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Wood energy terminology, information, statistics and standards

D. Thrän

Daniela Thrän is Project Manager at the Institute for Energy and Environment, Leipzig, Germany.

FAO’s effort to develop a unified terminology is a first step towards harmonizing wood energy data.

Bioenergy systems include many phases from the production, preparation and transport of raw materials to their conversion into fuel, distribution to consumers and utilization for energy production. A proper understanding of such complex systems requires clear information at all levels. It is increasingly recognized that improved and more detailed bioenergy data, adequately disaggregated, are necessary for planning the sustainable production and utilization of biomass for household as well as commercial and industrial uses. Consistent definitions, units and conversion factors are needed to enable comparison, aggregation and exchange of information.

Clear definitions for bioenergy sources, trade forms (e.g. briquettes, chips) and properties (e.g. density, particle size) are needed, for example, to advance biofuel trading, which is still rather undeveloped. A unified bioenergy terminology and specifications, well adapted to practical needs (as for the different types of gasoline or fuel oil), can contribute to the optimization of biofuel products with respect to certain qualities (e.g. particle size and moisture content of wood chips), leading to cost reductions and assisting the development of biofuel markets.

FAO data on wood supply and demand are a reference for many institutions. To improve the process of collecting, organizing and presenting wood energy data, FAO (2001) has developed a Unified Wood Energy Terminology, in close cooperation with the European Standardization Committee, which will be drafting more than 20 European standards on solid biofuels during the next two years.

The aim was to create a suitable framework for identifying the amount and type of bioenergy flowing from different supply sources to meet end-users’ needs. Its development required a conceptual view of bioenergy systems, showing the flow of biofuels to satisfy demand. Thus the fuel or product used to transport energy is the basic parameter to be accounted and classified.

The unified bioenergy terminology defines three types of biofuel, distinguished according to the primary production process: woodfuels, agrofuels and municipal by-products (see Figure). On the supply (production) side, the groupings clearly identify the origin of biofuels. On the demand (product) side, the groupings distinguish different types of unprocessed and processed fuels which can be used for heat, electricity and power generation.

Certainly the new terminology is not a panacea for the many problems associated with bioenergy statistics and trade, but it is a first and essential step towards improvement. By assisting the exchange of information, it should help governments and institutions address the problems of bioenergy utilization more efficiently through policy instruments, development projects and activities and investments. The next step is to promote the use of the terminology through publications, training and dissemination activities, and through its use in FAO’s Wood Energy Information System database.

Biofuel classification scheme


FAO. 2001. Unified Wood Energy Terminology. Working document FOPW/01/05. Rome. Available on the Internet:

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