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Production side, supply

Common groups

Users side, demand examples

4.2.1. Woodfuels

Table 6. Woodfuel types from different supply sources


Supply side (sources)

(wood energy vectors)

Direct Woodfuels

Indirect Woodfuels

Recovered Woodfuels









Black liquor




Other (methanol, ethanol, pyrolitic gas)






land farms

sugar/starch crops

crops planted basically for the production of ethanol (ethyl alcohol) as a fuel mainly used in transport (on its own or blended with gasoline). Ethanol can be produced by the fermentation of glucose derived from sugar-bearing plants (like sugar-cane) or starchy materials after hydrolysis

oil crops

oleaginous plants (e.g. sunflower, rape, etc.) planted for direct energy use of vegetable oil extracted, or as raw material for further conversion into a diesel substitute, using transesterification processes

other energy crops

include plants and specialized crops more recently considered for energy use, such as: elephant grass (Miscanthus), cordgrass and galinggale (Spartina spp. and Cyperus longus), giant reed (Arundo donax) and reed canary grass (Phalaris arundinacea)

marine farms


fresh water farms

water hyacinths

4.2.3 Municipal by-products

This refers to biomass by-products produced by the urban population and comprise two types: solid municipal by-products, and gas/liquid municipal by-products produced in cities and villages.

Solid municipal biofuels: comprises by-products produced by the residential, commercial, industrial, public and tertiary sectors that are collected by local authorities for disposal in a central location, where they are generally incinerated (combusted directly) to produce heat and/or power. Hospital waste is also included in this category.

Gas/liquid municipal biofuels: biofuels derived principally from the anaerobic fermentation (biogas) of solid and liquid municipal wastes which may be land-fill gas or sewage sludge gas.

For easy reference, Table 8 provides brief definitions of the main terms adopted. Table 9 provides some examples for the biofuel classification proposed.

Table 8: Proposed Definition of Biofuel Classifications

1st level

2nd level

Brief definition


Direct Woodfuels

Wood from forests, shrubs and other trees used as fuel

Indirect Woodfuels

Mainly solid biofuels produced from wood processing activities

Recovered Woodfuels

Wood used directly or indirectly as fuel, derived from socio-economic activities outside the forest sector

Wood-based fuels

Mainly liquid and gaseous biofuels produced from woody biomass


Fuel crops

Growing plants for the production of biofuels

Agricultural by-products

Mainly by-products from crop harvesting and other kinds of by-products from agricultural activities left in the field

Animal by-products

Primarily excreta from cattle, horses, pigs and poultry

Agro-industrial by-products

Several kinds of biomass materials produced chiefly in food and fibre processing industries, such as bagasse and rice husks

Municipal by-products

Several kinds solid and liquid municipal biomass materials produced in urban societies

Table 9: Examples for proposed biofuel classification


classification for statistics

whole tree chips

direct, primary, solid, woodfuel

black liquor

indirect, primary, liquid, wood-based fuel

charcoal briquette

direct (or indirect or recovered) secondary, solid, wood-based fuel

demolition wood

recovered, primary, solid, woodfuel

plant methyl ester (PME)

secondary, liquid agrofuel from fuel crops

ethanol from bagasse

secondary, liquid agrofuel from agricultural by-product

biogas from MSW digestion

secondary gaseous municipal by-product fuel

3 An overview on bioenergy production and consumption is given in the bioenergy balance.

4 FAO Forestry web site. Forestry Terminology: URL

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