This study examines the present role of biomass in the world's energy supply and calculates the potential for future biomass energy provision into the next century. It looks at examples of present biomass production and conversion to both modern and traditional fuels. Environmental effects of biomass use are examined on the global scale, considering health and sustainable production practices. Policy issues are discussed at the local and international level.
Biomass1 can be converted into modern energy carriers through mature and novel conversion technologies and thus, has the potential to be a significant new source of energy into the next century. Biomass is a flexible feedstock capable of conversion into solid, liquid and gaseous fuels which can substitute for fossil-based fuels at relatively small scales of investment. It will also continue to meet its important traditional roles i.e., cooking, heat, light, construction, etc. in the rural and urban sectors of developing countries. Many benefits may accrue from significantly increasing the use of modern forms of biomass energy. These may include the reduction of CO2 emissions to the atmosphere if advanced biomass conversion technologies are used as a substitute fossil fuel-based technologies. Furthermore, the adoption of advanced biomass energy conversion systems may well be less costly than equivalent advanced fossil fuel-based systems. {Williams & Larson, 1993} A recent synthesis by Johansson et al., {1993} estimate that biomass could provide about one fifth of electrical power and two fifths of direct fuel use by 2050.
1 Biomass is defined as all forms of plant-derived matter (terrestrial and aquatic) other than that which has been fossilised. This includes: dedicated agricultural and forest products e.g. fuelwood, sugarcane, rape seed, etc, agricultural and forestry residues, animal wastes- both dung and abattoir-derived, municipal solid wastes (MSW) including sewage, and peat where its use can be demonstrated to be renewable.
Problems certainly exist and some of the new conversion technologies are still to be demonstrated. Also, without proper monitoring there is the potential for the unsustainable exploitation of the existing biomass sources, often at the expense of natural forests and woodlands. Biomass energy systems can be land and labour intensive and can thus significantly affect the local environment and socio-economic climate.
Biomass production is essentially modular and decentralised, providing substantial rural employment (both skilled and unskilled). It does not demand large capital investments which characterise other non-fossil based energies such as hydro-electricity and nuclear power.
Modern conversion technologies and management practices can provide non-polluting and convenient biomass-derived fuels at prices which range from highly-competitive to near-market. Technologies under development suggests there will be a long term requirement for biomass which can provide environmentally friendly energy from the local to the global level.
Sustainable biomass production requires detailed local-level planning and the central involvement of local people. Also, a long term commitment to implementation and monitoring is necessary if the multiple benefits of biomass energy are to be permanently realised. Such a commitment should be based on a realistic assessment of present biomass use and the potential size of the biomass resource. If these conditions are met then there is no need for conflict between future food and energy needs. In fact, if an integrated approach to the production of food and fuel is adopted, there could be benefits both from increased food and bioenergy production.
We estimate from detailed country studies that biomass currently provides about 14% of global primary energy consumption and could in the future theoretically supply the equivalent to about 3 times the present global energy demand. This scenario allows for increases in cropland area for food production by 2025. (see Tables 1 & 2). Based on these assumptions, there is a long-term practical potential for both Africa and Latin America to become net exporters of biomass fuels such as alcohols and hydrogen.
Uncertainties exist, but the effects of climate change may be beneficial to biomass growth through the synergistic effects of increased levels of carbon dioxide in the atmosphere in combination with increasing rainfall and temperatures. With the environmental incentives to shift away from fossil-based fuels to CO2-neutral and low sulphur fuels, biomass energy should be seen as an entrepreneurial opportunity for producing environmentally acceptable and socially beneficial fuels.
