Wood is undoubtedly the first energy source harnessed by humans — the use of fire dates back to prehistoric times. This energy source is still widely utilized throughout the world, for domestic purposes and industrial applications.
Renewable and abundant, this resource falls under the heading of traditional biomassIn the energy sector, biomass is defined as all organic matter of plant or animal origin... and is widely used throughout the world. In developing countries, 2.5 billion people rely solely on burning wood and animal dung for heating, lighting and cooking.
Wood Energy, the Main Renewable Energy Worldwide
Wood energy is often overlooked in world energy mixThe range of energy sources of a region. statistics, because its use is mostly non-commercial. However, it is estimated that at the start of the 21st century, traditional biomass provides about 1 billion ton of oil equivalent (toe)Unit of energy measurement corresponding to the energy produced by the combustion of a ton of oil... (toe) per year, which is about 10% of the world’s primary energyAll energy sources that have not undergone any conversion process and remain in their natural state.. consumption. But on a local level, particularly in much of Africa, it accounts for over 90% of domestic consumption.
In France, roughly 7 million households (out of 30 million) use wood, mainly logs, as a main or additional source of heating. Its use is on the rise, up from just 6 million households in 2000, but the figure fluctuates slightly from year to year depending on temperatures in winter. Wood is therefore the main renewable energyEnergy sources that are naturally replenished so quickly that they can be considered inexhaustible on a human time scale... in France.(1)
Domestic Uses of Wood
Wood energy can be used in various forms depending on what it is needed for :
- CharcoalCharcoal is carbon produced by the pyrolysis of wood in the absence of oxygen... can be used to cook food. The heating value of this fuelFuel is any solid, liquid or gaseous substance or material that can be combined with an oxidant... is twice as high as that of dry wood.
- Dry conifer wood (spruce, pine, and fir) or softwood (larch, willow and poplar) is used for conventional bread ovens. This wood burns quickly and releases a lot of heatIn the field of statistical thermodynamics today, heat refers to the transfer of the thermal agitation of the particles making up matter... .
- Hardwood logs (oak, beech, ash, hornbeam, walnut, and chestnut) are used for heating purposes in open fireplaces and fireplace inserts, stoves and boilers. Stoves and boilers can also burn chips (shredded branches) or pellets (compressed sawdust).
- Chips (shredded branches) or pellets (compressed sawdust) are increasingly available in large supermarkets.
Whatever form the wood is in, it is important to keep it away from damp areas and ensure that the stove is working correctly.(2)
7 million the number of French households that use wood for heating
In the industrial sector, wood energy has many applications, including firing ceramics, tiles or bricks, heating or drying products, and producing hot water or steam, for example for dry cleaning. This fuel is also sometimes used to generate powerIn physics, power is the amount of energy supplied by a system per unit time. In simpler terms, power can be viewed as energy output... . Water is heated in a large wood-fired boiler and the resulting steam drives a turbine that generates an electric current. Worldwide, wood is the main biomass resource used to produce electricityForm of energy resulting from the movement of charged particles (electrons) through a conductor... .
Which Wood to Use as Fuel
In developing countries, 2.5 billion people rely solely on wood for heating, lighting and cooking.
Wood used as a source of thermal energy (see Close-Up: "Wood-Fired Heating Practical Information") has several origins:
- Wood and residue from forestry operations, such as branches, crowns and stumps.
- Farm waste.
- Waste from the wood industry, such as bark, sawdust, shavings and other waste from sawmills, paper mills, and pallet, furniture and timber product factories.
- Untreated used or scrap wood packaging, such as crates, cases and pallets. Particleboard, which has been treated and often bears traces of glue, paint or varnish, is not used as it can release corrosive and toxic emissions when burned.