energies:
Natural, industrial or heat energy sources which are lost if not immediately recovered: Biogas, domestic waste incineration etc. The heat produced by incinerating household or similar waste can be recovered and used in the district heating network with excellent levels of profitability.

Geothermal energy:
Geothermal energy is a means of producing heat using the earth’s energy. Geothermal energy uses the heat from low energy fluid for heating and hot water and high energy fluid for electricity.

Friction loss:
Expressed as a pressure, friction loss corresponds to the energy dissipated through the friction as a fluid passes through a pipe.
District heating / District heating network: Composed of a central boiler plant and a pipe network, it is used to supply public and private buildings with heating and domestic hot water.

Primary network:
Section of the district heating network located upstream of the sub-stations, which links these to the boiler plant.

Secondary network:
Network located downstream of the substations which connects these to the buildings to be heated. From a legal perspective, the secondary network does not form part of the district heating network managed by the district heating service provider.

Thermal solar energy:
Thermal solar energy is the transformation of solar radiation into thermal energy. The heat recovered is then redistributed to systems for domestic hot water or central heating. Thermal solar energy offers considerable economic and environmental advantages.

The sub-station is the name given to the installation connected to the central boiler plant and the buildings to which it supplies energy. It makes it possible to exchange heat between the primary network and the secondary network via a heat exchanger, this heat is then used to supply heating or domestic hot water to homes, buildings, offices or public facilities.

Ton of Oil Equivalent – unit of energy which corresponds to the energy released from burning one ton of oil.

Abbreviation used for Household Waste Incineration Plant