Definitions, Conventions and
Conversion Factors Applied
DEFINITIONS, CONVENTIONS AND CONVERSION FACTORS
Fuelwood : Primary wood combusted as it is for satisfying energy needs (final sectorial use or even for electricity generation where relevant). This definition corresponds to the one adopted by UWET where all wood sources, that have not undergone any energy conversion process, are considered. Woodfuels could be used under different forms:
· Direct : Fuelwood that is collected/removed directly from the fields for the specific energy purposes;
· Indirect : Fuelwood that does not come directly from the fields, i.e. the wood was removed for other purposes (e.g. Industrial, conditioning, traditional industries, etc.) and the Fuelwood is rather a by-product (e.g. Fuelwood that comes from the different kinds of wood residues produced by the wood industry units);
· Recovered (or recycled) : Fuelwood that is recovered from furniture, and different wood items after their normal utilization life.
Charcoal : Energy item that is derived from Fuelwood and used to satisfying final sectorial energy demand or even for electricity generation where relevant.
Carbonization Ratio (Tons Wood/1 Ton Charcoal) : 1 Ton of charcoal is derived from 6 CUM of Fuelwood according to FAO assumptions (which means 4.35 tons of wood for 1 ton of charcoal). However, this estimate is not likely to be generalized for the case of Africa where the carbonization efficiency is substantially lower. In fact, the Carbonization Ratio is rather ranging from 5 to 12.6 tons of wood for 1 ton of charcoal, according to different statistical sources consulted.
For sources other than FAO the general Carbonization Ratio assumed = 6. However, when mentioned, the specific ratio of each data source was applied. The list of the specific ratios are included in the introductory section of each of the data source related appendix.
Black Liquor : a specific wood-derived fuel (indirect woodfuel) that is recovered and used as fuel from the manufacture of paper. The derived energy comes from the lignin removed from the wood pulp.
Woodfuels : include all categories of primary or converted wood used for energy : Fuelwood, Charcoal and Black liquor.
Final Energy (or woodfuel) : Energy that is quantified at the final user level (consumer). The calorific values and conversion factors used are those assumed by the FAO, i.e. :
¬ 1 kg of Fuelwood = 13.8 Mj
¬ 1 kg of Charcoal = 30.8 Mj
¬ Wood Density : 1 CUM of Wood = 0.725 tons
¬ Black Liquor : 1 Ton chemical Pulp produced Equivalent to 2.27 CUM Wood
¬ 1 CUM of Wood = 10 000 GJ
¬ TOE (Ton of Oil Equivalent) = 41.868 x 10-3 TJ
¬ MJ : Mega Joule = 106 Joules
¬ GJ : Giga Joule = 109 Joules
¬ TJ : Tera Joule = 1012 Joules
¬ PJ : Peta Joule : = 1015 Joules
Primary Energy : Energy that is quantified at the primary user level before any transformation process. For example, the primary Woodfuel consumption is quantified in energy terms by adding the following items : Fuelwood + Charcoal (in terms of Fuelwood equivalent using the carbonization ratio) + Black Liquor (in terms of Woodfuel equivalent using the conversion ratio mentioned above)