case studies final lbriquettes machine
TRANSCRIPT
Renewable Energy Technology Promotion in Asia: Case Studies from Six Asian Countries
S. Kumar S. C. Bhattacharya
Dipal C. Barua Trinh Q. Dung
Arnold R. ElepañoMohan B. Gewali
Muhammad Ibrahim Md. Nawsher Ali Moral
Dinesh Sharma Pham K. Toan
Based on the activities carried out under
Renewable Energy Technologies in Asia: A Regional Research and Dissemination Programme
Funded by
Swedish International Development Cooperation Agency
Coordinated by
Asian Institute of Technology
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Renewable Energy Technology Promotion in Asia: Case Studies from Six Asian Countries
PUBLISHED BY Regional Energy Resources Information Center (RERIC) Energy Field of Study Asian Institute of Technology P.O. Box 4, Klong Luang Pathumthani 12120 Thailand
E-mail: [email protected] Website: http://www.serd.ait.ac.th/reric/
ISBN: 974-8202-65-6
Copyright © 2005, Asian Institute of Technology, Thailand.
No part of this publication may be reproduced by any means, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the written permission of the publisher.
Printed in Thailand.
DISCLAIMERNeither the Swedish International Development Cooperation Agency (Sida) nor the Asian Institute of Technology (AIT) makes any warranty, expressed or implied, or assumes any legal liability for the accuracy or completeness of any information herein provided. References herein to any apparatus, product, trademark or manufacturer do not constitute or imply its endorsement, recommendation or favouring by Sida or AIT.
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ForewordEconomic growth, industrialization and growing population in the developing countries of Asia contribute to a rapidly growing demand for energy in the region while global environmental concerns call for limiting use of fossil fuels. Renewable Energy Technologies (RETs) present a viable option of meeting the growing energy demand, especially in remote and rural areas. However, before full commercialization of RETs can be achieved, many barriers need to be overcome. Apart from adaptive technological improvements, this also calls for appropriate financial mechanisms, institutional/research capacity enhancement and public awareness through demonstration and dissemination. The Governments of Asian countries have a key role to play in promotion of RETs through appropriate policy interventions. To address these issues ‘Renewable Energy Technologies in Asia: A Regional Research and Dissemination Programme’ was launched in 1997 by the Swedish International Development Cooperation Agency (Sida) and the Asian Institute of Technology (AIT). The programme involved thirteen institutes from Bangladesh, Cambodia, Nepal, Lao PDR, the Philippines and Vietnam.
The programme activities carried out in the thirteen participating institutes and at AIT included adaptive research, demonstration of RETs systems, dissemination of research outcomes to the stakeholders and capacity building. The wide range of activities and achievements of the RETs in Asia programme in the six countries have been presented in six booklets:
1. Technology Packages: Solar, Biomass and Hybrid Dryers 2. Technology Packages: Screw-press Briquetting Machines and Briquette-
fired Stoves 3. Technology Packages: Low-Cost PV System Components 4. Demonstration and Monitoring of PV Systems: Lessons Learned 5. PV System Components: Technology Fact Sheets 6. Renewable Energy Technology Promotion in Asia: Case Studies from Six
Asian Countries
The information presented in the above booklets is expected to be useful to a number of stakeholder groups, including those who are involved in renewable energy development projects in the Asian region, business community, policy personnel, NGOs and research institutions.
Dr. Gity BehravanAugust 2005 Senior Research Advisor, Sida
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PrefaceIt is increasingly becoming evident that current pattern of rising conventional energy consumption cannot be sustained in the future due to two reasons: the environmental consequences of heavy dependence on fossil fuels, particularly climate change, and the depletion of fossil fuels. Therefore, at present, a near consensus appears to be emerging that renewable energy technologies need to be promoted if global energy supplies are to be placed on an environmentally sustainable path.
Despite the efforts of various government institutions, universities, NGOs and international development organizations, renewable energy technologies are yet to make a substantial contribution towards betterment of the quality of life in the developing countries. To find wider acceptance, it is very important to make sure that renewable energy solutions are accessible, affordable and appropriate. Research and development institutes in developing countries have a vital role to play in the development, local adaptation and promotion of renewable energy technologies. These institutes have much to gain through regional networking with similar institutes in other countries by sharing experience and carrying out joint coordinated research.
In this background, the Swedish International Development Cooperation Agency (Sida) sponsored a regional programme entitled “Renewable Energy Technologies in Asia: A Regional Research and Dissemination Programme (RETs in Asia)”. The programme, executed during 1997-2004, was coordinated by the Asian Institute of Technology (AIT) and involved thirteen research institutions from six Asian countries: Bangladesh, Cambodia, Lao PDR, Nepal, the Philippines and Vietnam. Three technologies/applications were identified for research, promotion and dissemination: solar photovoltaics, renewable energy based drying and biomass briquetting/briquette-fired stoves.
Six books have been prepared to disseminate the findings of the RETs in Asia programme. This document presents details of few case studies carried out under the RETs in Asia programme. The cases detail the need to consider the design and development, technical performance, users’ feedback and key factors to success. The information presented is expected to be useful to those who are involved in developing renewable energy projects in the Asian region.
We are grateful to the Swedish International Development Cooperation Agency (Sida) for providing financial assistance for carrying out the activities under the programme. We are also thankful to Dr. Gity Behravan for her continuous support and guidance during the implementation period.
Prof. S. KumarAugust 2005 RETs in Asia Coordinator
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RETs in Asia Project Team Swedish International Development Cooperation Agency (Sida)Dr. Gity Behravan – Senior Research Advisor
Principal InvestigatorsProf. S.C. Bhattacharya – Energy Field of Study, Asian Institute of Technology, (until December 2004)
Prof. S. Kumar, Energy Field of Study, Asian Institute of Technology, P.O. Box 4, Klong Luang, Pathumthani 12120, Thailand. Tel: (+66 2) 524 5410, Fax: +66 2 524 5439, Email: [email protected]
National Research Institute (NRI) Team LeadersBangladesh
Mr. Dipal C. Barua, Managing Director, Grameen Shakti (GS), Grameen Bank Bhaban, Mirpur - 2, Dhaka - 1216, Bangladesh. Tel: (+88 02) 9004081, Fax: (+88 02) 803559, E-mail: [email protected]
Prof. Muhammad Ibrahim, Executive Director, Centre for Mass Education in Science (CMES), House #828, Road #19, Dhanmondi Residential Area, Dhaka - 1209, Bangladesh. Tel: (+88 02) 811898, Fax: (+88 02) 803559, E-mail: [email protected]
Prof. Md. Nawsher Ali Moral, Mechanical Engineering Department, Khulna University of Engineering and Technology (KUET), Khulna 9203, Bangladesh. Tel: (+88 041) 774900, Fax: (+88 041) 774403, E-mail: [email protected]
CambodiaDr. Sat Samy, Under Secretary of State, Ministry of Industry, Mines and Energy (MIME), No. 47, Preah Norodom Blvd. Phnom Penh, Cambodia. Tel: (+85 5) 23 427 851, Fax: (+85 5) 23 990 602, E-mail: [email protected]
Dr. Phoeurng Sackona, Director, Cambodia Institute of Technology (ITC), Cambodia. Tel: (+85 5) 23 880 370, Fax: (+85 5) 23 880 369, E-mail: [email protected]
Lao PDR Dr. Phouvong Sayalath, Director, Technology Research Institute, Science, Technology and Environment Agency (STEA), P.O Box 2279, Vientiane, Lao PDR. Tel: (+85 6) 21 218 711, Fax: (+85 6) 21 213 472, E-mail: [email protected]
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NepalEr. Rishi K. B. Shah, Vice President, Centre for Renewable Energy (CRE), O. Box 589, Ga-2/717 Bag Bazaar, Kathmandu, Nepal. Tel: (+97 7) 1 248852, Fax: (+97 7) 1 226976, E-mail: [email protected]
Prof. Mohan Bikram Gewali, Executive Director, Research Centre for Applied Science & Technology (RECAST), Tribhuvan University, P. O. Box 1030, Kirtipur, Kathmandu, Nepal. Tel: (+97 7) 1 330348, Fax: (+97 7) 1 331303, E-mail: [email protected]
Mr. Gyani Ratna Shakya, Director, Technology Division, Royal Nepal Academy of Science and Technology (RONAST), P. O. Box 3323, Khumaltar, Patan, Nepal. Tel: (+97 7) 1 547719, Fax: (+97 7) 1 490190/ 547713, Email: [email protected]
Philippines Prof. Rowaldo R. del Mundo, Head of Solar Laboratory, University of the Philippines (UPERDFI), Diliman, Quezon City 1101, Philippines. Tel: (+63 2) 434 3661, Fax: (+63 2) 434 3660, E-mail: [email protected]
Dr. Arnold R. Elepaño, Associate Professor, College of Engineering and Agro-Industrial Technology, Institute of Agricultural Engineering, Division of Agricultural & Bio-Process Engineering, University of the Philippines Los Baños (UPLBFI), College, Laguna 4031, Philippines. Tel: (+63 49) 536 2650, Fax: (+63 49) 536 3291, Email: [email protected]
VietnamDr. Pham Khanh Toan, Director, Institute of Energy, Khuong Thuong - Dong Da, Hanoi, SR Vietnam. Tel: (+84 4) 8522453, Fax: (+84 4) 8523311, E-mail: [email protected]
Mr. Trinh Quang Dung, Director, Solar Laboratory, 01 Mac Dinh Chi St., 1 District Ho Chi Minh City, SR Vietnam. Tel: (+84 8) 8222 028, Fax: (+84 8) 8295 905, Email: [email protected]
Research Staff at AIT Mr. Mathias Augustus Leon – Energy Field of Study, AIT, Email: [email protected]
Mr. Md. Anisuzzaman – Energy Field of Study, AIT, Email: [email protected]
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Contents
iii Foreword
iv Preface
v RETs in Asia Project Team
vii Contents
1 Introduction
2 Rice Hull-Fed Drying System for Dried Mango Production
8 PV Battery Charging Station for Remote Communities
16 Solar Home System Demonstration for Dissemination
20 Productive Application of Photovoltaics: The Micro-Utility Approach
24 Local Production of PV Accessories
32 Biomass Briquetting Technology: Domestic and Small Industrial Applications
45 White LED Lamps: Replacing the Kerosene Lamps for Rural Home Lighting
49 Solar Dryers Offer Income Generation Opportunities
56 Conclusion
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1
IntroductionIn 1997, the Swedish International Development Cooperation Agency (Sida) launched a regional programme entitled “Renewable Energy Technologies in Asia: a Regional Research and Dissemination Programme (RETs in Asia)”. The objective of the programme was to promote few selected mature/nearly mature renewable energy technologies in Bangladesh, Cambodia, Lao PDR, Nepal, the Philippines and Vietnam. Thirteen national research institutes (NRIs) from these six countries participated in the regional programme. This regional programme was coordinated by the Asian Institute of Technology (AIT).
Activities of the programme involved adaptive research, development of technology packages and demonstration, capacity building of various stakeholders through workshops and training programme, and dissemination of programme activities to stakeholders in the participating countries, and throughout the region. Three renewable energy technologies were selected for promotion through the programme: photovoltaics, renewable energy-based drying and biomass briquetting/ briquette-fired stoves. Other activities of the programme included preparation of manuals and videos for the construction, operation and maintenance of RETs as well as development and demonstration of renewable energy systems.
This booklet presents eight case studies from six countries. The case studies have been identified based on the project activities and selected from all three technologies (e.g. biomass briquetting and briquette-fired stoves, renewable energy based drying system and solar photovoltaics). The case studies include among others, details of the description of the activity, technical features, cost details and key success factors. These are expected to be useful to the renewable energy project implementers, policy makers and other stake holders in the participating countries and other developing countries.
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Rice Hull-fed Drying System for Dried Mango Production
Mango is one of the major crops produced in the Philippines. The growing demand for dried mangoes has enticed local entrepreneurs to engage in business and development of a renewable-energy based drying system. This provided them an alternative for medium scale production of dried mangoes. A rice husk fuelled dryer is commercially being used for drying mangoes in the Nueva Vizcaya province of the Philippines. Sweetened mango slices with initial moisture content of 90% (wet basis) could be dried to 29% (wet basis) in 18 hours of continuous operation, at an average drying air temperature of 53ºC. The dryer produced dried mangoes whose quality (sensory and physical) was comparable to those available in the local market. The payback period of the dryer system is estimated to be less than four years, making the system a reliable and hygienic alternative to other drying methods.
Background Nueva Vizcaya is located in the north-central part of the Philippines. It has basically an agricultural economy. The province is a member of the Northern-Central Luzon (NCL) agriculture cluster which produced 477,251 metric tons (mt) out of the country’s total mango output of 995,886 metric tons (mt) in 2002. However, the producers face lower selling price of mangoes, and so local entrepreneurs find it necessary to engage in processing activities to increase their income. Figure 1: Map of Nueva Vizcaya
Source: http://www.dotpcvc.gov.ph/starstudded/wownuevaviz-MAP.html/
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Project details A rice hull-fuelled drying system was designed by the University of the Philippines Los Baños in coordination with the Asian Institute of Technology, Thailand. The dryer, designed for medium scale production of dried fruits and vegetables, suited the drying requirement of HOMM Food Products, a cooperative, situated in Nueva Vizcaya province. The dryer was installed in April 2002 and has since been regularly in use. The cooperative mainly uses it to dry mangoes, but pineapple and tamarind have also been dried.
Biomass was preferred for the dryer as rice hull is abundant in the Philippines and paddy processing generates an average of 1.5 million tons of rice hull a year. The average annual production of paddy in the province of Nueva Vizcaya is about 144,000 metric tons per year, generating about 28,800 metric tons of rice hull. The cooperative also owns a rice mill near the installation site, and hence the supply of rice hull is assured throughout the year. Utilizing rice hull would also be economically feasible as it is cheap, and in many occasions rice millers willingly offer them free, as disposing them otherwise is a problem for them.
Design of the Dryer The dryer operates by feeding rice hull into the combustion chamber for burning to produce heat inside the heat exchanger tubes. A centrifugal fan then forces the heated air to the drying chamber containing the product to be dried. A schematic diagram of the dryer is presented in Figure 3. An air distribution system in the drying chamber helps in the distribution of heated air. This is made up of concentric rings of different outer and inner diameters and it
Figure 2: Rice hull-fed drying system
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provides an almost uniform drying temperature at all locations of the drying chamber.
Figure 3: Schematic diagram of the dryer
The drying chamber houses two movable tray carts each having 26 trays. These trays can accommodate a total of 200 kilograms of sliced mangoes. At an average drying temperature of 53 C, the dryer can lower the moisture content of 90% (wet basis) down to 25% (wet basis) in 18 hours of continuous operation consuming 240 kilograms of rice hull. Twenty six kilograms of dried mangoes is produced when drying is complete.
Cost Details A simple cost analysis was done on the dryer, the details of which are presented below:
A. Initial Investment
The rice hull fed-drying system for mango drying costs P96,000 (US$ 1,715)1
B. Technical Assumptions
1 1 US$ 56 PhP (Philippine peso), October 2004
Drying chamber
ISOMETRIC VIEW
Recirculated air
Heated air
Hopper
Ambient air
Drying chamber
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The dryer will produce 200 batches per year. But, during the first year, the unit will operate at only half its capacity. The effective capacity of the dryer is 180 kg of sliced mango fruit per batch. With a recovery rate of 50%, 360 kg of sliced mango fruits per batch will be needed. The fuel feed rate is 13.20 kg of rice hull per hour. The dryer has a blower and motor capacity of about 1.5 kW.
C. Operating Expenses
The price of fresh mango fruit is P15.00 per kg. Preservatives: White sugar, 10% by weight of sliced mango costs about P30/kg. Sodium metabisulfite, 1 gram per 3 kg of sliced mango costs about P800 per kg. Confectioner sugar, 5% by weight of dried mango, costs about P55 per kg. Rice hull costs about P10 per sack (10 kg). Packaging material cost: P30/100 pieces. Labor cost for the operator and three fruit peelers: P300 each per day and P70 each per hour, respectively. Electricity tariff: P5 per kWh. Delivery cost: 3% of the sales revenue. Repair and maintenance: 8% of the total investment cost. Operating expenses assumed to increase by 5% every year starting on the 2nd year. Price of fresh mango is assumed to increase 5% every year starting on the second year. Depreciation is by straight-line method with a salvage value of 10% of the investment cost. Useful life is taken to be 5 years.
Yearly Expenses Fresh mangoes : Php 360,000.00 Sugar : Php 60,435.00 Sodium Metabisulfite : Php 4,800.00 Fuel : Php 23,760.00 Labor : Php 114,000.00 Electricity : Php 14,100.00 Packaging : Php 3,510.00 Delivery Cost : Php 28,080.00
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Depreciation : Php 16,200.00 Repairs and Maintenance : Php 7,680.00 Total Expenses : Php 632,565.00
(US$ 11,295.80)
D. Revenue
Recovery rate is 13% by weight of sliced mango fruit inclusive of confectioner sugar. Thus, the dryer produces 23.40 kg of dried mango fruit per batch of 360 kg of fresh mango.The selling price of dried mango fruit is P80 per 200-g pack. It is assumed that the price of dried mangoes will increase by 3% every year starting from the 2nd year.
Yearly Income Yearly income from the sale of dried mango: Php 936,000 (US$ 16,714)
Net profit Total net profit for the first year: Php 303,435 (US$ 5,418) Payback period: 3.63 years
Monitoring and Evaluation The University of the Philippines Los Baños monitored the dryer and modifications for the improvement of the design were made. An additional air duct to the air inlet eliminated the problem of ashes entering into the drying chamber.
Evaluation of dried mangoes produced using the drying system was carried out and it was found that the sensory and physical quality parameters of the dried mango are not significantly different from those available in the local market. The same is true as compared to those that are for the export market.
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Concluding Remarks The collaboration between HOMM Food Products and the University of the Philippines proved worthwhile as the company was in need of a dryer that it can operate inexpensively. This demonstration acted as an outdoor field evaluation and analyzes the applicability of the drying system developed.
The company has noted that this drying system is a financially viable option for production of dried mangoes, pineapple and tamarind. Also, the demonstration set-up has showed them ways to utilize rice hull from their rice mill which they had previously considered as a waste that was difficult to dispose.
The strategy of showcasing the technology through collaboration with HOMM Food Products proved effective in promoting the drying system. Through the collaboration, the positive impacts of a renewable energy-based drying technology could be highlighted as follows:
a. The rice hull-fed drying system offers a cheap and efficient method thus it is an attractive alternative to processing needs of small and medium farmers.
b. The drying system can provide employment in rural areas and help generate income.
c. Products with qualities at par with international standards can be produced.
For further details, please contact Dr. Arnold R. Elepaño Project Leader, RETs in Asia– Philippines, University of the Philippines Los Baños, College, Laguna, Philippines. Email: [email protected]
Related PublicationElepaño, A.R. and M.K.B. Gratuito. A Solar-Biomass Dryer for Pineapple. A paper presented by UPLB at the 51st Philippine Society of Agricultural Engineers Annual National Convention, 22-26 April 2001.
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PV Battery Charging Station for Remote Communities
The installation of a PV-based Battery Charging Station (BCS) has brought benefits to the people in remote rural communities. The BCS provides mainly lighting to the households. In addition, it can also supply power to the other establishments e.g. medicine storing facilities, entertainment and communication. This way, BCS provides multi-directional service to the rural community.
BackgroundPV based Battery Charging Station (BCS) is usually installed in a remote place where the grid electricity is not likely to reach in near future. The targeted users are low income group who cannot afford to purchase solar modules and have low energy requirement. The capacity of the station depends on the number of users to be served and their electricity needs. BCSs are also sometimes installed at locations where grid extension would reach within a short or a medium time period as the BCS can then be transferred to another suitable location.
The use of BCS is rather limited as compared to the solar home system. This is probably due to the fact that BCSs are not economic as a sole enterprise. However, experiences show that BCS can deliver power to the rural poor people who cannot afford solar home system. In addition, it can supply surplus power to the nearby establishments and earn extra revenue for the station. Experiences with recently implemented BCS in terms of technical and management issues are summarized below:
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Battery Charging Station Features
Vietnam Dong Dinh is a village located along the Tien River in Dong Thap province, in the Mekong Delta of Vietnam. This island, inhabited by about 600 families, has no road link with the mainland. Therefore, electricity and telecommunication network could not be established in the village.
A PV-based Battery Charging Station (BCS) was installed by Solar Lab in Dong Dinh village in May 1998 under the RETs in Asia programme. The BCS was built to provide battery charging facilities for forty five families/houses. In addition, it was designed to supply electricity to a cultural house (an entertainment room for the villagers), a health center and a post office. These houses were selected based on their proximity to the battery charging station, which was installed within the cultural house complex. The Department of Science and Technology (DOST) of the Dong Thap participated by building the infrastructure. The BCS was powered by an array of 1kWp PV modules. Box 1 lists the equipment installed and Figure 1 shows the schematic diagram of BCS installed in Vietnam.
Figure 1: Schematic diagram of BCS at Dong Dinh village
TV
PV modules
Controller
Inverter
Storage
Applications
Channels Batteries for the individual users
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The end users contributed to the installation by providing batteries (12V/ 20-70 Ah), lamps (12V/ 7W) and other fixtures. Solar Lab assisted them choose the appropriate size of the batteries and accessories. The BCS is used to recharge the battery of the houses, which can be utilized for approximately three days. It also recharges the battery bank of the cultural house. A specially designed controller diverts the power to the battery bank when each battery is fully charged.
The BCS provides the facility of charging the batteries which are used in 45 households. It also provides power to the cultural room, post office and health center. The charger-cum-controller charges the batteries for the households and when the batteries are fully charged, all the channels switch to the battery bank connected to the cultural room. The cultural room operates a lamp, cassette player, loud speaker, TV and VCR. The BCS charges a 400Ah battery bank, which is converted to 220AC by an inverter and fed to the appliances of cultural house at night time.
PV electricity has thus provided a unique facility for entertainment to the villagers by supplying power to the cultural room. It also supplies power to a radiotelephone to help the villagers communicate to the outside world. The health center operates a vaccine refrigerator powered by PV and serves as the only medical service in the island. Box 2 gives some specific features of BCS.
Lao PDR Phon Ngam Village in Savannakhet province is located about 120 km north of Savannakhet town. The major occupation of the people here is agriculture. The nearest grid electricity is about 30 km from the village. This village may not have access to the grid network in the near future.
A BCS was installed in August 1998. The objective of this system was to charge the battery brought by the local community. The users bring their batteries in specified days to the charging station and get them charged. The charging fee is about US¢ 50 per month. Figure 2 shows the BCS installed in Lao PDR.
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Box 1: Equipments installed in the PV BCS
VietnamCharging station
20 solar modules (50 Wp each) 1 Charge controller with 4 auto charging channels
Cultural house 1 battery bank (12V, 400 Ah) 1 inverter (500W) 10 lamps (15W each) and 2 lamps (20W) each 1 color TV (60W) 1 set of cassette player, amplifier and speaker (30W) 1 VCR (17W)
Health center 1 vaccine refrigerator (36W)
Post office 1 radio telephone (60W)
Lao PDR Charging station
20 solar modules (75 Wp each) 4 Charge controllers (10 charging channels)
Figure 2: Battery Charging Station installed in Lao PDR
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The BCS provides battery recharging facility to 40 users of the village. 13 of them have one 85Ah battery, one state-of-charge indicator (used to observe the charge level of the battery), one 20W lamp and one 14W B/W TV. The rest have one 85Ah battery, one LED and one 20W lamp. The users are suggested to operate the given loads for an operating period of 4 hours per day. Usually, the users are to get their battery charged every three days from the BCS.
Box 2: Features of the BCS
Dinh Dong village, Vietnam Total cost of establishment: US$ 13,0002.Monthly tariff/user: US$ 2 for a maximum of 10 charges.Daily tariff for cultural house: US$ 5. Charging capacity of the station: 200-300 batteries of 20Ah equivalent per month. Batteries charged: ~ 400 per month 80% of the users are within 1 km of the station while the rest are within 2 km.
Phon Ngam Village, Lao PDR Monthly tariff/user: US$ 2 for a maximum of 8 charges. Charging capacity of the station: 300 batteries of 85Ah equivalent per month.Batteries charged: ~ 250 per month 100% of the users are within 2 km.
Operation and Maintenance
Vietnam A technician was trained to operate the BCS, do troubleshooting and collect the dues from the users. Solar Lab does the maintenance work of all the installed equipment while a local NGO (Center for
2 1 US$ = 15,865 VND (July 2005)
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Applied Science and Technology) looks after the management issues. The users pay for the service and maintenance fees of their own systems. They also add distilled water to their batteries. Solar Lab shoulders the maintenance expenses of the charging station. Figure 3 shows a radio telephone powered by the PV array of BCS in Vietnam.
Lao PDR A “Users Committee” involving persons from the users has been formed to ensure proper operation and maintenance of the system. The committee consists of a Manager, an Assistant, an Accountant, a Cashier, two Technicians and four Members. The technicians have been trained to operate the system and carry out minor repairs. The users are also trained on maintenance of their system, especially the batteries. They add distilled water whenever necessary. The cashier maintains account under the supervision of the manager. The maintenance and repair costs are met from the revenue earned. The surplus is kept to recover the cost of the installation.
Figure 3: Radio telephone powered by BCS
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The maintenance cost of BCS in Lao PDR is about USD 50 per year and the average monthly operating cost for each user (including fees for battery charging, minor repair and maintenance of system, replacement of lamp, etc.) is about USD 1.2. Up to December 2004, batteries of five users were damaged. These users replaced their batteries by taking loan from the revenue earned by the station.
Concluding Remarks The following factors contributed to the success of the BCSs:
The appropriate site for the BCS and short distances of the users’ homes from the station, The possibility of grid electricity in the village is less likely to happen in the future, Connecting the cultural house and other fixed loads in Vietnam not only gives a constant revenue, but also helps the BCS to operate at full capacity, and The keen interest and assistance of the local authorities in making BCS work and the users’ participation in sharing the costs. Management of the station by local people who take care of the operation and maintenance of the station.
The forty five families in Vietnam and forty families in Lao PDR benefit from a better lighting system. In addition, it also provides them entertainment. The villagers of Dinh Dong village also avail the facilities at the cultural house. The vaccine refrigerator is used for storing medicines and the new telecommunication system connects the villagers of Dinh Dong to the outside world.
For further details, please contact Mr. Trinh Quang Dung Director, Solar Laboratory, 01 Mac Dinh Chi St, 01 District, Ho Chi Minh City, S. R. Vietnam. Email: [email protected]
Dr. Phouvong Sayalath Director, Technology Research Institute, Science, Technology and Environment Agency (STEA), P.O Box 2279, Vientiane, Lao PDR. E-mail: [email protected]
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Related Publications Dung, T.Q, Anisuzzaman, M., Kumar, S. and Bhattacharya, S.C. Demonstration of Multi-Purpose Battery Charging Station for Rural Electrification. Renewable Energy, 28, 2003, pp 2367-2378.
Muangnalad, P. Introducing PV in a Developing Country: The Case of Lao PDR. Proceeding of World Renewable Energy Congress. Brighton, UK, 2000, pp 871-874.
Dung, T.Q. Application of Photovoltaics in the Mekong Region. Proceedings of World Renewable Energy Congress. Brighton, UK, 2000, pp-1970-1973.
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Solar Home System Demonstration for Dissemination
Promotion of PV systems in developing countries faces financial, technical, institutional and policy barriers. Some of these barriers can be addressed by carrying out demonstrations. Choosing appropriate sites and users, providing suitable financial mechanisms and technical support, and creating awareness among the users can be an effective dissemination strategy to promote solar home systems.
BackgroundThe high initial cost of solar home systems (SHSs) and lack of awareness regarding its usefulness are among the major obstacles to the promotion of this technology application in the rural areas. Electricity is generally associated with grid and diesel generators and it is difficult for rural consumers to assess a PV system without actually observing it in operation. Moreover, their low-income level limits their ability to purchase a PV system. Grameen Shakti (GS) addressed these issues to promote PV systems in rural Bangladesh through demonstration coupled with innovative financing mechanisms and technical support.
Technical Features GS, formed in 1996, installed ten demonstration Solar Home Systems under the RETs in Asia programme in 1997, with the aim of disseminating this technology application in rural areas. Table 1 lists the details of demonstration systems installed by Grameen Shakti under this programme. Figure 1 shows an application of a system in an electronic repair shop.
The following criteria were considered in selecting the site and users:
Easy accessibility to the site by visitors who would like to observe the system,
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A minimum distance of 1 km of the site from the grid, Interest of users in meeting their electricity demand with PV technology, and The systems were designed to operate 3-4 hours/day with 3 days of autonomy.
Table 1: List of demonstration systems installed by Grameen Shakti under the RETs in Asia programme
System No. of Systems
Battery Controller Appliances Price
17Wp 3 12V, 50Ah 12V, 4A 2 lamps (6W each)
US$ 228
34Wp 3 12V, 71Ah 12V, 10A 2 lamps (6W each) and 1 B/W TV (14W)
US$ 333
50Wp 4 12V, 100Ah
12V, 10A 3 lamps (6W each) and 1 B/W TV (20W)
US$ 438
Figure 1: Use of PV electricity in an electronic repair shop
Financial Mechanism The demonstration also helped GS to identify suitable financial arrangements that their consumers would be willing to follow for the installation of the PV system. Under the first mechanism that GS introduced, the users had to pay 50% of the rural cost, while the remaining amount was to be paid in six monthly installments with a
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service charge of 8%. This scheme was not well received by the users. As a result, the initial down payment was reduced to 25% and the repayment period was extended to 2 years. The interest accrued from this scheme was limited to potential users of a certain income level. However, a plan of 15% down payment, and a three-year repayment period with a 12% service charge found more user acceptance. GS also offers 4% discount in case of cash purchases.
Effect of Demonstration
The demonstration provided a better understanding on solar home systems capabilities to users and visitors. The high number of inquiries and purchase of the systems in the areas where it was demonstrated indicate the effectiveness of demonstration as well as the level of awareness among the villagers.The financial mechanisms developed through this demonstration made the PV system affordable to users of different income groups.The demonstration facilitated on-site testing and evaluation of the solar home system performance in field conditions.
Box 1 presents the uses and effect of demonstration.
Box 1: Types of uses and effect of demonstration Types of uses
Household (lighting, entertainment and children’s education) Shops (extending working hours) Workshops (repairing electronic appliances)
Demonstration details Persons attending demonstration (up to Dec 2004): ~3,600 Installations in nearby areas3:
During Jan-Dec 1998: 74
During Jan-Dec 1999: 172
Up to June 2005: 3,593
3 The area refers to Tangail district which has an area of about 3424 sq. km and population 3,253,961.
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The demand of SHS has increased in rural areas of Bangladesh. Grameen Shakti has installed more than 43,000 SHSs up to June 2005 with a total installed capacity of 2.15 MWp. Currently, about 1,500 SHSs are being installed per month4.
Concluding Remarks The following are recommended for a successful demonstration:
The accessibility of the site, its communication facility, and distance from the electricity grid must be considered before choosing a location for demonstration, The systems should be designed to suit the needs of the users, Leaflets and brochures with detailed information about the systems and PV technology should be distributed to all potential users, Inquiries and suggestions made by the visitors should be recorded and followed up, and An appropriate financial mechanism should be developed taking into account the financial capacity of users. A survey on the preferences of prospective users maybe useful in formulating a more acceptable and affordable financial scheme.
For further details, please contact Mr. Dipal C. Barua Managing Director, Grameen Shakti, Grameen Bank Bhaban, Mirpur 2, Dhaka 1216, Bangladesh. Email: [email protected]
Related Publication Barua, D.C., Urmee, T.P., Kumar, S. and Bhattacharya, S.C. A Photovoltaic Solar Home System Dissemination Model. Progress in Photovoltaics Research and Application. 2001. pp. 313-322.
4 http://www.lged-rein.org/solar/solar_gs.htm
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Productive Application of Photovoltaics: The Micro-Utility Approach
Lack of electricity supply poses great hardships to the rural markets of developing countries. A PV-based electricity generation system with a reliable institutional arrangement, an effective financial mechanism and technical support can be an attractive option to supply electricity to such markets.
BackgroundManikganj bazaar5 is an important market in Ranirhat, Dinajpur district, about 400 km north of Dhaka, Bangladesh. There are about 40 shops in the bazaar, and their lighting needs are usually met by traditional kerosene lamps called “Kupi”. A PV-based electrification system for the shops was introduced by the Center for Mass Education in Science (CMES). The model was explained to the shop owners of Manikganj bazaar and the Bazaar Management Committee (BMC), who welcomed the idea of a PV-based micro-utility for the bazaar.
PV micro-utility system in a broad sense is similar to the Energy Service Company (ESCO) model where the users pay for service received. A number of PV modules are installed in a common place, near the market. Each user is connected with one or two lamps. The users do not own the system and pay a daily or monthly tariff for using the electricity. A technician is employed by the owner and is responsible for operation, maintenance and collection of tariff from the users.
Technical Features Box 1 lists the equipment installed for the system. Seven solar modules, each having a capacity of 50 Wp were divided into two sets
5 A rural market, similar to a growth center
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and installed in two locations of the bazaar. The batteries and the controllers of each set were placed close to the respective solar arrays. Twenty-four lamps were installed in twenty-one shops. These included grocery, restaurant, barber, pharmacy (Figure 1), village doctor's chamber and tea stall. A socket was also placed in the BMC’s room to operate a 14-inch Black & White TV (Figure 2). The system was designed to allow the lamps to function for 5 hours every evening. A trained technician operated and took care of the system and also collected the dues from the shops daily and deposited it in a bank.
Box 1: Equipment installed
The PV micro utility includes the following equipment/ components: 7 solar modules (50 Wp each) 7 batteries (12V, 100 Ah each) 7 Charge controllers (10 A each) 1 lamp (7 W each) in 18 shops, 2 lamps (7 W each) in 3 shops 1 socket for operating 1 B&W TV in BMC’s room.
MaintenanceSince the operation started in October 1999, the repair and maintenance works carried out were the replacement of the blackened lamps, repairing the connection of the charge controllers, replenishing the distilled water of batteries, etc. The technician was able to carry out minor repairs, while major repairs such as repairing the charge controllers, lamp circuits, etc. were handled by CMES personnel. Details of the financial features of the system are given in Box 2. Figure 1: Medicine shop using PV light
to extend its working hours
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User’s FeedbackFeedback from the users indicated that:
Having a local, full time technician led to a higher user satisfaction. The amount of light from the systems was sufficient. The pharmacy owner reported that the solar lighting made the market livelier and had improved his business. The tea-stall owner reported an increase in the number of his customers.The grocery shop owner also observed that the bright light of the PV-powered lamps attracted more customers to his shop. The restaurant owner reported an increase of his working hours.
Box 2: Financial details
Initial cost including site investigation, hardware and installation: US$ 3,030. Monthly repair and maintenance cost of the system: ~USD 2. Monthly personnel cost: ~ USD 14. Monthly tariff per lamp: ~USD 2.5. Simple payback period is about 5 years6.US$ 3.5 was taken as initial deposit from each user. CMES may forfeit this deposit in case of violation of agreement.
Concluding Remarks Soon after the installation of this system, demands for similar systems were noticed in nearby bazaars. CMES installed another nine such systems in next one year. The model was also tried in other parts of Bangladesh. The other PV operators e.g. Grameen Shakti have also adopted the model. Total installations of MU system in Bangladesh up to June 2005 is about 450. The success of the PV micro-utility is due to the following factors:
6 Based on a soft loan fund (with 2.5% interest, 5 years repayment period and, 5% inflation rate) and 10% discount rate of hardware.
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Initial survey to assess the financial capacity of the shop owners and thus the viability of the system, Increasing the understanding of the potential users about the capabilities and benefits of the system, Users’ awareness about the system’s constraints enabled them to take measures to shorten their operating time during extreme weather conditions, Agreement with BMC, which includes the terms and conditions of the service, maintenance procedure, payment methods and financial details of the users and security deposit, and Availability of a trained technician to take care of the system.
Figure 2: TV powered by micro utility
For further details, please contact Professor Muhammad IbrahimCenter for Mass Education in Science, House No. 828, Road No. 19, Dhanmondi R/A, Dhaka 1209, Bangladesh. Email: [email protected], [email protected]
Related Publication Ibrahim, M., Anisuzzaman, M., Kumar, S. and Bhattacharya, S.C. Demonstration of PV Micro-Utility System for Rural Electrification, Solar Energy, Vol. 72, No. 6, 2002, pp. 521-530.
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Local Production of PV Accessories
Development of PV accessories through adaptive research helps reduce the system’s cost through the use of locally available components. It also generates employment opportunities. Commercial production of the accessories was possible through continued research, testing and modification.
BackgroundLack of accessories of photovoltaic (PV) systems (e.g. Charge Controller, Lamp, DC to DC Converter, etc.) is one of the major hurdles faced during promotion of PV systems in developing countries. Imported accessories are not only expensive but also have several difficulties in their use. A reliable source of affordable system components was a major concern to the users of PV system. Therefore, development of inexpensive and reliable accessories, based on locally available resources, appeared to be an important requirement to promote photovoltaics in the region.
To develop low cost PV accessories adaptive research was carried out under the RETs in Asia programme. First, the need for development of the accessories was identified followed by design of the component. The designed components were first tested in the laboratory and then used in the field. Problems, if any, were identified and remedial measures taken. Box 1 summarizes the devices developed by Grameen Shakti (GS) in Bangladesh, Ministry of Industry, Mineral and Energy (MIME) in Cambodia and Solar Lab in Vietnam under the RETs in Asia programme. Figure 1 shows the sample inverter developed in Vietnam.
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Box 1: Devices developed by Grameen Shakti, MIME and Solar Lab under RETs in Asia programme
Accessories Specification
Grameen Shakti, Bangladesh Charge Controller Input: 12VDC
Capacity: 10A Display: Battery status Self consumption: 10mA
Ballast for DC fluorescent lamp
Input: 12VDC Power: 6W Operating frequency: 55kHz
DC to DC converter Input: 12VDC Output: 3, 6 & 9VDC Capacity: 1A Efficiency: 75%
MIME, CambodiaCharge controller Input: 12VDC
Capacity: 5A Display: Battery status Self consumption: 61mA
Solar Lab, Vietnam Adaptor for color TV Input: 12VDC
Output: 15/24/110 VDC Power: 100W
Inverter Input: 12VDC Output: 220VAC Power: 0.5-2 kW Type: True sine wave
Ballast for DC fluorescent lamp
Input: 12VDC Power: 9-11W Operating frequency: 80kHz
Charge controller Input: 12VDC Capacity: 15A Display: Battery status Self consumption: 8mA
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In Bangladesh, the developed accessories were used in the systems sold by GS to its customers and these were also supplied to the other organizations. In Vietnam, the systems were mostly used with the systems installed under different projects. Some devices were also sold to users.
Figure 1: Inverter developed in Vietnam
Status and Field Performance
BangladeshAbout eight different types of prototypes have been developed and three of them (charge controller, solar lamp and DC to DC converter) are currently being manufactured in large scale. About 100,000 solar lamps, 30,000 charge controllers and 6,000 DC to DC converters have been developed and are being used in the field. About 50% cost reduction compared to the imported ones has been achieved through this development. More importantly, after sales service and availability of spare parts have been ensured through this endeavor.
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Charge Controller About 30,000 charge controllers were installed up to June 2005. Initially, the failure rate was ~ 5%, which occurred mainly due to the poor quality of the printed circuit board (PCB). The rate has been reduced to 2% by improving the PCB quality.
Ballast for DC fluorescent lamps About 100,000 lamps were installed up to June 2005, operating for 4 hours each day. Initially, the failure rate was ~15%, which occurred mainly due to the poor quality fluorescent tubes. The rate has been reduced significantly by selecting right quality of tubes and electronic components.
DC-DC Converter About 6,000 DC to Dc converters were installed up to June 2005, operating for 2 hours/day. Initially, the failure rate was ~10%, which occurred mainly due to the low current rating of the transistor. This failure rate now is ~3%, which has been achieved by sourcing improved quality transistor. Figure 2 shows a sample DC-DC converter developed in Bangladesh.
Figure 2: DC to DC Converter developed by Grameen Shakti
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Vietnam Four different types of prototypes have been developed in Vietnam, and three of them (charge controller, ballast for fluorescent lamp and inverter) have been commercialized. The programme also developed DC energy saving lamp, which was the first such development in Vietnam. Local experts have been benefited with the research facilities established under RETs in Asia programme. In addition, products for PV systems are now being manufactured locally.
Charge Controller About 50 charge controllers are being used by the users of battery charging station. The overall failure rate up to June 2005 is 2%, which has mainly caused by low quality components.
InvertersTen units were made. They are being used for various purposes, e.g. cultural boat, cultural house, computer system, and solar ambulance. No major problem has been found so far.
Ballast for DC fluorescent lamps More than 700 units have been made and many of these have been installed in Ding Dong solar village and in other places of Vietnam. No major problem has been found so far.
Adaptor for color TV About 20 units have been made and are being used in the rural cultural facilities as well as in households of Vietnam. No units failed so far since the first installation in June 2000.
CambodiaTwo different types of charge controllers were developed in Cambodia, and one of them (presented in Box 1) has been commercialized. About 40 of this device have been installed with street lights at Prek Takouch bridge. The street light project was funded by the government of Cambodia.
About 40 charge controllers are being used with the street lights since December 2003. So far, no major problems have been
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reported. Figure 3 shows a sample charge controller developed in Cambodia.
Figure 3: Charge controller developed in Cambodia
The adaptive research on PV accessories development thus has helped in various ways, such as:
Price reduction of SHS in Bangladesh due to locally developed accessories was approximately 10%. The reduction obtained compared to the imported items were as follows7:
Charge controller : Imported : ~US$ 25 Present : ~US$ 10
Lamp : Imported : ~US$ 15 Present : ~US$ 7
Local capacity has been enhanced so that the accessories can be designed to any capacity required. Laboratory facilities also have been developed (Figure 3) Display options (in charge controller) can be made according to the users demand to help them understand the system status easily.
7 One 50Wp system (~US$ 500) uses 1 charge controller and 4 lights. So, cost reduction is ~US$ 50.
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After-sales service and a reliable source of accessories were established. These enhanced users’ confidence on the PV technology. Creation of employment opportunities for design, fabrication, raw material and component delivery, transportation, repair and maintenance work.
Figure 3: Laboratory facility of Grameen Shakti
Concluding Remarks The following factors were vital in the successful development and commercialization of PV accessories:
Robust designs that were based on locally available components andDevelopment of designs based on the field performance and users’ feedback.
For further details, please contact Mr. Dipal C. Barua Managing Director, Grameen Shakti, Grameen Bank Bhaban, Mirpur, Dhaka 1216, Bangladesh. Email: [email protected]
Dr. Sat Samy Under Secretary of State, Ministry of Industry Mines and Energy (MIME), No. 47, Preah Norodom Blvd. Phnom Penh, Cambodia. E-mail: [email protected]
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Mr. Trinh Quang Dung Director, Solar Laboratory, 01 Mac Dinh Chi St, 01 District, Ho Chi Minh City, S. R. Vietnam, Email: [email protected]
Related Publication Alamgir, D. Adaptive research and dissemination for development of PV technology in Bangladesh. World Renewable Energy Congress.Brighton, UK. 2000. pp-840-843.
Dung, T.Q. Energy saving technology application in solar electricity for socio-economic development. Conference of Applied Physics Serving for Socio-Economic Development, 10-11 December 2004.
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Biomass Briquetting Technology: Domestic and Small Industrial Applications Rice husk briquette has emerged as a viable and important substitute for fuel wood in Bangladesh and Vietnam. With improvements achieved in the briquetting technology, briquettes have become more cost effective than fuel wood, leading to the establishment of a briquetting industry in these countries.
IntroductionUtilization of agricultural residues is often difficult due to their uneven and troublesome characteristics. The process of compaction of residues into a product of higher density than the original raw materials is known as densification or briquetting. Densification has aroused a great deal of interest in developing countries all over the world lately as a technique for upgrading of residues as energy resources. Converting residues into a densified form has the following advantages:
The process increases the net calorific value per unit volume Densified product is easy to transport and store The process helps to solve the problem of residual disposal The fuel produced is uniform in size and quality
The process also helps to reduce deforestation by providing a substitute for fuel wood.
There are several methods available for densifying biomass. Heated-die screw press briquetting is a popular densification method suitable for small-scale applications in developing countries. In this method, the raw material (loose biomass) from the hopper is conveyed and compressed by a screw through a cylindrical die, heated by electric coil heaters. This process can produce denser and stronger briquettes compared with piston presses.
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In heated-die screw-press briquetting machine, the screw is prone to wear caused by the abrasive behavior of biomass. The wear of screw results in significant operating costs, and calls for a rather regular attention of the plant owner. The high electrical energy consumption by the briquetting process was another area of concern, which limits the widespread use of the technology.
Heated-die screw-press briquetting technology has been in use to produce rice husk briquettes in Bangladesh for several years. During a nationwide survey, it was found that there were about 900 briquetting machines used in 1997, of which 880 machines were fabricated in Bangladesh. Most of these can densify 75-120 kg of biomass per hour. They were operated with 15, 20 or 25 horsepower electric motors. The only raw material used was rice husk. A significant potential for energy and cost savings existed, while there was further scope for enhancing the operating convenience.
Heated-die screw-press briquetting technology was introduced in Vietnam in the eighties, but the interest was quickly lost due to many technical and economic issues. It was introduced again through the RETs in Asia programme in 1997. Efforts were made to ensure that the key issues that prevented the technology from taking off earlier were addressed. Currently, there are about 500 households using rice husk briquettes for daily cooking in Vietnam. About 800 - 1000 tons of briquettes are produced every year. Briquettes are used as single fuel, or mixed with fuel wood and other biomass fuels.
Rice husk briquettes have also been used in brick kilns in an enterprise located in Binh Duong province (South of Vietnam). Trial production using 20 tones of rice husk briquettes showed good results. In the same province, five briquetting machines have been installed in a rice mill to produce briquettes from rice husk produced at the plant.
Briquetting Technology
BangladeshUnder the RETs in Asia programme, Khulna University of Engineering and Technology (KUET) worked to reduce the technical and
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operational problems, and to adapt the technology to conditions in Bangladesh, for the type and quality of raw materials available locally. Adaptive research activities carried out at KUET resulted in the development of improved and cost-effective briquetting packages.
The major achievements of the research were the enhancement of screw life and reduction in briquetting energy consumption, leading to reduction in the production cost of briquettes. Two technology packages were developed by KUET on improved heated-die screw-press briquetting system, each consisting of a machine to produce briquette, selected accessories, and a stove to burn briquettes efficiently. Accessories developed included a biomass pre-heater, die-heating stove and a smoke removal system. With the packages developed, it is possible to produce rice husk briquettes at a cost of about Tk 1.72 per kilogram8, which was very competitive with the cost of fuel wood in the local market (Tk 3.75/kg).
Technical Improvements The briquetting machines already used commercially in Bangladesh are of heated-die screw-press type and rice husk is mainly used as the raw material. Wear of the screw is the main problem of existing briquetting machines. During briquetting, the biomass raw material slides on the screw surfaces. This sliding action cause wear as the biomass rubs against the surface of the screw continuously. As a result, the root of the screw and also the flight surface get damaged. The wear is more pronounced with more abrasive raw materials such as rice husk. Research was undertaken with the aim of protecting the screw surface from wear so that the screw could be used for a longer duration. Mild steel is recommended as the base metal for screw because of its availability and low cost. To improve the hardness and wear resistance of the screw surface, the portion of the screw which experiences most wear (about 15 cm from the front end) was resurface with hard-facing electrode XHDN 6715. The technique increased the screw life from 3 hours (without hard facing) or 6 hours (with conventional hard-facing electrodes) to 22 hours per run,
8 1 US$ 64 Taka (Tk), July 2005
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resulting in improved economy. The briquetting machine can now be operated continuously for three shifts before it requires a screw replacement. The worn out screw can be repaired by welding and resurfacing the damaged flights for a nominal cost, and re-used, typically up to ten times.
Adaptive research at KUET also focused on the screw profile and die design of the briquetting machine. An optimum design of screw and die which consumes the least energy for briquetting rice husk was developed. A screw pitch of 38.1 mm and a die taper angle of 2.32showed the best results for rice husk.
Electricity consumption for die-heating plays a major part in the total briquetting production cost. A briquette-fuelled stove was therefore developed, to replace the electrical coil heaters used for die heating, resulting in a reduction of about 25% in the total electricity consumption.
Heating loose biomass before feeding into the briquetting machine reduces the power required for the motor, and gives an added benefit of longer screw life. Research has shown that preheating can save up to 10% of the total electrical energy required for briquetting rice husk in electric motor-driven briquetting machines. KUET developed a raw material pre-heater which uses hot exhaust gases from the die-heating stove, fuelled by biomass briquettes. The pre-heater further reduced the briquetting energy consumption.
Another development was a briquetting machine that can be run without electricity as shown in Figure 1. The electrical motor was replaced with a diesel engine and the electrical coil heaters by a kerosene stove. The machine is attractive even at locations where electricity is available: the cost of fuel for running the engine (diesel) is only 50% of the cost of electricity required for the motor.
By incorporating these improvements in a prototype briquetting system, briquettes could be sold for Tk 2.50/kg. This competes with fuel wood sold in the local fuel wood shops, which typically costs Tk 3.75/kg. The production cost reduced from Taka 2.03 (US$ 0.04) to Taka 1.78 (US$ 0.03) per kg of briquette, while the cost of electrical
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energy consumption to run the briquetting system decreased from Taka 68.80 (US$ 1.18) to Taka 48.80 (US$ 0.81) per hour. Local availability of materials (base metal and welding electrode) in fabricating and repairing the screws contributed to a further reduction in costs.
In addition to cost reductions, KUET also developed a new mechanism for changing the worn out screws in a shorter time, thus reducing the machine downtime during screw replacement significantly.
Fabrication of briquetting machines and production and selling of briquettes (Figures 2 and 3) are already established in the Khulna region of Bangladesh. With the briquetting technology reaching maturity and the growing acceptance of briquettes as a replacement for fuel wood in the residential and cottage industry sectors, the briquetting industry is poised for more growth in the near future.
Financial Analysis Financial analysis of the improved briquetting system, both for electric motor and diesel engine, indicate a payback period of less than one year. Table 1 shows the results of the analysis. The analysis is based on the following assumptions:
Figure 1: Off-grid briquetting machine (screw run by diesel engine,and die heated by kerosene stove)
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10 hours of operation per day 25 days per month of operation Machine life: 10 years Screw life: 77 hours (total lifetime after repairing and reuse) Briquette production rate: 90 kg/hr Rice husk price: Tk 0.90/kg Briquettes selling price: Tk 2.50/kg Operator charges: Tk 10/hr Interest rate: 10%
Figure 2: Rice husk briquettes in a fuel wood shop
Figure 3: Selling briquettes in a ‘mobile shop’
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Table 1: Financial analysis of the briquetting systems
Description Electric system Diesel system Production cost, Tk 1.72/kg 2.06/kg Net profit per day, Tk 387 702 Net profit per year, Tk 116,070 210,720 Payback period, year 0.63 0.33 Benefit cost ratio 1.21 1.45
With such a short payback period, the briquetting systems make good economic sense, and demonstrate a viable business model.
Vietnam A commercially operating briquetting machine was imported from Bangladesh, and was modified through adaptive research to suit the local conditions and requirements. Training was provided to the technicians involved (in Bangladesh) on the design, assembly, operation and maintenance of the machines. Studies were conducted locally in Vietnam, and several biomass stoves that can effectively burn rice husk briquettes were developed.
Technical Improvements Institute of Energy carried out adaptive research on the imported machine, and introduced key improvements. Figure 4 shows a briquetting machine in commercial operation. The briquetting screw and die were redesigned to reduce briquetting energy consumption (Figure 5). The screw profile was modified, and diameter increased, to produce 71 mm diameter briquettes instead of 55 mm produced in the original machine (Figure 6). The briquette production rate was increased from 70 kg/hour to 90 kg/hour. The new design of screw and die also allowed a reduction in the size of motor from 20 to 15 horse power.
The improvements resulted in an overall reduction of 25% electricity consumption. The cost of briquette reduced from 1.1 to 0.9 times the cost of fuel wood, thus effectively competing with fuel wood in the local market.
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Figure 4: Improved briquetting system in commercial operation
Figure 5: The redesigned briquetting screw and die
Figure 6: 71 mm and 55 mm diameter briquettes
Briquette stoves
BangladeshBiomass briquettes have different density and combustion characteristics compared to other biomass fuels such as wood. Therefore, it is essential to develop suitable low-cost briquette stoves to popularize biomass briquettes as a domestic fuel in Bangladesh. KUET developed briquette-fuelled stoves for domestic
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and small business use (Figures 7 and 8). Over 400 of these stoves were distributed to a local village community with whom the stoves became very popular.
Vietnam
With the introduction of rice husk briquettes in Vietnam through the RETs in Asia Programme, several households have chosen briquettes as fuel for cooking. Briquettes are attractive as they are cheaper to fuel wood. Stoves designed to use briquettes as fuel stoves are now available in the country. These stoves can burn rice husk briquettes efficiently, with less or almost no smoke. Advantages of the rice husk briquette fuel include sustainable supply from the local rice milling
Figure 7: Improved briquette stove developed at KUET
Figure 8: Briquette stoves dissemination
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industries, non-exposure to price fluctuations as experienced with fossil fuels and fuel security.
Under RETs in Asia Programme, the requirements and design features of briquette stoves were first identified by studying many existing wood and coal stoves used in Vietnam. These stoves were tested and evaluated by considering the relevant design and operational aspects such as efficiency, emission of pollutants and convenience of use. Altogether, four types of briquettes stoves were developed at the Institute of Energy. Figures 9 and 10 illustrate three of the stoves thus developed. The stoves offered high efficiency while emitting fewer pollutants.
Figure 9: Two types of single pot briquette stoves
Figure 10: Top burning stove for briquettes
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More than 300 briquette stoves have so far been disseminated within the programme. Several others have been sold commercially through stove manufacturers. Table 2 presents the cost details and payback period for a briquette stove in comparison to a traditional stove and an improved stove that uses fuel wood in Vietnam.
Table 2: Selected indications of the biomass briquette stoves Description Unit Traditional
stoveImproved
wood stoveBriquette
stove
Type of fuel used Fuelwood Fuelwood Briquettes
Heating value kcal/kg 3,500 3,500 3,300
Stove efficiency % 15 20 33
Annual household fuel consumption
kg/household/ year
1,738 1,304 838
Stove price VND/unit 0 – 5,000 30,000 30,000
Fuel price VND/kg 500 500 500
Annual fuel cost VND/household/year
869,048 651,786 418,962
Cost saving VND/household/year
- 217,262 232,823
Simple pay back period
Months - 2 2
Success features and concluding remarks With sufficient know how, experiences and capacities for local fabrication of low-cost and much more efficient briquetting systems, biomass briquetting technology is much more attractive than before for interested entrepreneurs. Presence of trained engineers and technicians for maintenance and repairing is an added incentive. With briquettes being sold at a cheaper price than fuel wood, the technology seems to offer an ideal business opportunity for small entrepreneurs in rural Bangladesh.
An initial countrywide survey in 1997 showed that the average cost of a briquetting machine was about US$ 2500, which is quite high for small investors in Bangladesh. KUET’s efforts in improving design and fabrication methods have brought down the cost of briquetting
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machine of similar production capacity to about US$ 800 (2002). It was also observed that the number of briquetting machines in operation in Bangladesh was about 900. This increased to more than 2000 in the year 2002, with the introduction of improved technology and better profitability.
The impact of the briquetting programme in Bangladesh is multi-faceted: generation of rural employment and income, solution to the disposal problems of large quantities of unutilized rice husk, efficient utilization of an indigenous energy resource and associated enhancement of energy security; and a reduction in the use of wood and consequent conservation of forests. The activities related to briquette-production such as briquetting machine and components fabrication, screw repairing, transportation, and marketing of rice husk and briquettes, have contributed in instituting a small industrial and service sector in Bangladesh.
In Vietnam, although currently briquette stoves are used mainly for household cooking, there is a large potential for their use in the small and cottage industries sector, especially in the food processing business. Some stoves of bigger size have already been demonstrated for food processing.
For further details, please contact Prof. Nawsher Ali Moral Professor, Khulna University of Engineering and Technology Khulna, Bangladesh. Email: [email protected]
Dr. Pham Khanh Toan Director, Institute of Energy, Khuong Thuong - Dong Da, Hanoi, SR Vietnam. E-mail: [email protected]; [email protected]
Related Publication Choudhuri, A.R., Moral, M.N.A. and Kazim, K.A. 1998. ‘Techno-economic Feasibility of Biomass Briquetting in Bangladesh’. Proceedings of the National Seminar on Utilization of Renewable and Alternative Energy Sources for Sustainable Development (NSURAESD ’98). BIT Khulna, Bangladesh, pp 66-71.
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Islam, M.M., Khan, K., Moral, M.N.A. and Islam, M.S. 2003. ‘An Investigation on the Raw Materials and Products of the Briquetting Machine’. Proceedings of the National Seminar on the role of Renewable and Alternative Energy Sources for National Development (SRRAESND-2003), Khulna, Bangladesh, pp 35-42.
Moral, M.N.A., Islam, M.M., Rahman, A.N.M.M. and Gani, M.A. 1998. ‘Scope of Biomass Briquetting in Bangladesh’. Proceedings of the National Seminar on Utilization of Renewable and Alternative Energy Sources for Sustainable Development (NSURAESD ’98), BIT Khulna, Bangladesh, pp 51-65.
Moral, M.N.A. 2003. ‘Biomass Briquetting: Bangladesh Perspective’. Proceedings of the National Seminar on the Role of Renewable and Alternative Energy Sources for National Development (SRRAESND-2003), Khulna, Bangladesh, pp 17-23.
Rahman, M.M., Khan, K., Moral, M.N.A., and Mizanur Rahman, A.N.M. 2003. ‘Biomass Briquetting Technology and Environmental Pollution’. Proceedings of the National Seminar on the role of Renewable and Alternative Energy Sources for National Development (SRRAESND-2003), Khulna, Bangladesh, pp 24-30.
Toan, P.K., Nguyen, D.C., Nguyen, T.Q. and Phi, K. S. 2000. ‘Application of Briquetting Technology to Produce Briquettes from Agricultural Residues and By-products’. Proceeding of the World Renewable Energy Congress, Brighton, UK, 2000, pp 1416-1419.
Toan, P.K., Nguyen, D. C. and Leon, M. A. 2005. ‘Activities and Achievements of a Biomass Briquetting Project in Vietnam’. World Renewable Energy Regional Congress & Exhibition 2005, 17-21 April 2005. Jakarta, Indonesia.
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White LED Lamps: Replacing the Kerosene Lamps for Rural Home Lighting
Inadequate supply of good quality fluorescent lamps in the rural market poses difficulties for Solar Home Systems (SHSs) use. In addition, only high-income group of the rural areas could afford SHSs powered by PV at the current price level. To make the best use of PV system, an innovative approach is necessary to reduce the system’s price and also eliminate the problems associated with the low quality fluorescent lamps. In this context, white light emitting diode (LED) lamp has become a promising option.
BackgroundThe major drawback of a traditional solar home system is the high cost of photovoltaic module, which is not affordable to the mass rural poor people. Secondly, the durability of the solar lamp is also very low and is prone to damage and require frequent replacement of the bulbs, increasing repair/maintenance cost. To address these issues, an initiative was undertaken by the Center for Renewable Energy (CRE), Nepal to develop lamps using white light emitting diodes (WLEDs). The attractiveness of WLEDs is due to its extremely low power consumption (0.324 W per LED with light intensity of 5 Candela (Cd), longer lifetime extending over 10,000 hours, and the ability to be powered by smaller size PV modules. This has reduced the cost of solar home system and made it affordable to the poor villagers. In addition, these lamps provide a cleaner environment in the households. Each system, consisting of 3 WLED lamps, would lead to saving of 2 liters of kerosene and 2 pairs of dry cell per month for each household.
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Development of WLED Lamps The lamps have been developed by incorporating three WLEDs in a single case with a concave lens on the top to deflect light outward. Each of the lamps consumes about 100 mA at 3.6 VDC.
A 1.8 Wp module at 12 V will generate about 150 mA. For the average solar radiation available in Nepal, the daily available energy from the module would be around 750 mAh. Therefore, one lamp could be used for 7.5 hours/day. Thus, in rural households using two lamps daily for 3 hours, a small radio could additionally be operated.
Box 1 presents the technical features of two different portable lamps for use of rural households.
Box 1: Technical Features
Type A: Portable lamp
Three 6 Cd. WLEDs, Three 400 mAh NiMH AA size rechargeable batteries, Socket for charging, and Socket for powering a small radio with 3 VDC input.
Type B: Portable lamp
Two ceiling mounted WLED lamps with six WLEDS each, One maintenance free, lead-acid battery (6Ah, 12 V), Charging socket, Two outlets for lamps and one outlet for 3 V radio
A WLED with luminous flux of 5 Cd consumes 20 mA of current at 3.6 V. In other words, the power consumed by one WLED is 72 mW. Field studies indicated that a lamp with 3 WLEDs is sufficient for use as a table lamp for reading, whereas 8 WLEDs are required for use as a ceiling lamp for general lighting. Power consumption by these LEDs is far less than the power consumed by typical 7 or 9 W compact fluorescent lamps used in solar home systems.
WLED lamps require very little or no maintenance. The average life of the lamps is about 10,000 hours. When the LEDs become non-
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operational, they can be replaced. Figure 1 shows a lamp with six WLEDs.
User’s Feedback Feedbacks from the users indicate that the intensity of the light is sufficient for domestic purposes and good for reading and the lamps make the solar home system affordable by reducing the size of the PV modules.
Figure 1: Ceiling mounted WLED lamp
Concluding Remarks The WLED lamp is mainly targeted to those using kerosene lamp for lighting, who cannot afford (the high cost of) solar home systems. In addition, the frequent replacement of fluorescent lamps is also a major expense for them. About one hundred and fifty units of WLED lamps are now operating in the rural areas of Nepal. The performances of these units are satisfactory. The successful demonstration of the WLED lamp shows the advantages of these lamps over kerosene lamp and fluorescent lamps as follows:
Kerosene lamp is hazardous for health due to its smoke, The illumination intensity of kerosene lamp at a distance of 20 cm is about 35 Lux whereas it is 537 Lux for a WLED lamp, Power consumption of WLED lamps is much lower compared with fluorescent lamps used in solar home systems. This gives room
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for using several lamps with the same module, or reducing the module size for the same number of lamps.
For further details, please contact Prof. Dinesh Sharma Executive Director, Center for Renewable Energy, P.O. Box 589, Ga-2/717 Bag Bazar, Kathmandu, Nepal. [email protected]
Related Publication Sharma, D.K, Shrestha J.N. and Shrestha B.R. 2005. Low cost lighting system to replace kerosene lamps, World Renewable Energy Regional Congress, Jakarta, Indonesia, 18-21 April 2005.
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Solar Dryers Offer Income Generation OpportunitiesSolar drying is an economically attractive option for producing dried products in commercial scale in Nepal. Drying vegetables in solar tunnel dryers prove to be an effective income generating activity for small entrepreneurs. A solar tunnel dryer modified by Nepal’s Research Centre for Applied Science and Technology (RECAST) to improve performance and to enhance the operating convenience, can dry about 70 kg of fresh vegetables in a single loading. It has been tested with several vegetables, including radish, onion, carrot, ginger and mushroom. Fruits are also dried in the tunnel dryer. Most of the dried fruits are made into candies and sold in the local market while the dried vegetables are exported.
BackgroundDried food products are used in Nepal in the form of snacks, soups and vegetables. Some fermented and dried vegetables, dried spices and medicinal herbs are also used for preparing traditional meals and medicines. Most traditional dehydrated food products were prepared by open sun drying and very small quantities of these products entered into the market. With the introduction of solar drying technology and the availability of good quality dried products in sufficient quantities, the solar drying systems are gaining popularity.
Recently, mountaineers, trekkers and tourists have become one of the main consumer groups of dried fruits. Solar dried fruits, e.g. apple, apricot, mango etc. are sold in Kathmandu and other cities of the country. In response to rise in consumers’ demand for dried products in the recent years, some entrepreneurs have started solar drying of various fruits, vegetables and herbal products using solar tunnel dryers. Apart from promoting environmentally friendly solar drying technology, the business is also economically rewarding for the entrepreneurs. Additional benefits include fresh job opportunities
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for local women employed in pre-processing activities such as peeling, cutting, slicing, pitting, etc. and also in transporting and marketing of the dried products.
Project details An entrepreneur involved in drying of different fruits, vegetables and related products is a former School Headmaster and now a farmer-cum-businessman. He is also a wholesaler of fresh fruits and vegetables in Kathmandu. He has been producing jams, juices and candies from the strawberries grown in his own land and supplying them to department stores, hotels, restaurants and foreign institutions. He has also been running a candy business with lapsi (Choerospondias axillaris) and strawberry as raw materials.
Candies are made mainly from fruits, such as mango, strawberry, lapsi etc. The process consists of mixing fruit pulp with salt and/or sugar and drying the mixture to a safe level of moisture content for storage. A problem encountered in candy making is during the process of drying. Initially, the entrepreneur used electrical oven and ordinary solar cabinet dryer for this purpose. But this was not satisfactory in terms of quality of the dried products and was not very profitable. The entrepreneur therefore looked for alternatives, and selected the solar tunnel dryer developed in RECAST under RETs in Asia programme. RECAST installed a solar tunnel dryer (Figure 1) in his premises, and provided him training on its operation and maintenance. The installation proved successful with the production of better quality candies in the solar tunnel dryer and a higher profit margin.
With the successful production of lapsi and strawberry candies, the entrepreneur extended the range of his products to include other fruits and vegetables such as, banana, tomato, mushroom, cauliflower, radish etc. Besides three of his family members, he has employed twelve people for production of solar dried products.
Being a wholesaler of fresh fruits and vegetables, the entrepreneur dries his highly perishable raw materials that would otherwise go wasted.
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Figure 1: Tomato slices being dried in the solar tunnel dryer
Design of the dryer The solar tunnel dryer consists of six flat plate air-heating solar collector modules and eight drying chambers connected in series in a particular layout, thus forming a 17m long tunnel. Four of the six collector modules are fixed at one end, next to the air inlet opening, while two collectors are located in the middle. The two solar collector modules at the middle help prevent condensation of moisture on the inner surface of the glasses, by maintaining the temperature of air inside the tunnel at reasonably high levels.
Each module has an outer box and an inner box, with glass wool insulation between them. The solar collector and drying chamber frames of the dryer are made of wood and GI sheets, insulated with glass wool, and glazed at the top with ordinary window glass, available in the local market. A corrugated sheet GI absorber, coated with flat black paint, is fixed inside the inner box. Four millimeter thick window glasses are used for glazing the collector.
The eight dryer modules are fixed between the collector modules. Each module has two partitions, and each partition has two trays and a glass door hinged at one side of the door frame. The glass doors can be opened at the top, for loading and unloading of the product. The trays are made of aluminum frames and stainless steel wire mesh, on which the products to be dried are loaded in thin layer.
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A 370W AC exhaust fan connected at the rear end of the tunnel sucks ambient air into the tunnel. Warm, moist air leaves the tunnel through the exhaust fan. The integrated collector-dryer unit is supported at the bottom by a steel frame, which rests on footings made of MS pipes. The footings are firmly fixed to the ground using cement concrete.
Cost details A simple cost analysis of the dryer is presented below. The calculations show cost details for drying two products, tomato and lapsi-strawberry fruit pulp.
A. Initial investment
The solar tunnel drying system costs NRs 200,000 (US$ 2703)9.
B. Technical assumptions
Only 130 days of drying was considered. Operation during the other days of the year depends on the availability of fruits and vegetables for drying.
Tomato Drying time: 1 day/batch. Tomato is 150 kg per batch. The dryer approximately produces 90 batches (90 days of dryer operation).
Lapsi-strawberry Drying time for lapsi-strawberry is four days per batch. Lapsi weighs 135 kg and strawberry weighs 90 kg, per batch, respectively. The dryer approximately produces 10 batches (40 days of dryer operation). Sugar used for candy sweetening is 150 kg per batch. Powdered milk used in candy making is 15 kg per batch.
9 1 US$ 74 NRs (Nepalese Rupees), March 2004
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C. Operating expenses
Market price: o Tomato: NRs 15 per kg o Lapsi: NRs 135 per kg o Strawberry: NRs 90 per kg
Preservatives: a. Sugar for lapsi-strawberry candies costs about NRs
40 per kg b. Powdered milk costs about NRs 250 per kg c. Spices costs around NRs 4000 per batch
Packaging material cost: NRs 1 per pack (50 grams per pack).Labor cost for the workers (12 laborers per day): NRs 83 each per day. Electricity tariff: NRs 9 per kWh. Electricity is used 4 hours per day.Delivery cost: 3% of the sales revenue. Repair and maintenance: 5% of the total investment cost. Depreciation is by straight-line method with a salvage value of 5% of the investment cost.
D. Revenue
Recovery rate is around 8% by weight of tomato. Thus, the dryer produces a total of 1,080 kg of dried tomato from the 90 batches (13,500 kg) of fresh tomato. For candy, recovery rate is around 60%. Thus, approximately 2,340 kg of lapsi-strawberry fruit candies are produced from the 10 batches of fresh lapsi-strawberry. The selling price of dried tomato is NRs 400 per 50-g pack. The selling price of lapsi-strawberry candies is NRs 250 per 50-g pack.
Details of the expenses for the 130 days of drying operation of 13,500 kg of tomatoes and 2,340 kg of lapsi-strawberry to produce dried tomatoes and lapsi-strawberry candies are given below. The
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total expenses for the drying activities amount to a total of US$11,258. The itemized expenses are:
Tomato : NRs 202,500 Lapsi : NRs 135,000 Strawberry : NRs 108,000 Sugar : NRs 60,000 Powdered milk : NRs 37,500 Spices : NRs 40,000 Labor : NRs 130,000 Electricity : NRs 1,170 Packaging : NRs 68,400 Delivery Cost : NRs 30,510 Depreciation : NRs 10,000 Repairs and Maintenance: NRs 10,000 Total Expenses : NRs 833,080 (US$ 11,258)
The total income is estimated based on the sale of dried tomatoes and lapsi-strawberry candies. The projected total revenue from selling 50-gram packs of the dried products reaches up to US$13,743 while the net profit amounts to US$2,485 after deduction of the operational expenses. The total income and net profit are itemized as follows:
Total income from the sale of dried tomatoes : NRs 432,000 Total income from the sale of candies : NRs 582,000 Total revenue from sales : NRs 1,017,000 (US$ 13743) Total net profit : NRs 183,920
(US$ 2,485)
Monitoring and evaluation The solar tunnel dryer was monitored by RECAST. The dryer generally performed well, and no significant maintenance was required during the initial one-year period.
The dried products were found to be of good quality. Drying was faster in the solar tunnel dryer compared to open sun drying. The
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dryer also saved labor costs during cloudy and rainy weather conditions as the products do not require covering up or removal from the drying field during such unfavorable weather conditions.
Concluding Remarks Use of the solar tunnel dryer presents a viable option for drying highly perishable fruits and vegetables to produce dried fruit candy products.
Experience in Nepal clearly indicates that tunnel type solar dryers are financially viable and can be used to dry fruits and vegetables, and thus reduce wastage of these highly perishable commodities.
For further details, please contact Prof. Mohan Bikram Gewali Executive Director, Research Centre for Applied Science & Technology (RECAST), Tribhuvan University, P. O. Box 1030, Kirtipur, Kathmandu, Nepal. E-mail: [email protected]
Related Publication Joshi, C.B. Performance Evaluation of a Modified Solar Tunnel Dryer, Proceedings of the 3rd National Conference on Science and Technology, Royal Nepal Academy of Science and Technology (RONAST), Kathmandu, Nepal, 1999.
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Conclusion The institutions participating in the RETs in Asia programme initiated and implemented different technologies, applications and techniques for promoting selected renewable energy technologies in their countries.
Although it is recognized that PV systems are vital in meeting basic electricity requirements of rural and remote areas, the technology has remained out of reach to many people due to a variety of reasons such as high system cost, lack of reliable after-sale service, lack of overall user confidence regarding the technology etc. The experience of RETs in Asia suggests that these barriers can be overcome through demonstration, reduction in the system’s cost, and improving its reliability through producing accessories locally. Experience in Bangladesh suggests that PV systems can be promoted commercially by offering a package of appropriate financing mechanisms, enhancing users’ knowledge about the system and assurance of after-sale service.
Commercial drying of fruits and agricultural products is new in most developing countries. However, the introduction of renewable energy based drying technologies shows that dried products are accepted by local users as well as the export market. These systems provided income generating opportunities for individuals, private companies and cooperatives. In addition, biomass (i.e. rice hull) which was previously considered as a waste that is very difficult to dispose proved very useful for generating heated air for small and medium scale drying purposes.
In most developing countries there is increasing shortage of fuel wood, while large quantities of agricultural residues remain unutilized due to their uneven and troublesome characteristics. RETs in Asia experience in the participating countries shows that briquetted residues can be an important substitute of fuel wood if reliable locally made/low cost briquetting machines are available and private entrepreneurs are involved in producing and marketing briquettes.
