This paper examines and reviews currently used terminology and definitions for woodfuels and other biofuels used in FAO, and in other major databases on biomass-based energy sources. It also proposes ways to improve the methodology for the definition, classification, compilation and presentation of biofuel data and information using the Unified Bioenergy Terminology (UBET).
UBET is compared with current terminology and classification systems, notably the FAO system for gathering woodfuel statistics for its FAOSTAT database which is the source of the woodfuel statistics provided in FAO Forest Products Yearbook, the International Energy Agency (IEA), EUROSTAT, and the United Nations Standard International Trade Classification (SITC). The main departure from these systems is that UBET stresses the supply and demand aspects of biofuels, with particular attention to wood-based fuels, as major commodities to satisfy end user requirements.
Biofuels are classified as direct, indirect or recovered biofuels, according to their "journey" from supply to the end user. The inclusion of agrofuels, such as bagasse, straw, stalks, etc. and the use of municipal by-products (sludge, municipal wastes, sludge gas, etc.) represents an innovation in the UWET classification proposal . The document offers basic working definitions and outlines the measurement parameters and units taken into account. Biofuel conversion and accounting factors are provided in order to obtain the energy worth of a mass or volume flow of a particular biofuel.
UWET was prepared jointly and discussed with many institutions, with the common objective of assessing properly the amount of energy produced from biofuels and of facilitating the exchange of bioenergy databases among national and international organizations. Certainly this new terminology and set of definitions are not a panacea for solving the many problems associated with wood energy data, but are intended as a first and essential step towards their improvement.
In the future, more attention will be given to the definition of different types of agrofuels. This is an area that has so far received limited attention - not only regarding the terminology used but also in the development of improved data bases.