Preference and consumption pattern of biomass fuel in some disregarded villages of Bangladesh

Consumer's preference and consumption pattern of biomass fuel, fuel types and energy use category has been studied in the disregarded villages of Bangladesh. The study was conducted both in the inland and island areas. Biomass energy in the study area was used in domestic cooking, tea stalls, brickfields, bakeries, paddy parboiling and pottery. Assessment of consumption in domestic cooking was done by means of multistage random sampling and that in the tea stalls, brickfields, bakeries, paddy parboiling and pottery by means of complete enumeration of the sampling unit. Based on the homestead size respondents were categorized into small, medium and large and a total of 60 homesteads (30 from inland and another 30 from island areas), 20 from each category were selected randomly for the study. The study revealed that natural gas was quite absent and stems, branches and twigs, leaves of trees, agricultural residues, shell and coir of coconut, saw dust, brush wood, rhizomes of bamboo, and cowdung were the biomass fuel used by the respondent. Nine fuelwood species were identified as the most preferred in the study area. Consumption pattern was mostly traditional. Each year preceding the rainy season cyclonic action damages a large quantity of biomass energy sources. Though at the initial stage of rainy season (April–May) there remain a more or less good collection of fuelwood to the user as the byproduct of cyclones and storms, the last part of the rainy season (July–August) was identified as the fuel shortage period.     

SOLAR COOKER ACCEPTANCE IN SOUTH AFRICA: RESULTS OF A COMPARATIVE FIELD-TEST

A one-year comparative field-test of 7 different types of solar cookers, involving 66 families in 3 study areas in South Africa, has been conducted by the South African Department of Minerals and Energy (DME) and the Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ). Overall, families use solar cookers on 38% of all days and for 35% of all cooked meals; they express clear preferences for certain cooker types. Solar cookers, together with wood (stoves and open fires, used on 42% of all days), are the cooking appliances most used. Fuel consumption measurements show overall fuel savings of 38%, resulting in estimated pay-back periods (through monetary fuel savings) from 8 month onwards, depending on the type and region. Economic analysis, acquisition of test cookers by users after the placement period as well as an independent market study, have led to a second programme phase of commercial pilot dissemination of locally produced cookers, adapted according to field-test experiences.     

Wood fuel use in the traditional cooking stoves in the rural floodplain areas of Bangladesh: A socio-environmental perspective

A study was conducted, using a multistage simple random sampling design, to determine the structural characteristics of the traditional cooking stoves, amount of wood fuel consumed in the rural floodplain areas in Bangladesh, and also to figure out the socio-economic and environmental consequences of wood fuel usage in the traditional cooking stove. The study showed that family size, income, amount cooked and burning hours significantly affected the amount of wood fuel used per family per year. Taking into account different family sizes, the study observed that 4.24 tonne fuelwood were consumed per family per year. The study showed that 42% of families used only biomass fuel, 5% used liquefied petroleum gas (LPG) and 53% used kerosene along with biomass fuels. The main source of biomass fuel was homestead forests (40%). It has been figured out that the incomplete combustion of biomass in the traditional cooking stove poses severe epidemiological consequences to human health and contributes to global warming. The study also showed that 83% of the respondents would prefer improved cooking stoves over traditional cooking stoves.     

The development impact of solar cookers: A review of solar cooking impact research in South Africa

Solar cooking is often considered “a solution looking for a problem”. Solar cookers have long been presented as an interesting solution to the world's problem of dwindling fuel wood sources and other environmental problems associated with wood fuel demand for cooking. However, recent GTZ field work in South Africa showed different benefits instead: the use of solar cookers resulted in appreciable fuel and time savings as well as increased energy security for households using commercial fuels. These observations are based on field tests in South Africa that started in 1996 to investigate the social acceptability of solar cookers and to facilitate local production and commercialisation of the technology. Impact studies and use rate studies have been carried out by a number of different organisations since the inception of the project and although commercialisation of the technology has not been achieved to its fullest potential, impact studies indicate that solar cookers have a positive development impact on households through fuel-, energy- and time savings. The article aims to summarise the findings of the various studies and present an overview of use rates and impact data. A variety of factors influence solar cooker use rates, which in turn determine impacts. Some factors are related to the user, some to the environment in which the cooker is used and some to the cooker itself. Ultimately, the data shows that on average, only 17% of solar cooker owners do not use their stoves after purchase and that active solar cooker users utilise their stoves on average for 31% of their cooking incidences. Since the majority of solar stove buyers actually use their stoves and obtain real benefits, this suggests that that solar cookers are indeed not a solution looking for a problem but a solution worth promoting.     

Development of a multi-purpose solar tunnel dryer for use in humid tropics

Particularly in tropical countries, a high percentage of crops are spoiled during the drying period due to permanently high relative humidity and sudden rainfalls. Open air sun drying and smoke drying, which are traditional drying methods in these regions, lead to insufficient product quality. In order to be marketable, the produce meant for sale on the world market has to meet high quality standards. Otherwise the price will decline resulting in low profits for the exporting country and the producing farmer. To produce high quality products for the world market as well as to reduce losses, the development of suitable dryers for tropical regions is urgently needed. A multi-purpose solar tunnel dryer, orginally developed for the use in arid zones, was modified to enable operation under tropical weather conditions. This type of dryer consists of a small centrifugal blower, a collector and a tunnel drying chamber. To prevent penetration of water into the construction and subsequent flooding, the solar dryer was installed on a wooden substructure. To heat the drying air during cloudy and rainy days, particularly in the rainy season, a biomass furnace with heat exchanger was integrated into the solar drying system. The construction consists exclusively of materials available in Java. Only low energy requirements are necessary to run the blower. Results showed that compared to natural sun drying, the drying time of cocoa, coffee and coconut could be reduced up to 40%. Solar drying improves the quality of the products in terms of colour, flavour and appearance, reduces the risk of microorganism growth, prevents insect infestation and contamination by foreign matters and mycotoxins. The products dried with the solar drying system meet the national and ingternational market standards. Investigations further showed that even during the rainy season it was possible to dry the products to the final moisture content which is needed for storage and marketing. The modular system allows adaptation to different farm sizes as well as cooperative use.     

Comparative study of conventional and SBCI cardboard solar ovens

Two folding and light solar ovens designed and constructed by Solar Box Cookers International (SBCI), Sacramento, U.S.A., have been studied experimentally. Furthermore, their performance is compared with standard two glass solar ovens designed by one of us (S.S.N.), in the climate of Costa Rica. According to our measurements, made with and without load, taken during 30 different days, both cardboard ovens are 15–25% less efficient than the conventional oven and, secondly, the improved SBCI oven is slightly better than the previous SBCI oven.     

Fuel wood consumption pattern of tribal communities in cold desert of the Lahaul valley, North-Western Himalaya, India

Fuel wood is the primary source of energy in rural areas of the Himalaya. Lack of resources, extremely low temperature and xeric climatic conditions of the study region (Khoksar – 3200 m, Jahlma – 3000 m, Hinsa – 2700 m and Kuthar – 2600 m) of cold desert of the Lahaul valley has led to serious deforestation due to excessive use of fuel wood in the past. On the basis of family sizes, fuel wood consumption was recorded less in large family as compared to small family. The fuel wood is used for various activities such as cooking, water heating, room heating, lighting and livestock rearing, etc. Fuel wood consumption was highest in high altitude villages as compared to low altitude villages irrespective of family size. Fuel wood consumption of 4.32 ± 0.99 kg/capita/day was highest at Khoksar for small family during winter season followed by the autumn (2.25 ± 0.15 kg/capita/day) and summer (1.38 ± 0.13 kg/capita/day). The labour energy expenditure for fuel wood collection was also highest for Khoksar (91.91 MJ/capita/year), followed by Hinsa (61.29 MJ/capita/year), Kuthar (52.01 MJ/capita/year) and Jahlma (51.89 MJ/capita/year), respectively. It was found that fuel wood consumption in the study region was influenced by the local cold climate and season of the year. The present information on fuel wood consumption pattern at different altitudes would be helpful in designing appropriate technologies to develop energy plantations in the region.     

Evaluation of the performance of improved biomass cooking stoves with different solid biomass fuel types

We have studied the performance of different types of improved solid biomass cookstoves (Two natural draft and one forced draft) in comparison to the traditional cookstove (control) while preparing a particular meal with a variety of solid biomass fuels (e.g. fuel wood, dung cake and crop residue). Five replicates of each type of cookstove and fuel were maintained. The study was conducted in an Indian rural kitchen. There was no significant difference in the indoor concentrations of PM_2.5 and CO when natural draft and traditional cookstoves were used with any type of solid fuel. However, significantly lower concentrations of PM_2.5 and CO were recorded with forced draft stoves compared to others. While cooking with different types of solid biomass fuels, the concentrations of PM_2.5 and CO in the indoor environment were decreased by 21–57% and 30–74% respectively with the forced draft cookstove in comparison to the traditional cookstove. The fuel consumption, cooking duration and thermal efficiency of a particular stove to prepare a particular amount of food also differ depending on the type of the solid fuel used for the cooking purpose. The thermal efficiency of traditional, natural draft and FD cookstoves were in the range of 15–17%, 16–27% and 30–35% respectively for different types of solid biomass fuels. However, further studies on the performance of stoves are required based on the size and type of fuel wood or crop residues.     

On-line recording of solar cooker use rate by a novel metering device: Prototype description and experimental verification of output data

A metering device for the determination of solar cooker use rate is presented. The device records food temperature, ambient temperature and irradiance. Automatic data evaluation yields the number of cooking cycles, cooking time, food “thermal mass”, as well as the impact on fuel consumption and GHG emission compared to other cooking techniques. Metering results are compared with actual conditions for box-type and concentrating solar cookers and found to be in agreement.     

Energy profiles of rural domestic sector in six un-electrified villages of Jorhat district of Assam

A comparative analysis of the household energy consumption patterns and available biomass energy in six un-electrified villages of the Jorhat district of Assam is presented. This empirical study examines how the energy consumption patterns in six villages (Gariabhonga, Khongia, 8 No. Spur, Na-Jankhona, Upper-Deorigaon and Nam-Deorigaon), each representing different categories, are influenced by the locally available biomass energy resources. The study reveals that the total energy consumed in GJ/capita/year for domestic activities ranges from 7.503 to 12.692. Major findings in the domestic sector are: (1) fuel wood is preferred for domestic energy consumption, (2) easy availability encourages excessive consumption, (3) 21.5 to 42% more energy is consumed in winter than in summer for meeting cooking, water heating and space heating needs, (4) rice residues and dung are present in abundance but go to waste owing to the easy availability of fuel wood, and (5) commercial fuel kerosene is the only alternative for domestic lighting.     

Design, construction and study of a hybrid solar food processor in the climate of Costa Rica

During the last 25 years, the author has designed, constructed, studied and promoted solar oven, hybrid solar/electric oven, solar oven cum drier, solar cooker cum water heater and solar still. In different parts of the world, solar cookers have been made, studied, patented, however, their real uses are very limited due to many reasons—unstable climate, economic, cultural, social and single use, etc. In order to overcome part of the problems mainly the last one, author has recently designed one hybrid food processor (multi-purposes device) and studied various technical and practical aspects. It has been used for cooking, heating/pasteurizing water (to inactivate microbes) and distillation of small quantity of water (to remove different minerals) and drying domestic products (fruits, vegetables and condiments/herbs, etc.). For more than three years of use, author has found this to be a useful device, mainly from convenience, fuel saving, economic and also from ecological point of view. This device can be used at any time and for different uses but with the reduced consumption of conventional fuel.     

Bangladesh energy resources and renewable energy prospects

Bangladesh is a low-economy country with annual commercial energy consumption of only 35 kgOE/capita. Fossil fuel reserves are meagre; about 80% of the total energy supply comes from biomass. The fuel import bill is ~ 70% of total export earnings. Solar and wind energy have bright prospects for parts of the country where natural gas is not available and the cost of electricity, generated from oil-fired units, is high. Solar energy is abundant while wind speeds are high in some coastal areas. For rural electrification, the high cost of distribution lines makes solar electricity viable for remote locations, while wind machines may be set up in coastal areas.     

Present and prospective role of bioenergy in regional energy system

Bioenergy is the energy released from the reaction of organic carbon material with oxygen. The organic material derived from plants and animals is also referred to as biomass. Biomass is a flexible feedstock capable of conversion into solid, liquid and gaseous fuels by chemical and biological processes. These intermediate biofuels (such as methane gas, ethanol, charcoal) can be substituted for fossil based fuels. Wood and charcoal are important as household fuels and for small scale industries such as brick making, cashew processing etc. The scarcity of biofuels has far reaching implications on the environment. Hence, expansion of bioenergy systems could be influential in bettering both the socio-economic condition and the environment of the region. This paper examines the present role of biomass in the region’s (Uttara Kannada District, Karnataka State, India) energy supply and calculates the potential for future biomass provision and scope for conversion to both modern and traditional fuels. Based on the detailed investigation of biomass resource availability and demand, we can categorise the Uttara Kannada District into two zones (a) Biomass surplus zone consisting of Taluks mainly from hilly area (b) Biomass deficit zone, consisting of thickly populated coastal Taluks such as Bhatkal, Kumta, Ankola, Honnavar and Karwar. Fuel wood is mainly used for cooking and horticulture residues from coconut, arecanut trees are used for water heating purposes. Most of the households in this region still use traditional stoves where efficiency is less than 10%. The present inefficient fuel consumption could be brought down by the usage of fuel efficient stoves (a saving of the order of 27%). Availability of animal residues for biogas generation in Sirsi, Siddapur, Yellapur Taluks gives a viable alternative for cooking, lighting fuel and a useful fertiliser. However to support the present livestock population, fodder from agricultural residues is insufficient in these Taluks. There is a need to supplement the fodder availability with fodder crops as successfully tried in Banavasi village by some progressive farmers.     

Changes from traditional solid fuels to clean household energies – Opportunities in emission reduction of primary PM2.5 from residential cookstoves in China

Household biomass and coal use is an important source of PM_2.5 emission in China due to low efficient burnings and large consumptions. Primary PM_2.5 emissions for different fuels are compared based on a compilation of data from emission measurements of Chinese cookstoves in literature. The burning of pellets had low PM_2.5 emissions at 0.42 and 0.18 g MJ_d⁻¹ for straw and wood pellets, respectively. There would be an emission reduction of about 80% compared to ordinary raw biomass fuel burning for cooking. The average emissions of PM_2.5 per useful energy delivered were 0.10 and 0.28 g MJ_d⁻¹ for anthracite briquette and chunk, but as high as 1.2 and 3.2 g MJ_d⁻¹ for bituminous briquette and chunk, respectively. Coals burned in the form of briquette may lower PM_2.5 emission by 60% compared to the burning of raw chunk. The adoption of improved high efficiency cookstoves would have a comparable reduction in primary emissions compared to a fuel switch. Gas should be promoted for cooking as primary PM_2.5 emissions are 1,2 orders of magnitude lower compared to those for solid fuels. More emission measurements and fuel consumption survey are needed to fill data gap and to support interventions of advanced fuel–stove combinations.     

Solar-assisted smokehouse for the drying of natural rubber on small-scale Indonesian farms

Natural rubber in Indonesia is mainly produced by smallholder farmers and—being the highest foreign currency generating agricultural commodity—is of great importance for the Indonesian economy. Nevertheless, due to the lack of appropriate dryers, more than 80% of the total production has to be sold as low-grade Standard Indonesian Rubber (SIR) for a relatively low price.In order to improve the product quality, a solar-heated rubber sheet dryer was developed. It consists of a flat-plate solar air heater connected to a drying chamber. Part-recirculation of the exhaust air leads to the desired drying air temperature of 45–60°C and results in a significant reduction of the drying time. To enable drying independent of weather conditions, a biomass furnace was incorporated underneath the drying chamber.The tests have shown that during the rainy season, 320 kg of sheets can be uniformly dried to the required moisture content of 0.5% within 5 days. Compared with conventional smokehouses, the firewood consumption could be considerably reduced, from 1.0–1.5 kg per kg dry rubber to 0.3 kg when producing Ribbed Smoked Sheets (RSS). A further reduction can be expected by optimization of the heating intervals. During favourable weather conditions Air Dried Sheets (ADS) can be produced within 6–7 days without supplemented heat. The quality of the RSS and ADS fulfills the international standards.The simple design of the solar-assisted smokehouse allows local production and—after further improvements—seems to be an economical alternative for farmer groups or nucleus estates.     

Evaluation of cooking energy cost,efficiency, impact on air pollution and policy in Nigeria

This study evaluated the cooking energy costs and efficiencies, the air pollution impacts of cooking energy consumption and the impact of the energy policy in the cooking energy sector in Nigeria. Water boiling and cooking experiments using the common cooking energy sources (fuel wood, kerosene, liquefied petroleum gas (LPG) and electricity) and common food items (water, yam and beans) were carried out. Energy surveys were carried out to determine the cooking energy use patterns in the urban and rural areas. It was found that fuel wood is the least expensive cooking energy source and LPG is the most expensive. Energy use efficiencies for boiling water were estimated at 25%, 46%, 73%, 79%, 66% and 90% for fuel wood, kerosene, gas, electric immersion coil, electric heating coil and electric hot plate, respectively. Energy intensity was found to be a comparative measure of energy efficiency. The impacts of air pollution from household cooking suggested a possibility of significant air pollutants contribution to the ambient environment using any of the energy carriers considered except electricity. The cooking energy use patterns showed that fuel wood is the predominant energy source for cooking in the rural areas while kerosene is the predominant energy source in the urban areas, revealing that the energy policy in the country had made no impact in the cooking energy sector. Recommendations for improving the energy supply situation were given and for removing the barriers that prevent the implementation of the recommendations.     

Assessment of wood fuel use for energy generation in Lithuania

The paper investigates possibilities to use solid biomass (wood) resources. It provides detailed analysis on distribution of Lithuanian wood resources and evaluates possibilities to develop the use of above resources for heat and power generation. European Union as well as Lithuanian legislation declares promotion measures for wood as fuel for energy generation. Legal documents suggest implementation via subsidizing of raw material for production of wood chips for boiler-houses and adopting specific promotion program for the use of forestry biomass for boiler-houses according to which the difference between price and costs should be subsidized for producers of such raw material.Directive 2009/28/EB obligates separate countries to develop National Renewable Energy Action Plans (NREAP), which would provide specific promotion schemes and target indicators for each year (up to year 2020). According to this Directive the EU RES share in final energy consumption should reach 20%, and for Lithuanian this share should be no less than 23%, while district heating systems should use no less than 70%. At present the total capacity of wood-chip-fueled boilers reached above 476.1 MW. No series obstacles can be seen for extension of wood fuel use. The renewable energy compromise 18.1% of primary energy annual gross inland consumption and cut of the CO₂ emissions about 6% compared with the level on 1990. According to the Kyoto Protocol Lithuania must reduced green gas emissions 8% in the period 2008–2012. These goals can be realised by increasing of the use of biomass as fuel for the energy production.     

Solar cooker with latent heat storage systems: A review

Cooking with the sun has become a potentially viable substitute for fuel-wood in food preparation in much of the developing world. Energy requirements for cooking account for 36% of total primary energy consumption in India. The rural and urban population, depend mainly, on non-commercial fuels to meet their energy needs. Solar cooking is one possible solution but its acceptance has been limited partially due to some barriers. Solar cooker cannot cook the food in late evening. That drawback can be solved by the storage unit associated with in a solar cooker. So that food can be cook at late evening. Therefore, in this paper, an attempt has been taken to summarize the investigation of the solar cooking system incorporating with phase change materials (PCMs).     

Optimal sizing of a solar–biogas-based cooking system for a cluster of villages

Energy supplies particularly in remote and far-flung rural areas are in pathetic situation. Leave aside other needs, most of the rural communities still use wood as a source of energy for cooking. Burning of wood is not only an inefficient method, but also hazardousness for the person working on the stove. People have been working for cleaner and efficient means of cooking for decades. Solar cooker- and biogas-based cook stoves are two of the successfully implemented technologies in this area. Although solar cooker requires no maintenance, the initial investment is quite high for a cluster of villages. In addition to this, the intermittency involved in solar energy makes this an unreliable source.

In this paper, a cluster of villages of Narendra Nagar block of Tehri Garhwal district of Uttarakhand, India, has been studied in terms of their thermal requirements. The potential of solar energy and biomass energy has been estimated. An integrated solar–biogas system has been proposed to satisfy this cooking demand. To obtain the optimal sizes of solar cooker and biogas generator, MATLAB codes have been developed. It was found that this system is more economical and much reliable than the other two cases.     

Modelling of energy usage for the refining of ethanol from corn

A mathematical model is developed and presented for calculating the energy usage and costs for the dry milling corn-ethanol production process. The model is formulated into a spreadsheet to facilitate the study of the process. While considering the whole process, the model focuses on the primary energy-consuming cooking and distillation processes. This model is a feed-backwards model, which means process input requirements are calculated based on user-entered values for total annual plant production and various process parameters. Based on these input requirements, the total energy usage and the cost and amount of fuel used during the process are calculated. The accuracy of the model was verified through comparisons between modelling results and published data. This model can be used as a source for investigating other potential energy sources, such as the incorporation of solar energy and wind energy, for use in the ethanol production process.