Hall / Barnard / Moss Biomass for Energy in the Developing Countries

Current Role, Potential, Problems, Prospects
1. Auflage 2013
ISBN: 978-1-4831-3862-6
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 254 Seiten

Biomass for Energy in the Developing Countries: Current Role, Potential, Problems, Prospects focuses on biomass energy and its importance to developing countries. This book outlines the reality that supply can no longer meet the demand of this form of energy. This fact is particularly observed in the rising price of oil, which is a prime source of energy for developing countries. Relative to this, a need to look for indigenous energy sources is urgent to sustain development in these countries. This book emphasizes that biomass energy utilization differs among developing countries, which shows the variance in energy needs. This text also notes that the pattern of biomass energy use in such countries is related to agriculture and also has cultural, economic, and social linkages. Biomass energy is also considered an important aspect in rural development and as a replacement for petroleum products. With the impending shortage of biomass energy, schemes are now being developed to sustain the use of this energy in household and industry settings, which is emphasized in the development of equipment considered energy efficient. People who are concerned with the development and implementation of programs aimed at conserving biomass energy and in the search of alternative energy can use this book as a reference.

Autoren/Hrsg.

Hall, D. O.

Barnard, G. W.

Moss, P. A.

Leseproben

Chapter 2

The Present Role of Biomass Energy

Publisher Summary

This chapter provides an overview of the present role of biomass energy in the developing countries. It presents an approximation of the global magnitude of biomass energy use and the available quantitative data on biomass energy usage. The chapter describes the characteristics of biomass utilization—what types of biomass are used for fuel in the developing countries, how these fuels are collected, and how they are used and the functions that they perform. It also presents a summary of the available quantitative data on biomass energy usage. The pattern and extent of biomass energy utilization varies significantly between developing countries reflecting differences in energy needs, fuel-use practices, and the relative availability and cost of biomass fuels compared to other fuel forms. Within countries, energy use patterns are also far from uniform. They commonly show regional variations as well as difference between income groups. Use of biomass for cooking and heating in the home is the largest application of biomass energy. In many developing countries, the availability of crop residues for energy purposes is severely limited by the fact that these residues are also used extensively for animal feed as well as for various other purposes.

In assessing the future prospects for biomass energy in the developing countries it is important to understand the major role that biomass energy already has in these countries. As a background to the discussion of biomass development options that is presented subsequently, this chapter provides an outline of the present role of biomass energy in the developing countries. An approximation of the global magnitude of biomass energy use is presented initially. This is followed by a general description, in qualitative terms, of the characteristics of biomass utilisation – what types of biomass are used for fuel in the developing countries; how these fuels are collected; how they are used and the functions that they perform. Finally, a summary is presented of the available quantitative data on biomass energy usage.

2.1 Global Perspective

The role that biomass plays in the current world energy supply has only recently been fully recognised. Although estimates are still only crude – due to the non-commercial nature of most biomass fuels and the resulting problems in measuring their consumption – energy from biomass probably accounts for as much as one seventh of total world energy consumption. (This is approximately four times the amount which is provided by hydroelectricity and nuclear power combined.) This startlingly high figure arises from the fact that the main biomass fuel forms – wood and charcoal – are the primary cooking and heating fuels for more than half of the world’s population.

The role of biomass in the developing countries is particularly striking. In many countries, as is described later, biomass provides more than half of total energy needs. In extreme cases this reliance can be as great as 95%. The global distribution of biomass energy use between the developed and developing countries is shown diagrammatically in Figure 2.1. Whereas biomass represents only a minor component in the energy budget of developed countries, on average it provides for approximately 43% of the energy use of developing countries. The majority of this use occurs in rural areas, where about 70% of the population lives, and where biomass fuels are often the only energy source which is both available and affordable to the mass of the population.

Figure 2.1 Global Distribution of Energy Use (1978) Source : Commercial Energy – UN; “Energy Supplies 1970–78” Biomass Energy – Calculated assuming annual per capita consumption of biomass fuels in developing countries equals 15 GJ for rural populations (2.1 billion people) and 8 GJ for urban dwellers (0.9 billion people). Figures for developed countries taken from Parikh (reference 58).

2.2 Characteristics of Present Biomass Energy Utilisation

The main forms of biomass used for energy purposes in the developing countries are the so-called ‘traditional fuels’ – wood, charcoal, crop residues and anumal dung. These are mainkind’s oldest energy sources and their collection and use remains an integral part of the fabric of life within the developing countries, particularly in the rural sector.

The pattern and extent of biomass energy utilisation varies significantly between developing countries, reflecting differences in energy needs, fuel-use practices and the relative availability and cost of biomass fuels compared to other fuel forms. Within countries, energy use patterns are also far from uniform. They commonly show regional variations as well as difference between income groups. The types of biomass used can also vary at different times of the year, due to seasonal fluctuations in biomass availability.

The overall pattern of biomass energy use in developing countries is extremely complex, being closely linked to agricultural practices as well as various cultural, social and economic factors. Only in a very few cases have the micro-level features of biomass use been characterised in detail. On the basis of the sketchy knowledge that is available at present, however, the main characteristics of biomass energy use in the developing countries in its main applications – for household uses, agriculture and industry – are summarised below.

a) Household Energy

Use of biomass for cooking and heating in the home is the largest application of biomass energy. Wood is the commonest biomass fuel used, followed by charcoal but dung, crop residues and vegetable wastes are also important in many countries where wood is not readily available. These fuels are burnt on open fires or in simple stoves of various designs, usually with very low efficiency (the nature of cooking stoves is discussed in more detail in subsequent sections). The use of commercial fuels (kerosene, bottled gas, electricity) for cooking and room heating in the developing countries, although it has been increasing over the years, is still relatively rare and is usually limited to the more affluent sectors of the population, largely in urban areas. (It is interesting to note that traditional fuels, especially charcoal, are sometimes preferred to the more modern fuel forms for certain types of cooking, owing to the flavour they impart to the food.)

In rural areas biomass fuels are generally collected on a ‘free good’ basis, usually by women and children within the community. The types of biomass used and the effort required to gather them depends on availability. Where population pressures are not too severe, fuelwood can usually still be found relatively easily – from wooded land, scrub and isolated trees that exist near to the home. If wood is scarce, on the other hand, people have to be less discriminating the the types of wood they use and they are forced to travel further afield to collect it; increasing the ‘social cost’ of the fuel significantly. In some regions of the world this can mean journeys of half a day or more, representing a very major burden on the rural community.56

Conversion of wood to charcoal tends to be more common when transportation distances are long. The conversion methods used are generally fairly basic, employing either covered wood-piles or simple earthen kilns, both of which are very inefficient. Charcoal making also occurs in some cases where wood is being used locally, such as in Thailand and Senegal, due to a preference for charcoal over other cooking fuels. In most cases this implies a greater overall wood consumption because although charcoal stoves may be two to three times as efficient as wood stoves, the initial charcoal making process commonly involves energy losses of as much as 80% of the original energy content of the wood.

In cases where adequate wood supplies cannot easily be found and commercial fuels are either too expensive or are unobtainable, crop residues are often employed for fuel. These include stalks and husks from various grain crops, cotton and nut wastes, and sugar cane bagasse. In some countries, notably Bangladesh, these residues are the major source of fuel for domestic uses.16 More commonly, however, their use is restricted to the times of the year when they are readily available (following harvest, for example).

In many developing countries the availability of crop residues for energy purposes is severely limited by the fact that these residues are also used extensively for animal feed, as well as for various other purposes (such as thatching). Under such circumstances, often the only other locally available fuels are animal dung – and to a lesser extent, vegetable wastes. Dried dung cakes are an important source of fuel in parts of India and Bangladesh, for example, as well as in the sparsely forested Andean regions of Bolivia and Peru.89 The burning of animal dung has also been reported in some Sahelian countries, parts of the Transkei in South Africa,8 and in Ethiopia and Iraq.50 On a worldwide basis, it has been estimated that between 500 million and one billion people rely on animal dung for a portion of their domestic energy needs.

In urban areas...