Badrul Imam
In spite of being insignificant in volume, the availability of biogas to very large number of rural people and to very remote areas make the technology very suitable and effective. True, commercially produced pipeline natural gas plays and will continue to play vital role in the industrialization and urbanization of the country, but this gas will not reach the remote village households any time soon, if at all! In that respect there is no alternative to biogas for the millions of villagers
Bangladesh produces about 1100 million cubic feet of natural gas daily and imports about three million tons of crude oil and petroleum product per year. These are referred to as commercial energy and provide for 35 per cent of the total energy consumed in the country. These commercial energies are mainly used in urban based industries to generate electricity, to run industrial and commercial units and to supply domestic households in major cities and towns. Ironically, these commercial energies are mostly out of bound of the vast majority of the rural people of the country. So where does the nation's energy balance leave the vast majority of the rural population? It is the biomass energy source that is available to the latter and it consists of fuel wood, leaves, agricultural residues, cow dung and other organic wastes. These are referred to as non commercial energy and actually provide for the remaining 65 per cent of the total energy consumed in the country.
About 80 per cent of the total population of the country or about 100 million people live in rural area. The non-commercial biomass energy sources (fuelwood, cow dung, agricultural waste etc), these people traditionally use are inefficient and poorly managed. For generations, their energy technology base has remained inefficient and primitive. It is estimated that only about 19 per cent of the country's total population have electricity, 4 per cent have natural gas connection in the households. In the rural area only 5 per cent of the population use kerosene as fuel.
Commercially produced natural gas is playing a vital role in the industrialization of the country. With increasing industrialization and urbanization the demand for natural gas will continue to grow. It is said that the country would require about 13.6 Tcf of gas upto 2020, about 26.7 tcf upto 2030, and about 62 tcf upto 2050. With natural gas as the single significant commercial energy resource available in the country, it appears that the present reserve of 11.6 tcf will not run beyond 2020. For this reason, most of the experts opine against the idea of gas export from the country.
The above gas demand scenario is, however, based on the projected requirement of urban based power plants, fertilizer factories, industrial and commercial units to be built in future. This projection does not envisage providing natural gas directly to the vast majority of the rural people. This is not practical for two reasons, i) it is not possible to build gas pipe line infrastructure to connect thousands of villages throughout the country, ii) even if that were possible, the rural population would not have the purchasing power to use pipe line gas in their households.
The above situation leave the rural population to rely on the traditional biomass sources for household supply of energy. This is however not only a case with Bangladesh, but many other developing nations like India, Pakistan, Nepal, Sri Lanka, Thailand, China etc. Over the last few decades there have been renewed interests and initiatives by many developing countries to innovate new and improved biomass energy technologies whereby the biomass energy sources can be used more efficiently and managed more scientifically. The most popular and widely used of these technologies has been the biogas technology in which biomass (cow dung, poultry dropping, agricultural residue etc) is converted into biogas. The biogas is supplied to households for use in cooking in a similar way natural gas is used. In addition, biogas may be used to light houses as does the petromax. Biogas can also be used to run small generator to produce electricity for running electrical household appliances like TV, electric light, fridge etc.
Quiet little villages of Jaintiapur: Abudur Rashid with a family of ten, runs a grocery shop for a living in the quiet little village of Mokambari in Jaintiapur thana in Sylhet. While most of the families in the village manage fuel wood, dried cow dung, leaves and argi waste as fuel for cooking, Abdur Rashid runs a biogas plant in his house. The biogas, supplied from the plant to the kitchen is used to run a two burner cooker where the gas burns with clean blue flame free of smoke or ash, much the same way a Dhaka city household burns Titas gas. Mr Rashid informed that he installed the biogas plant three years ago. The plant runs on cow dung collected from five cows, which (the dung) is fed into an underground chamber through a hole on the ground surface. That is all he has to do in the morning and the gas automatically flows through a half inch pipe to the kitchen.
In the nearby village of Naljuri, a primary school teacher Nazrul Islam installed his biogas plant five months ago. His family of six is very satisfied with the biogas plant which not only supplies gas to the kitchen, but because the plant is fed with cow dung and other agri waste, the environment of the house it kept clean. Like Abdur Rashid his 100 cubic ft biogas plant cost Tk.14000, of which he received a subsidy of Tk.7500 from the government. An one burner cooker will use 10 cubic feet of gas per hour, so a 100 cubic feet biogas plant, producing 100 cubic feet of gas a day can run a single burner for 10 hours each day, enough for all the cooking his family needs.
Both the above families are fortunate to be included in biogas project of Science Laboratory, Dhaka (Bangladesh Council of Industrial and Scientific Research). The project was originally initiated in 1995 for 5 years to install 5000 biogas plants thoughout the country, informed Mr. Rashed Ismail, Deputy Assistant Biogas Engineer, responsible for supervising biogas installation programe in Jaintia area. A second phase of the project started in 2001 for four more years during which time 20,000 more biogas plants are supposed to be installed throughout the country. There are 128 biogas engineers working at the field level throughout Bangladesh to familiarise the technology and supervise the installation of biogas plant. Considering the level of interest among the rural people and the benefit this brings to individual household, there should be more help from government and non government organization toward these projects.
Kazi Akhtaruzzaman, Director of the Biogas project of the Science Laboratory at Dhaka, emphatically pointed out the potential this project has to upgrade the social and economic status and standard of living of the rural population. It is, however, unfortunate that we cannot give enough manpower assistance nor the required financial support to meet the countrywide demand existing at the moment. There is lack of understanding as well as commitment on part of the high ups in the administration about this kind of micro level project. Bangladesh remains far behind the neighbouring countries in developing biogas as apparent from the fact that the number of biogas plant installed is about 30 lac in India, 70 lac in China, 70 thousand in Nepal and only about 8000 in Bangladesh.
Ideal technology for rural Bangladesh: Biogas plant is built with simple technology and uses raw material easily available with the rural households -- mostly cow dung. Biogas is a kind of gas generated when biomass i.e cow dung or other animal dung or biodegradable organic masses are stored in underground chamber in an anaerobic condition (absence of oxygen). It is a kind of anaerobic bacteria that produces the biogas from the organic debris. The composition of biogas is mainly methane (65%) with lesser amount of carbon di oxide (30-35%) and trace hydrogen and nitrogen. It is a colourless gas and burns in similar way as natural gas (it actually burns at 800 degree centigrade compared to natural gas which burns at 1000 degree centigrade, both suitable for cooking and any other household application). A biogas plant consists of a brick made underground chamber about 10 feet in height connected to a smaller surface feeding chamber on one side and a debris outlet chamber on the other side. Cow dung or other bimass material with water (in 1:1 ratio) are fed once a day into the underground chamber from the surface and biogas is generated and accumulated at the top part of the chamber. The gas is tapped by inserting a rubber pipe and supplied to kitchen or other places in the house. After producing gas, the cow dung is moved to the outlet chamber under the gas pressure and incoming new biomass materials and is deposited in a pit as a very good quality fertilizer ready to use in the field.
In Bangladesh 40 million tons of fuelwood is used in rural areas as cooking fuel each year. This destroy our forest and has negative impact on weather, land and environment. Also, as other biomasses like leaves, cow dung and agricultural residues are burnt as cooking fuel, these can no more help as a natural fertilizer as part of the cycle that keeps the balance in the ecosystem. In all the above counts, use of biogas technology will bring about benefits to the environment and the people. It certainly upgrades an age-old inefficient and poor energy use practice into a more efficient and scientific one.
Only a small volume of gas is produced by biogas plant. A 100 cft plant produces 100 cft gas per day. The presently installed 8000 biogas plants in the country cumulatively produces 0.8 million cubic feet of gas per day. Supposing, the present target of installing 20,000 biogas plant be achieved by the year 2004, the volume of biogas that will then be produced will be two million cubic feet per day. This is peanut compared to 1100 million cubic feet of natural gas that the country commercially produces from gas fields at present. The fact remains that in spite of being insignificant in volume, the availability of biogas to very large number of rural people and to very remote areas make the technology very suitable and effective. True, commercially produced pipeline natural gas plays and will continue to play vital role in the industrialization and urbanization of the country, but this gas will not reach the remote village households any time soon, if at all! In that respect there is no alternative to biogas for the millions of villagers like Abdur Rashid and Nazrul Islam.
Dr. Badrul Imam is Professor, Geology Department, Dhaka University.
Source: The Daily Star, Dhaka, April 25, 2002