Solid-fuel household cook stoves: Characterization of performance and emissions

In this study, 14 solid-fuel household cook stove and fuel combinations, including 10 stoves and four fuels, were tested for performance and pollutant emissions using a WBT (Water Boiling Test) protocol. Results from the testing showed that some stoves currently used in the field have improved fuel efficiency and lower pollutant emissions compared with traditional cooking methods. Stoves with smaller-mass components exposed to the heat of fuel combustion tended to take lesser time to boil, have better fuel efficiency, and lower pollutant emissions. The challenge is to design stoves with smaller-mass components that also have acceptable durability, affordable cost, and meet user needs. Results from this study provide stove performance and emissions information to practitioners disseminating stove technology in the field. This information may be useful for improving the design of existing stoves and for developing new stove designs. Comparison of results between laboratories shows that results can be replicated between labs when the same stove and fuel are tested using the WBT protocol. Recommendations were provided to improve the ability to replicate results between labs. Implications of better solid-fuel cook stoves are improved human health, reduced fuel use, reduced deforestation, and reduced global climate change.     

Energy performance of wood-burning cookstoves in Michoacan, Mexico

There have been few detailed assessments of the actual impacts of improved stove interventions in rural communities, although many improved stove projects have reported overall efficiencies from tests in simulated kitchens using water-boiling tests (WBTs). This paper presents an integrated energy evaluation of the Patsari cookstove, an efficient wood-burning cookstove developed in Mexico that has recently obtained international recognition, in comparison to traditional cookstoves in rural communities of Michoacan, Mexico. The evaluation uses three standard protocols: the WBT, which quantifies thermal efficiency and firepower; the controlled cooking test (CCT), which measures specific energy consumption associated with local cooking tasks, and the kitchen performance test (KPT), which evaluates the behavior of the stoves in-field conditions and estimates fuel savings. The results showed that the WBT gave little indication of the overall performance of the stove in rural communities. Field testing in rural communities is of critical importance, therefore, in estimating the benefits of improved stoves. In the CCT for tortilla making, the main cooking task in Mexican rural households, Patsari stoves showed fuelwood savings ranging from 44% to 65% in relation to traditional open fires (n=6; P<0.05). These savings were similar in magnitude to the average energy savings from KPT before and after Patsari adoption of 67% (n=23; P<0.05) in rural households exclusively using fuelwood. Similar energy savings of 66% for fuelwood and 64% for LPG, respectively, were also observed in households using mixed fuels. With sound technical design, critical input from local users and proper dissemination strategies, therefore, improved stoves can significantly contribute to improvements in the quality of life of rural people with potential benefits to the surrounding environment.     

What makes people adopt improved cookstoves? Empirical evidence from rural northwest Pakistan

Large dependence of the world population on biomass fuels for domestic energy consumption is one of the major anthropogenic causes of deforestation worldwide. The use of biomass in inefficient ways in rural areas increases fuelwood demand of a household. Development of the improved biomass stove programs in the 1970s has been one of the efforts to reduce burden on biomass resource base through reliable and efficient methods of energy consumption. However, despite having multiple economic, social, environmental, and health benefits; the improved stove dissemination programs failed to capture worldwide recognition. A wide array of socio-cultural, economic, political, and institutional barriers contributes to the low adoption rate of such programs. Drawing on field work surveys in rural northwest Pakistan, this paper provides empirical evidence of individual, household, and community level variables that play a vital role in the adoption of improved cookstoves. The study is based on primary data collected from 100 randomly selected households in two villages of rural northwest Pakistan. Using regression analysis, the study depicts that education and household income are the most significant factors that determine a household willingness to adopt improved biomass stoves. The study concludes that the rate of adoption could substantially be improved if the government and non-governmental organizations (NGOs) play a greater role in overcoming the social, economic, cultural, political, and institutional barriers to adopting improved cooking technologies.     

Stoves or sugar? Willingness to adopt improved cookstoves in Malawi

Malawi has set a target of adoption of two million improved cookstoves (ICS) by 2020. Meeting this objective requires knowledge about determinants of adoption, particularly in rural areas where the cost of traditional cooking technologies and fuels are non-monetary, and where people have limited capacity to purchase an ICS. We conducted a discrete choice experiment with 383 households in rural Malawi asking them if they would chose a locally made ICS or a package of sugar and salt of roughly equal value. Six months later, we assessed adoption and stove use patterns. Sixty-six percent of households chose the ICS. We find that having a larger share of crop residues in household fuel supply, awareness of the environmental impacts of woodfuel reliance, time the primary cook devotes to collecting fuelwood, and peer effects at the village-level increase the odds of choosing the ICS. Having a large labor supply for fuelwood collection and experience with a non-traditional cooking technology decreased the odds of choosing the ICS. In a rapid assessment six months after stoves were distributed, we found 80% of households were still using the ICS, but not exclusively. Our findings suggest considerable potential for wide-scale adoption of low cost ICS in Malawi.     

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.     

Improved stoves in developing countries: A critique

Improved stoves have largely failed to achieve widespread dissemination in developing countries for a number of reasons. Improved stoves were not necessarily more efficient than traditional designs nor were they always smokeless. Improved stove programmes emphasize fuel economy whilst stove users regard versatility and the ability to cook quickly as being more important. Other concerns of villagers such as water supplies and income-generating technologies may have a higher priority than the supply of traditional cooking fuels. Moreover, stove programmes are unlikely to significantly reduce deforestation. The likely effects of stove programmes could have been determined and a number of problems avoided had these projects been appropriately monitored.     

Financial analysis of cooking energy options for India

A financial analysis of cooking energy options is attempted for India using data from a field study and real costs and prices. The fuels considered are; fuelwood, kerosene, biogas, liquid petroleum gas (LPG) and electricity. Traditional and efficient devices and different discount rates are used in the analysis. Financial analysis for rural areas shows that the efficient Astra-stove using wood is the least cost option and biogas, which is the only quality fuel option for rural areas, is the most expensive option. The subsidised kerosene option is cheaper than wood in the traditional stove. The ranking of options from low to high costs is from fuelwood to kerosene to LPG to biogas. In the urban situation, the subsidy on kerosene distorts the energy ladder. Kerosene is the low cost fuel option, and fuelwood in the traditional stove is among the most expensive options. The existing subsidies on kerosene, LPG and electricity seem to benefit middle and high income groups, particularly in urban areas. Low income households in urban and rural areas are forced to use fuelwood in traditional stoves, which is not only a low quality fuel but is also a high cost cooking energy option. The efficiency of the device is shown to be a crucial factor in determining the cost of using a fuel. Low income households are disadvantaged, as they use traditional low efficiency wood stoves. A need to alter energy policies to promote quality fuels and efficient devices in an accessible way to low income households is highlighted.     

Design and performance evaluation of a 5 kW producer gas stove

The paper addresses the studies of a wood gas stove in meeting cooking energy requirement using biomass gasification. The stove works on natural draft mode. The thermal efficiency of the stove was recorded at about 26.5% and it can be started, operated and stopped with very low emissions. It can use a wide variety of biomass fuels. The produced wood gas burns with a blue flame like liquid petroleum gas with a flame temperature of 736 °C. The design criteria, safety measures and operating procedure of wood gas stoves are presented in this paper.     

Performance evaluation of three types of forced draft cook stoves using fuel wood and coconut shell

Many cook stove programs implemented in South Asia and Africa were aimed at reducing fuel wood consumption and pollutants through the use of improved cook stoves. The research work presented in this paper is focused on evaluation of improved cook stoves with respect to thermal efficiency and emission levels. Since the type of biomass fuel varies in different geographical regions, the improved cook stoves must be compatible to use different types of fuel. The present research work is aimed at evaluating three types of forced draft cook stove with two types of biomass fuels. Water boiling tests were conducted to evaluate the stove performance with respect to efficiency and fuel flexibility. The findings of the study are used to evaluate the stove's performance with respect to fuel flexibility, efficiency and user acceptance. The performance results of three types of forced draft stoves tested with fuel wood and coconut shell are presented in this research paper.     

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.     

The economics of improved charcoal stoves in Kenya

Charcoal for cooking is a major expenditure for urban households in Kenya and improved stoves can reduce fuel costs by at least 25%. The author relates how, although an improved stove is more expensive than a traditional stove, the payback period is short and an improved stove also lasts longer. The benefits to society of a programme to encourage small-scale, informal sector production of charcoal stoves are seen to be large, even after accounting for the administrative costs. Such a programme may also provide limited employment and income gains for producers. The environmental impacts may be significant because of the energy loss in converting wood to charcoal and the fact that charcoal is usually made from felling whole trees.     

The “hood method” of measuring emissions of rural cooking devices

The potential for the forced extraction of flue gases to change the combustion characteristics of unvented biomass-burning cooking devices is assessed. The performance of three stoves with different air inlet characteristics was measured using three hood extraction rates. These extraction rates were selected between the boundaries of being sufficiently low to have no visual impact on a flame at the height of the stove and of being high enough to capture all emissions. Fire power, fire temperature and thermal efficiency was found not to be affected by the extraction. Sulphur dioxide and Total Suspended Particulates show no significant effect of extraction at a 95% confidence level. A measurable influence of extraction on carbon monoxide emissions was detected, but this was considerably smaller than the effect of the stove. There was no detectable interaction between stove type and extraction level indicating that the influence of the extraction on emissions is independent of the type of stove. It is thus possible to use an extraction hood to compare emissions from different stoves provided the extraction level does not change between tests and falls between the boundaries investigated in this study. The method for setting extraction rates used here is simple and effective and requires no complex measurement techniques. It is feasible that comparisons between emissions from different cooking devices may be made without the aid of air-flow measurements thereby significantly simplifying and reducing the cost of emission assessment in the stove design process.     

The emissions from a space-heating biomass stove

In this paper, the flue gas emissions of carbon monoxide (CO), nitrogen oxides (NO_X), sulphur dioxide (SO₂) and soot from an improved space-heating biomass stove and thermal efficiency of the stove have been investigated. Various biomass fuels such as firewood, wood shavings, hazelnut shell, walnut shell, peanut shell, seed shell of apricot (sweet and hot seed type), kernel removed corncob, wheat stalk litter (for cattle and sheep pen), cornhusk and maize stalk litter (for cattle pen) and charcoal were burned in the same space-heating biomass stove. Flue gas emissions were recorded during the combustion period at intervals of 5 min. It was seen from the results that the flue gas emissions have different values depending on the characteristics of biomass fuels. Charcoal is the most appropriate biomass fuel for use in the space-heating biomass stoves because its combustion emits less smoke and the thermal efficiency of the stove is approximately 46%.     

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.     

Wood cookstoves in Fiji

In almost all rural areas of the Pacific Island Nations cooking is predominantly accomplished using wood fires. Many attempts have been made by aid agencies and benevolent organizations to introduce improved woodstoves. The main reasons were to conserve wood fuel and to provide a healthier environment in the kitchen area. The present paper details a study of eight rural villages in Fiji to investigate cooking habits and wood stove cooking experience. The results suggest that in actual practice stoves are not more efficient than open fires and that the management of the fireplace is the key to overall fuel efficiency. More emphasis should be placed on providing more accessible fuel by concentrating on fuelwood lots close to the villages and to looking at the kitchen environment as an integrated whole and not just focussing on the cooking stove.     

Health and climate benefits of cookstove replacement options

The health and climate impacts of available household cooking options in developing countries vary sharply. Here, we analyze and compare these impacts (health; climate) and the potential co-benefits from the use of fuel and stove combinations. Our results indicate that health and climate impacts span 2 orders of magnitude among the technologies considered. Indoor air pollution is heavily impacted by combustion performance and ventilation; climate impacts are influenced by combustion performance and fuel properties including biomass renewability. Emission components not included in current carbon trading schemes, such as black carbon particles and carbon monoxide, can contribute a large proportion of the total climate impact. Multiple ‘improved’ stove options analyzed in this paper yield roughly equivalent climate benefits but have different impacts on indoor air pollution. Improvements to biomass stoves can improve indoor air quality, which nonetheless remains significantly higher than for stoves that use liquid or gaseous hydrocarbons. LPG- and kerosene-fueled stoves have unrivaled air quality benefits and their climate impacts are also lower than all but the cleanest stoves using renewable biomass.     

Utility assessment of parabolic solar cooker as a domestic cooking device in India

The needs of cooking energy in households can be supplemented by parabolic solar cooker (PSC). Policy for energy substitution by renewables has to consider many conflicting socio-economic issues. To know the perceptions of decision-makers and users, a survey is conducted to evaluate nine cooking energy devices available in India. Energy technology issues, economics, environmental/social, behavioral and commercial issues are considered for the evaluation. Thirty criteria are considered under these five aspects for pair-wise comparison of the devices. Additive Multi-Attribute Utility Theory (MAUT) is employed to evolve ranking of selected devices. It is found that Liquefied Petroleum Gas (LPG) stove is the most preferred cooking device, followed by microwave ovens and kerosene stoves. PSC has occupied fifth rank amongst the devices. A sensitivity analysis is also carried out for identifying potential areas of improvement for PSC, which forms a basis for policy interventions required for its better dissemination in India.     

Improved stoves in India: A study of sustainable business models

Burning of biomass for cooking is associated with health problems and climate change impacts. Many previous efforts to disseminate improved stoves – primarily by governments and NGOs – have not been successful. Based on interviews with 12 organizations selling improved biomass stoves, we assess the results to date and future prospects of commercial stove operations in India. Specifically, we consider how the ability of these businesses to achieve scale and become self-sustaining has been influenced by six elements of their respective business models: design, customers targeted, financing, marketing, channel strategy, and organizational characteristics. The two companies with the most stoves in the field shared in common generous enterprise financing, a sophisticated approach to developing a sales channel, and many person-years of management experience in marketing and operations. And yet the financial sustainability of improved stove sales to households remains far from assured. The only company in our sample with demonstrated profitability is a family-owned business selling to commercial rather than household customers. The stove sales leader is itself now turning to the commercial segment to maintain flagging cash flow, casting doubt on the likelihood of large positive impacts on health from sales to households in the near term.     

Clean fuel-saving technology adoption in urban Ethiopia

The heavy dependence and inefficient utilization of biomass resources have contributed to the depletion of forest resources in Ethiopia, while the use of traditional cooking technology has also been linked to indoor air pollution and poor health. In response, the government and other institutions have pushed for the adoption of new cooking technologies, with limited success. This research examines the reasons underpinning the lack of widespread adoption, via duration analysis, correlating the speed of adoption of Mirte and Lakech cook stoves – two examples of new cooking technologies – in urban Ethiopia to socioeconomic factors. According to the duration analysis, adoption rates have steadily increased over time, while economic factors, such as product price, household income and household wealth, are, for the most part, important determinants of adoption behavior. There is also evidence that the availability of substitute technologies tends to hinder adoption, and that there are large regional differences in adoption rates, suggesting the need for a more detailed regional analysis of adoption decisions.     

Sustainable energy development strategies in the rural Thailand: The case of the improved cooking stove and the small biogas digester

This paper presents the strategies to overcome barriers to the adoption of improved cooking stove (ICS) and small biogas digester (SBD) technologies in Thailand. Firstly, to obtain the appropriate strategies to implement the ICS and the SBD, a pattern of energy consumption in the residential sector is investigated. Then the potential of reduction of energy consumption and corresponding emissions by the ICS and the SBD is assessed. The identification and ranking of barriers to the adoption of the ICS and the SBD technologies are also investigated. In this study the Long-range Energy Alternatives Planning System (LEAP) model is used to assess the energy consumption and the corresponding emissions reduction. Then, the Analytic Hierarchy Process (AHP) model is used to identify and rank the barriers. Results from the LEAP model show that the cumulative total energy consumption and corresponding emissions reductions during the period 2002–2030 by the ICS are 27,887.7 ktoe and 10,041.0 thousand tonnes of CO₂ equivalent, respectively. An average emissions reduction cost per tonne of CO₂ equivalent per year is US$ 0.95 for a fuel wood cooking stove and US$ 0.35 for a charcoal cooking stove. Regarding the SBD, the cumulative total liquefied petroleum gas (LPG) consumption reduction and CO₂ mitigation are 5780.9 ktoe and 1548.8 thousand tonnes of CO₂ equivalent during the period 2002–2030, respectively. Results from AHP analysis of ranking of barriers show that the three most important barriers in the adoption of the ICS are (i) high investment cost, (ii) lack of information, and (iii) lack of financial sources. For the SBD, the three most important barriers are (i) high investment cost, (ii) lack of financial sources, and (iii) lack of experts and skilled manpower. The sustainable energy triangle strategy (SETS) is implemented to overcome barriers in the adoption of the ICS. Results show that the traditional cooking stoves are successfully replaced (more than 20% per year). Regarding the SBD, the biogas pool project (BPP) is implemented to resolve the over supply of biogas. Results also show that the BPP is a proper strategy.