Fig. 2:

Table 3:    (In million tons)

 Source: M.Eusuf , Business Meet on Renewable Energy, 1999.

All the units of each type may not use only biomass energy sources. As for example, most tea processing units now use natural gas and many of the brick burning units use coal. Similarly shaft power, whenever needed, is obtained by using engines fired with biomass fuels, diesel engines, electric motors or from human and animal power.

There is lack of reliable information on the consumption of fuel by the industries but it may be stated that most small and medium rural industries use biomass fuel. While it is not possible how the total biomass fuel available in the country is used, amount of biomass fuel as used per unit product in some of the rural industries for cookstoves, ovens, kilns and furnaces are given in the following table

5.         Urban Household

In urban households, kerosene or electricity is used for lighting. Natural gas, LPG, electricity, kerosene and biomass fuels are used for cooking. In areas without natural gas and electricity, biomass (mainly higher quality fuel wood) is used to meet the household cooking needs. A recent BEPP urban household survey estimated that per capita consumption of biomass fuel is 319 kg / person / year (assuming 6.9 persons per household)

6.         Types of Biomass Energy End-use Technologies.

6.1              Households:

The traditional cook stoves are usually mud-built cylinder with three slightly raised stands on which utensils rest. The efficiency of the biomass used for fuel is between 5-10%, spreading pollution and greenhouse gases. Because of scarcity of freely available biomass (cow dung, jute sticks and leaves) that used to be collected, firewood has to be procured which is affecting the wood mass from limited homestead or even natural forests.     

6.2              Improved Cook stoves:

BCSIR has been carrying out research on improved stoves for a long time. Their improved household stove is claimed to save 40 – 60% fuel compared to traditional ones. There are about 3,00,000 improved stoves in operation, but they are not being regularly used. A strong drive is required to use improved household stoves. Forest Department is planning to build one million stoves for households living in the forest area. Government has also similar plans for other rural households.

As for improved cook stoves and also ovens, kilns and furnaces, we are going to hear from Dr. Hasan about its development and commercial prospect.

6.3              Biogas Plant:

Biogas is a gaseous fuel produced by the anaerobic fermentation of animal waste and other non ligneous cellulose materials (including agricultural waste, municipal waste, kitchen waste, and industrial waste. It is a mixture mainly of methane and carbon-di-oxide. It is produced in a closed container called digester and can be used directly by pipeline distribution or by keeping the gas in a metal container for later use (to run internal combustion engine or other uses). Table 9a and 9b show constituents of biogas and sources of biogas with potential availability.

Table 9a: Constituents of Biogas.

(Source: Aktaruzzaman, 1999.)

Table 9b:  Source of Biogas and Potential Availability.

(Source:Aktaruzzaman, 1999),  * author’s addition

More than 25,000 biogas plants (mostly of fixed dome type) mostly by BCSIR using mainly cow dung have been installed for households. Institutional and Commercial biogas plants have now been constructed by various agencies especially LGED, using cow dung, poultry dropping or even human excreta. There is a huge potential for biogas production from municipal and other industrial wastes (e.g. press mud). Recently the Netherlands Development Corporation is starting a national programme to set up 36450 biogas plants by 2009. GTZ in collaboration with BCAS has recently completed a feasibility study to promote biogas plants from commercial poultry farms (now numbering 116,250).Their findings, as presented by Dr. Khalequzzaman in a meeting of experts stakeholders, as shown in Table 10.

          Table 10:

It appears that poultry biogas plants of moderate and larger sizes are financially viable. For farms of moderate sizes, only heat application is preferable. Larger size farms could also produce electricity. Such studies should be undertaken for commercial biogas plants based on livestock and other wastes. There is a huge potential for commercial biogas plant for other uses. Mr. Akbar Ali, an ingenious entrepreneur runs a 30 tons capacity re-rolling mill, partly with the help of biogas produced not only by cow dung (collected from the area ) and poultry droppings from his own farm ( 35000 birds ) saving fuel cost of the second part of his mill( ingot to rod) by about Tk 5 lakh per month. Photo 3  shows cow dung being poured into biogas plants in shamim re-rolling mill in Jessore and Photos 4 shows fire emitted from the pipe which carries the gas to the furnace.   

Biogas plants have not only the advantage of improved efficiency and multidimensional use, the GHG emissions will also be reduced and organic fertilizers will be available as a by product.

6.4       Briquettes:

Briquette is a block of condensed biomass, with increased volumetric calorific value, for use as fuel. Such briquettes are comparable to woody biomass (with high ash content) and quite study & stable with long self life. Different types of biomass like rice straw / rice husk, sawdust, wheat husk, jute stick and bagasse can be used, but at present, mostly rice husk is used as raw material.

After successful researches on briquette production, they are now available commercially. Most of them are heated-die screw-press type. They can density 75 – 100 kg of biomass per hour, operated with 15, 20 or 25 horsepower electric motors. Alternative methods are being attempted to avoid electricity or reduce the cost of production. New production methods have already reduced the cost of machine to $800 (from initial $2500) and more than 1000 such machines are in operation in the country.

KUET, with support from AIT, Bangkok, has developed improved biomass briquetting systems and stoves and disseminated some of them with success. The general conclusion made by Prof. Md. N.A. Nawsher Ali Moral is given in Table 11.

                    Table 11:

Recently BRRI has made briquettes from rice husk and use them as fuel for heating purposes in their laboratory and got 20% better efficiency. They plan to use them in various rice mills for parboiling.

6.5       Biomass Gasification and Bio-fuel

There has been no work on biomass gasification in Bangladesh. A demonstration bio-gasification plant of 200 KW based on rice husk is being set up by LGED in Dinajpur. Another 250 KW commercial power plant, also based on rice husk, is planned to be set up by a private entrepreneur in Kapasia, with assistance from IDCOL.

As for bio-fuel, a joint venture between a local company (NITOL MOTORS) and two Singapore firms have recently been signed to invest $ 4.5 million to manufacture 12,000 liters of ethanol from molasses from the Sugar Mills of North Bengal. It will be mixed with normal petrol / octane in the ratio of 23:77 to be produce ‘gasohol’ to run motor vehicles. The price of ‘gasohol’ will be 20 – 30% lower than conventional petrol.

Mr. S. Nathak will speak on prospects of biomass gasification (and bio-fuel) in Bangladesh.