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Background

Nepal has, in theory, a viable hydropower potential of 40 000 MW of energy, but to date it uses less than 1% of this potential because of the high cost of generation. From Table 1 it can be seen that most of the energy demand in Nepal is still met through traditional energy sources such as fuelwood - 67.9%, agricultural residues - 14.9%, and animal dung - 8.1%. If we look at the energy consumption per sector for the same year, 91.3% of the total energy is consumed by households, out of which 72.4% is met by fuelwood alone (Figure 1). Figure 2 shows the typical household energy end uses for the rural hill areas of the Western Development Region of the country. Most of the energy (about 80%) is used for cooking, including the preparation of animal feed.

Table 1: Energy consumption by fuel type and sector
Type of energyFuelwoodElectricityPetroleum productsAnimal dungAgricultural wasteCoal
Percent (%)67.90.97.28.114.91.0
SectorResidentialAgricultureTransportCommercialIndustry
Percent (%)91.30.73.21.43.4

Total energy consumption per annum - 271 million GJ
Source: Water and Energy Commission report (Financial Year 1992/93)

It is obvious that traditional sources, especially fuelwood, which form an important part of the energy supply, cause deforestation and serious ecological and environmental degradation in the country.
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Figure 2: Typical household energy end uses in rural hill areas (%)

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Figure 1: Household energy consumption (%)
!!Alternatives to fuelwood
In its search for alternatives, the country has introduced several alternative energy sources and technologies such as biogas, microhydro, kerosene, liquefied petroleum gas (LPG), improved cooking stoves, solar/wind technologies, briquettes, etc. An analysis of the alternatives (Elite Consultants) has shown that most of the technologies/energy sources:
  • are comparatively expensive (biogas, microhydro, solar, wind technologies, LPG, kerosene)
  • require additional investment (for purchase of stoves, equipment, accessories, installation)
  • require huge subsidies for promotion (biogas, microhydro, improved cooking stoves, solar technologies)
  • have limitations (biogas - climatic, and kerosene/LPG -huge amount of foreign currency for import)
  • cannot serve as a direct substitute for fuelwood.

It is interesting to compare the energy efficiency and effective energy output per rupee of several energy types. The comparison is shown in Table 2.

This table clearly shows that efficiency is highest for electricity and gas, but (rice husk) briquettes are the most cost-effective fuel. Briquettes have some drawbacks such as increasing prices, combustion problems etc., but with some technical interventions, the modification of products, or by raw material substitution, they could provide an alternative to fuelwood for domestic cooking purposes. Most of the government and donor-led economic development plans have accorded priority and financial support to various alternatives such as biogas, cooking stoves, microhydro, etc., but promotion of briquettes and briquetting technologies is still lacking. Considering the technical and economical characteristics shown in Table 2, it can be seen that briquettes, with good government support, could very well serve as a possible alternative to fuelwood.

Table 2: Cost comparison of different energy sources
NoType of energyUnit quantityPrice (RS/unit)GJ/unitGJ/RSEfficiency (%)Effective GJ/R5
1Fuelwood1 kg4.420.01670.0038170.0006
2Electricity1 kWh4.000.00360.0009760.0007
3Gas1 kg21.130.04520.0021700.0015
4Kerosene1 litre9.000.03650.0041480.0020
5Briquette1 kg3.400.02230.0065370.0024

Source: Water and Energy Commission report

Biobriquettes

Biomass briquettes of low density, manually prepared from animal dung and biomass (straw, jute sticks, etc.), have been used in rural Nepal for generations. With the introduction of densification technologies from Taiwan, biomass briquettes (rice husk and saw dust) have been produced using extrusion technology. They were a success when they were first introduced, as the raw materials - rice husk and sawdust -were cheap. However, more recently, these raw materials have found direct industrial use in boilers, causing a major price increase, making briquette production and briquettes expensive.

A joint research project, the National Research and Development Centre for Alternate Energy (NRDCforAE) was initiated in 1992 with technical assistance from the Japan International Cooperation Agency (JICA) in the Royal Nepal Academy of Science and Technology (RONAST). The NRDCforAE addressed the problem of biobriquettes for the first time in the country, taking into consideration the cheaply available biomass materials such as sugarcane bagasse, banmara, pine needles, etc. Next, the project introduced the concept of biocoal, which is a composite fuel made of biomass and coal with an optimum composition of 25% biomass and 75% coal or lignite.

Comparative tests of different biobriquettes

Different biomass briquettes (EBB, EBM) and biocoal briquettes (BC), shown in Figure 3, produced experimentally at the NRDCforAE of RONAST and the Hokkaido Institute of Japan(HIRI), were tested in the laboratory and in field trials for cooking purposes. Some of the test results are given below.
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Figure 3: Different types of biobriquette
!!!Laboratory tests
Fuels used for testing:
FWFuelwood
BC-17Biocoal (Jumlepani Ghorahi coal 75%, Lumbini bagasse 25%)
BC-19Biocoal (Jumlepani Ghorahi coal 40%, Lignite 40%, Lumbini bagasse 20%)
EBB-1Briquette (rice husk)
EBM-3Extruded type briquette (with Abidhara coal 20%, Chitwan rice husk 80%)
EBM-9Extruded type briquette (with Abidhara coal 40%, Nawalparasi rice husk 58%, Chovar lime 2%)
C-8Coal (Indian coal)
B-12Cowdung (Kathmandu)


Different fuels were used to boil water, using similar conditions for each test. Laboratory tests were conducted using an appropriate stove to boil water using a kilogram of each fuel. The amount of evaporated water and the corresponding calorific values of the different fuels are given in Figure 4.

By measuring the amount of water which could be evaporated by each type of fuel it could be seen that different briquettes (BC-17, EBB-1, EBM-3) gave better results under the same conditions (evaporating more water) than could be achieved using the same amount of fuelwood (FW) as shown in Figure 4.
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Figure 4: Calorific values of various fuels and the amount of water evaporated by each fuel
!!!Field tests
The same fuels were used for field tests at Mugling, a road junction some 160 kms south west of Kathmandu Valley through which all road transport coming and going out of Kathmandu passes. Mugling and its surroundings has over 100 tea-stalls and restaurants and alone consumes about 16 tonnes of fuelwood daily.
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Figure 5: Cooking tests at the Rupsi Hotel

The tests were performed at the Rupsi Hotel/restaurant (Figure 5) by cooking:
  • mansuli rice - 1kg
  • rahar dal - 0.25kg
  • potatoes - 0.5kg
which is the normal quantity of food cooked for a family of 5 persons (2 adults and 3 children). The results of the tests are given in Figure 6.
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Figure 6: Comparison of different fuels for cooking

While cooking food for 5 persons almost all of the briquettes (BC-17, BC-19, EBB-1 AND EBM-9) show better results than fuel-wood: either in terms of the total cooking time (BC-17, EBM-9) or in terms of the amount of fuel consumed (BC-17, BC-19, EBM-9). The shortest total cooking time used BC-17 briquettes (64 minutes) and only 1.54 kg of the fuel was required, whereas for the same result, it took almost 3 kgs (double the amount) of fuelwood and 85 minute of cooking time. The time required to cook each individual item varies with the fuel used. A general observation is that, using briquettes, the cooking time for rice is always less than when using fuelwood.

Furthermore, the combustion tests showed that the biobriquettes burn with a more uniform flame and at a higher temperature than fuelwood. The biobriquettes. particularly biocoal, were found to be easier to ignite, they lasted longer and burnt with very little smoke or harmful exhaust gases. The duration of combustion for all the biobriquettes - biomass, biocoal and even cowdung was longer than for fuelwood.

Conclusions

  • Biobriquettes can boil more water than fuelwood under similar conditions
  • Biobriquettes take less time to cook the same amount of foodstuffs than other fuels
  • Only half the weight of bio-coal briquettes (BC-17) was required compared to fuel-wood to achieve the same results
  • Biocoal briquettes are easier to ignite and last for a longer period of time than fuelwood
  • The combustion of biocoal briquettes is smooth with very little generation of smoke and harmful exhaust gases. A

References

  1. Energy Synopsis report, Nepal 1992/93, Water energy Commission Secretariat 1994, Kathmandu Nepal
  2. Final Report on Biomass Activity (Summary), July 1995, NRDCforAE, RONAST, Kathmandu, Nepal
  3. Perspective Energy Plan, Supporting Document No. 3., Alternative Energy Assessment, Water energy Commission Secretariat 1994, Kathmandu, Nepal
  4. Biobriquettes - A Potential Alternative to Fuelwood, A Study Report for JICA/RONAST on Alternative Energy Development Project, July 1995, Elite Consultants P. Ltd, Kathmandu, Nepal

Acknowledgments

The author would like to thank all the NRDCforAE team members, particularly Mr. Keiichi Yoshida, Mr. Toshino Chino, long term JICA experts and RONAST colleagues Mr. Rishi Shah, Mr. Gyani Ratna Shakya, Dr. Y.B. Chettri for their kind cooperation and assistance in making this publication possible.

Further Readings

More information on bio-briquettes available at: http://www.bgrcnn.net/resources.html
Last edited by Miriam Hansen .
Page last modified on Friday October 1, 2010 10:21:53 GMT.
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