L.A. Horta Nogueira, M.A. Trossero, L. Couto and L.C. Couto
L.A. Horta Nogueira is a participant in the FAO Academic Programme. He is with the Escola Federal de Engenharia de Itajubá, Brazil.
M.A. Trossero is Senior Forestry Officer (Wood Energy), Forest Products Division, FAO, Rome.
L. Couto and L.C. Couto are with the Universidade Federal de Viçosa, Brazil.
Wood fuels and industrial raw material: competition or complimentarily?
Forests and trees provide a significant share of global energy requirements, both in developing and developed countries. Besides their traditional utilization as fuel for cooking (the primary energy source for more than two billion people), the use of wood fuels as a modern and environmentally suitable source of energy for industry and power generation is expanding (FAO, 1995). For instance, wood fuels at present account for more than 16 percent of total energy supply in Sweden, Finland, Austria and other European Union countries (FAO, 1997). Recent international fore and agreements have highlighted the environmental advantages of bioenergy utilization, mainly with regard to the CO2 cycle and greenhouse gas emission mitigation, creating an additional thrust for wood energy expansion (UN, 1997).
Harvested timber in Viet Nam used for both fuel and packing crates
However, although wood resources are renewable they are not infinite, and the increasing demand on forests and trees for energy and also for other wood and non-wood products (including but not limited to timber, wood for pulp and paper production) raises the question of the sustainability of long-term supply. The scope of this article is to consider briefly the relationship of wood fibre for energy supplies, both in non-industrial and industrial use, with overall fibre supply for industry. This question will be addressed in greater depth in a future issue of Unasylva.
A general flow of wood products derived from forest and non-forest land for energy and non-energy uses is shown in the Figure. In considering this diagram, it is important to understand that bioenergy systems are site-specific and complex processes that enable energy users to be supplied with different types and qualities of wood fuel derived from various sources and prepared with various technologies available in the market. As well as being derived from various sources (natural and planted forests, trees outside forests), wood fuels can be derived from byproducts of forest industries (sawmills, particle board plants, etc.). The various primary and secondary types of wood fuels derived from these different sources reach a disparate group of users (households, industrial and commercial concerns) in different areas (rural and urban) via numerous channels. This intrinsic complexity is relevant and should be properly considered when analysing the relationship of wood fuel and non-energy industrial uses of wood fibre.
Use of wood residues as fuel in a particle board factory in Indonesia
FIGURE - Types and flow of wood
The Table below presents a basic set of proposed definitions of wood fuels. The prime motivation behind this particular wood fuel classification is recognition of the basic site where biomass production occurs. It is proposed that these definitions should be used by United Nations and other international organizations involved in the collection, collation and presentation of bioenergy data.
TABLE. Proposed classification of wood fuels
|
Wood fuels |
Brief definition |
|
Direct wood fuels |
Wood used directly or indirectly as fuel, produced for energy purposes |
|
Indirect wood fuels |
Mainly solid biofuels produced from wood processing activities |
|
Recovered wood fuels |
Wood used directly or indirectly as fuel, derived from socio-economic activities outside the forest sector |
|
Wood-derived fuels |
Mainly liquid and gaseous biofuels produced in forest activities and the wood industry |
Taking into account the above-mentioned considerations, a number of observations can be made regarding the flow of woody raw material for industrial energy purposes and those for other uses.
Competition between industrial and non-industrial wood fuel users
There is almost no competition for wood fuel resources between the two main types of consumer (households and industry). These groups tend to be physically isolated from each other and to obtain their raw material from different sources. For instance, fuelwood for cooking and home heating in rural areas - where most people live in developing countries - is supplied primarily from dead trees, pruning and other woody wastes. Demand in this sector, which is a major user of wood fuels, is of relatively low intensity and scattered over large areas where wood fuels are collected individually. In general terms, the wood fuel needs of this sector are in balance with the supply sources.
On the other hand, household and commercial users (bakeries, restaurants, street food vendors) of wood fuels from fuels large urban centres are characterized by their high demand for wood fuels derived from a relatively small area. This type of use can lead to serious wood fuel shortages and depletion of forests. Similar situations can be found in areas where there is a large concentration of industrial wood fuel use, such as for brick making, lime burning and pottery production. Here again, shortages of fuel supplies can arise if their use is not properly organized.
In areas with a combination of urban and pert-urban wood fuel users for both household and commercial activities, consideration needs to be given to the competition that forms between the different users. Resulting conflicts can become especially serious in arid and semi-arid areas. For example, in parts of the Sudan, local bread making industries are highly resented by household fuelwood users because they use trucks and motorized equipment to remove comparatively large quantities of wood for energy (J. Ball, personal communication, 1998).
A special case is the use of wood fuels by large industrial users (e.g. large pulp and paper industries, iron and steel makers, cement factories, heat and power generation plants). The energy needs of these industries demand structured and well-managed production, transport and storage systems and even the preprocessing of wood. In most cases, they have their own established wood supply sources.. Sporadic conflicts do exist but could be resolved by local market forces: raising prices, diversifying supply sources, planting more trees, etc.
Small-scale industrial use of fuel-wood: brick making in Brazil
Competition between energy and non-energy uses of wood
What is even more important is that there is generally little competition for wood fuel resources between energy and non-energy end uses. Virtually all fuelwood for household energy use is collected from natural forest. Where these forests are managed for industrial use, local fuelwood users generally co-exist with industrial users. The wood collected by local people to meet household energy requirements tends to be small, dead wood or small debris left behind after commercial harvesting. Most local fuelwood users have neither the desire nor the tools to harvest the larger living resources that are commercially valuable.
As a corollary, the significant (although poorly recognized) use of wood processing by-products is not in conflict with non-energy uses. Where these products can be used for other purposes, for example agglomerated board production, the decision to use these materials as fuel or as raw material for finished products depends largely on the relative value of the finished product and alternative sources of energy (fossil fuels, biomass from other sources, etc.).
One clearly unsustainable method of generating wood fuels for industry is their provision as a by-product of land clearing operations associated with the transformation of forest into agricultural land. However, the use of this biomass as wood fuel is better than simply burning it as slash and, in most cases, the wood is too heterogeneous in nature to carry commercial value for non-energy uses.
Nevertheless, in certain areas where the demand for wood fuels continues to grow to meet the increasing need for industrial energy (especially where energy users are seeking alternatives to fossil fuels to reduce their greenhouse gas emissions), competition can be expected in the future between energy and non-energy uses of wood supplies.
The Brazilian case
Brazil is one of the countries where woody biomass, particularly wood fuels, is one of the most important renewable sources of energy, not only to meet household energy needs but also those of the industrial and commercial sectors.
About 11 percent of the total primary energy consumption of Brazil is provided by biomass derived from forests, woodlands and trees, corresponding to 98.9 million m3 in 1996 (Government of Brazil, 1997). On the other hand, the country's wood production for non-energy uses is also very important, reaching more than 84 million m3 in the same year (in 1996, consumption by the wood pulp and paper industry alone was approximately 30 million m3 and is expected to increase by 15 percent over the next three years (FAO, 1996).
Usually, conflicts among the different users are not apparent on a general scale. However, in certain geographical areas and during some periods of the year there is competition for wood raw material among energy and industrial consumers. For example, this conflict occurs between the pulp and paper industries, iron makers and cement factories in certain areas of the State of Minas Gerais where such users dispute the control of some forest resources.
However, these conflicts seem resolvable; there has been a rapid expansion of silvicultural activities to provide more wood fuel and/or round wood, and this has been encouraged by price increases and other market stimuli. Today, about half of the total 6 million ha of planted forests in Brazil are for energy production.
There are many examples of the multiple use of forests products for energy and non-energy uses in Brazil and other countries. However, one of the most interesting cases is an electricity generation plant that is being built in the State of Bahia (Brazil). When completed in 1999, this plant will have a capacity of 30 MW and will generate electricity in a very efficient way, using an advanced Biomass Integrated Gasification/Gas Turbine system (Carpentieri, 1997). The plant will be fuelled half with logging residues from local paper and pulp plants and half with wood fuels harvested from a very short rotation eucalyptus plantation. The expected cost of the energy to be produced ranges from US$38 to US$66/MWh, confirming the economic and operational feasibility of biomass use in large-scale electricity generation (FAO, 1996).
Overall, wood fuels for industrial use play a complementary role with biofuels for household use, and competition is unlikely to arise between them. The large and increasing demand for wood energy uses by large wood-based industries as well as other industries (e.g. iron and steel makers) and other medium and small-scale users for heat and power generation does not appear to conflict with systems supplying fuelwood for household consumption. Moreover, there is generally no competition between energy and non-energy uses of wood.
However, in areas where industrial modernization and a high level of economic development have resulted in greater energy needs, future conflicts can be expected among different wood energy and non-energy users. Therefore, there is an urgent need for the development of sustainable wood supply systems, the improved management of existing forests and the establishment of additional forested area where such systems are feasible end economically justifiable.
ANFPC. 1997. Relatório Estatístico. São Paulo, Brazil, Associação Nacional de Fabricantes de Papel e Celulose.
Carpentieri, E. 1997. Project SIGAME. Renewable Energy in the Americas Conference, Rio de Janeiro.
FAO. 1995. Forests, fuels and future (Wood energy for a sustainable development). Forestry Topics Report No. 5. Rome.
FAO. 1996. Pulp and paper capacities 1995-2000. Rome.
FAO. 1997. The role of wood energy in Europe and OECD. Wood Energy Today for Tomorrow, regional study. Working Paper FOPW/97/1. Rome.
Government of Brazil. 1997. National Energy Balance. Brasilia, Ministry of Mines and Energy.
UN. 1997. Kyoto Protocol to the Framework Convention on Climate Change. Kyoto. Japan.
