Reimagining Household Cooking: A Critical Assessment of Improved Cookstoves Implementation for Sustainable Development

Abstract

Food is one of the most important components for the survival of humans. Women suffer the most impacts of the cooking harmful gases and particulate matters that are 2.5 microns (PM2.5) or less such as PM10. Improved cookstoves are used to reduce firewood consumption, lower the smoke released from the kitchen, help women improve their health, and conserve native trees in the area. Sustainably managed biomass, unlike the burning of fossil fuels, is considered carbon neutral since it does not contribute to the overall carbon emissions in the atmosphere. In 2015, the United Nation mentioned 17 Sustainable Development Goals (SDGs) to be achieved by 2030. This research aims to assess an improvement in the cookstove implementation level within the clean development, by reducing the carbon emissions following the Indian perspective for the program of better cookstoves.

1 Introduction

Clean cooking provides a highly effective and affordable approach to tackle the urgent problems of pollution, climate change, and biodiversity loss. Around 2.4 billion individuals, which accounts for approximately one-third of the global population, depend on inefficient stoves or open fires fuelled by coal, biomass (like wood, animal dung, and crop waste), and kerosene for their cooking needs. In 2020 alone, this practice causing household air pollution (HAP), which was responsible for approximately 3.2 million deaths, including over 237,000 deaths of children under 5 years [1].

Inefficient and frequently lacking in appropriate ventilation, traditional cooking stoves consume the majority of solid fuels. One of the primary advantages of biomass is to be a renewable energy source. Properly managed biomass is considered carbon-neutral since it does not contribute to an overall increase in carbon emissions in the atmosphere, unlike burning fossil fuels [2].

The production and consumption of fuelwood and charcoal contribute to the release of 1–2.4 billion metric tons of greenhouse gases (GHGs) in the form of carbon dioxide equivalents (CO2e) annually. Improper use of fuelwood is a significant human activity that degrades the environment and harms forests. The primary contributors to greenhouse gas (GHG) emissions were the burning of wood and diesel. Moreover, the incomplete combustion of firewood releases substantial amounts of black carbon (soot) and carbon-based greenhouse gases. In rural areas of India, approximately 90% of the population lacks access to modern fuels, leading to a significant annual usage of 150 million tonnes of biomass for cooking purposes [3].

Eliminating the use of solid fuels and kerosene for cooking will help to address environmental degradation and mitigate global warming that reduce smoke exposure impacts (3rd Sustainable Development Goal, SDG3). Furthermore, this clean cooking can be used to increase productivity impacts SDG8 on economic growth by saving time and money, in addition to many of the other SDGs, which established by the United Nations on having access to clean, modern, sustainable, and affordable energy [4].

2 Methodologies

The “improved” cooking technology consume less fuel and smokeless from incomplete combustion. The co-benefits include enhanced fuel savings, enhanced health outcomes, reduced indoor air pollution, and positive environmental effects. Solid-fuel stoves, or Improved Cookstoves (ICS), are produced to be more effective than conventional biomass technology, which saves fuel, and reduces particle’ emissions. Recent studies, such as Project Surya, have demonstrated that improved forced draft stoves can reduce Black Carbon (BC) concentrations nearly twice as much as natural draft stoves in controlled kitchen environments, and contribute to climate mitigation efforts [5]. By reducing the amount of biomass required for cooking, these stoves alleviate pressure on forests and other vegetation sources promote sustainable resource management techniques, and help to conserve natural resources. Furthermore, it offer significant health advantages by reducing indoor air pollution (IAP) that associated with conventional cooking methods. The inclusion of grating in ICS is a vital feature that enhances combustion and efficiency. Typically, a 20 × 20 cm cast iron grating is attached at the bottom of the ICS, with a channel generated beneath it to facilitate airflow into the cookstove. This design promotes complete combustion of firewood, and reduces smoke emissions. Furthermore, the unimpeded airflow within the channel improves combustion efficiency. Cookstoves are categorized in the literature based on various factors, including the extent of modifications, performance requirements in terms of efficiency and emissions, and the type of fuel used [6].

Cookstove projects can lead to the generation of two types of carbon credits: Certified Emissions Reduction (CER) credits and Voluntary Emissions Reduction (VER) credits. These credits are recognized under the Kyoto Protocol, which is overseen by the United Nations Framework Convention on Climate Change (UNFCCC), which is responsible for issuing CER credits. Both types of projects undergo a rigorous testing and validation process to demonstrate their ability to offset a certain number of emissions [7]. Under the Clean Development Mechanism (CDM), two different approaches are available for cookstove projects AMS II.G and AMS I.E. The AMS II.G is applicable when a more efficient cookstove introduced to reduce the consumption of non-renewable biomass. Furthermore, the AMS I.E approach applies when renewable technologies, such as biogas or solar cookers, are implemented to replace the use of non-renewable biomass [8]. A comparison between those two approaches is presented in Table 1.

Table 1. CDM-AMS II.G versus CDM-AMS I.E.

This methodology measures the reduction of emissions by calculating the amount of nonrenewable biomass or fossil fuels that are consumed less. For non-renewable biomass, the methodology is the same as that outlined in AMS-II.G. Such reduction in a certain year (ERy) is related to the tons weight saved for the biomass (By,vings,i,j) per each project i and batch j. The percentage of woody biomass (fNRB,y) with some unpredictability reduction (ud), which considered as not renewable, should be determined, in addition to the CO₂ (EFwf,CO2) and the non- CO₂ (EFwf,non CO2) emission factors (t CO₂/TJ). It can be calculated through the following equation:

$$ ER_{y} = \sum\nolimits_{{\text{i}}} {\sum\nolimits_{{\text{j}}} {B_{y,savings,i,j} } \times N_{0,i,j} \times n_{y,i,j} \times {\upmu }_{{\text{y}}} \times f_{NRB,y} \times NCV_{biomass} \times (EF_{wf,co2} } + EF_{wf,nonco2} ) \times Adj_{LE} \times (1 - u_{d} ) $$

(1)

where:

NCVbiomass is the net calorific value of the non-renewable woody biomass (replaced or reduced). N0, is the project devices (i) and batch (j) assigned. However, ny,i,j is the assigned remain operating ratio of the same project devices and batch within the same year, using certain adjustment factor (μy) during the same year, and another adjustment factor (AdjLE) that is related to the leakage for the non-renewable woody biomass saved.

The Chetak cookstove is specifically designed to burn dung cakes, firewood, and agricultural waste as fuel. To accommodate small utensils, the Chetak cookstove has undergone certain modifications, with a thermal efficiency of 21% (Fig. 1). Udairaj cookstove, an enhanced biomass cookstove has two pots, with the first having a diameter of 17 cm, and 15 cm for the second pot. The wood burns efficiently and safely in this cookstove. It offers a thermal efficiency of 25%, ensuring effective utilization of the fuel’s heat [9].

The Patsari cookstove incorporates several design elements to enhance its efficiency and reduce smoke emissions [10]. The design of the Patsari cookstove includes tunnels that lead to secondary chambers with smaller combustion areas. These secondary chambers are used for low-power cooking tasks. The combustion gases are expelled through these tunnels, contributing to improved combustion efficiency and reducing fugitive smoke emissions. This design ensure to make it more efficient and environmentally friendly [11].

The Lakech and the Merchaye stoves offer options for efficient charcoal cooking, but with some differences in their specifications and characteristics. The Lakech Cookstoves have been estimated to have a CO2e (carbon dioxide equivalent) emission mitigation potential of 0.14 tCO2e (tons carbon dioxide equivalent) per stove per year. This indicates the potential reduction in greenhouse gas emissions compared to traditional cooking methods. However, the Merchaye stove has a higher estimated CO2e emission mitigation potential compared to the Lakech stove, with a value of 0.33 tCO2e per stove per year [12].

By fostering the processes of gasification (the conversion of solid biomass into combustible gases) and pyrolysis (the decomposition of organic material by heat in the absence of oxygen), TLUD and IDD gasifier stoves are made to maximize the burning of biomass fuel, such as wood or agricultural waste (Fig. 2, 3, 4 and 5). These stoves’ Map Predicted Fire (MPF) enables the production of combustible gases to produce cooking heat. Top-lit up-draft gasifier stoves are highly regarded for their ability to effectively burn the volatile gases produced by biomass fuels when heated in the absence of oxygen. These stoves are designed with reduced primary air inlets to allow for a natural draft, which pulls the gases up the chimney. This combustion process ensures that the gas fuels would be released into the atmosphere with lower emissions. In addition, it improves indoor air quality, benefiting the health and well-being of users. TLUDs, with their small fuel batch sizes and moderate burn rates, offer exceptional fuel efficiency and minimal emissions during the combustion process. Additionally, TLUD stoves contribute to lower greenhouse gas emissions, aligning with environmental sustainability goals. Furthermore, their fuel efficiency lead to cost savings and better fuel economy in cooking methods [13].

Fig. 1.

Modified Single Pot Chetak Cookstove [9].

Fig.2.

Patsari wood-burning cookstove [10].

Fig. 3.

Lakech Cookstove [9].

Fig. 4.

Merchaye Cookstove [9].

Fig. 5.

Top-Lit Up-Draft Technology [13]

In performance studies of biomass cookstoves, various tests are commonly used to assess their effectiveness and efficiency in real-world cooking scenarios. Two commonly used tests are the Water Boiling Test (WBT) and the Kitchen Performance Test (KPT).

• (a) The Water Boiling Test (WBT) proposed to measure the emissions during cooking and to assess the stove uses fuel to heat water in a cooking pot. The main goal of the WBT is to evaluate the performance of various cookstoves by comparing them according to parameters like thermal efficiency (ηth) and emissions mass, furthermore, to make sure that these stoves adhere to the standards set by various governmental and non-governmental organizations. It is divided into three distinct phases: the cold-start high-power in which water is heated to room temperature, then brought to a boil in the second phase (the hot-start high-power), and simmering is the last phase (Fig. 6), which entails holding the boiling water at a temperature below 45 min (Fig. 7) [14].

Fig. 6.

Particulate Matter (PM), Pot temperature, and relative humidity during WBT [14]

Fig. 7.

CO₂ and CO emissions during WBT [14]

To assess the emissions performance of biomass cookstoves, during WBT, a Laboratory Emissions Monitoring System (LEMS) is often used (Fig. 8) that includes sensors for measuring carbon monoxide (CO), carbon dioxide (CO₂), and Particulate Matter (PM). These sensors play a crucial role in evaluating the emissions generated by the stove under test. The CO sensor in the LEMS utilizes an electrochemical cell with two electrodes to measure the amount of CO produced by the stove. The CO₂ sensor in the LEMS uses non-dispersive infrared technology to measure the amount of CO₂ produced by the stove. This sensor generates a voltage that corresponds to the CO₂ concentration, enabling the quantification of CO₂ emissions. The gravimetric system, which provides a direct measurement of PM concentration, measures total PM utilizing filter-based sampling in Fig. 8.

Fig. 8.

Laboratory Emissions Monitoring System with the Nozzle type Energy Efficient Cookstove mounted inside the metal hood [14]

The performance parameters of biomass cookstoves can be usefully revealed by emissions testing utilizing LEMS during water boiling tests. These emissions are significant considerations for assessing the environmental impact and possibility of decreasing Indoor Air Pollution (IAP) [14].

• (b) Kitchen Performance Test (KPT) is considered the major field-based technique for evaluating the stove improvements that affect household fuel use. The aim of this test is to study the impact of the improved stove(s) on fuel consumption in actual kitchen contexts of families and to assess qualitative elements of stove functionality through household surveys. It includes qualitative analyses of stove performance and user satisfaction in addition to quantitative measurements of fuel usage in order to meet these objectives [15].

2.1 Firepower (FP)

In biomass cookstoves, it is a thermal performance parameter that measures the amount of thermal energy generated in a given time period (kW). Firepower is calculated by dividing the amount of thermal energy produced (kJ) by the time taken to generate that energy (s). The firepower of a cookstove is an important characteristic as it represents its heating capacity (cooking efficiency and performance). A higher firepower indicates a larger heat output, which can result in faster cooking times. It is important to consider other thermal performance parameters such as specific fuel consumption, turndown ratio, as well as emission performance parameters such as emission factors of pollutants, to evaluate the overall performance of biomass cookstoves and their environmental impact [16].

2.2 Thermal Efficiency (Η)

It is a measure of how effectively it converts the energy generated during the combustion of biomass fuel into usable thermal energy for cooking. It is typically expressed as a percentage. It is evaluated by dividing the actual energy used by the pot and its contents for cooking by the firepower available due to the combustion of the fuel. This parameter is important since it reflects the efficiently of the cookstove in utilizing the energy from the biomass fuel for cooking. Higher thermal efficiency indicates a more efficient cookstove that is able to utilize more of the available energy for cooking, resulting in lower fuel consumption and reduced environmental impact [16].

2.3 Specific Fuel Consumption (SFC)

It measures the amount of dry fuel, typically expressed in grams, required to produce a specific unit of output. It is commonly reported as grams of fuel per kilogram of unit output (g/kg) by dividing the mass of the dry fuel used during the test by the mass of the unit output. The specific fuel consumption provides insights into the efficiency of a cookstove by quantifying the amount of fuel required to produce a given output. Lower values of SFC indicate better fuel efficiency, as less fuel is needed to achieve the desired cooking result [16].

2.4 Emission Factor (EF)

It evaluates the mass of a specific pollutant emitted per unit of fuel burned per kilojoule (kJ), or per megajoule (MJ) of energy released during cooking. It quantifies the pollutant emissions associated with the combustion of the fuel. The indoor concentration of a pollutant refers to the amount of exposure experienced by the user per cubic meter of air in the room or cooking area (ng/m3), which impact indoor air quality and the health of individuals exposed to them. Improved biomass cookstoves are known for their fuel efficiency. They can consume 20–50% less fuel compared to conventional biomass cookstoves, reduce lower emissions, and potentially improved indoor air quality. By using less fuel, improved cookstoves can also provide economic benefits by reducing fuel expenses for households and communities [16].

3 Result and Discussion

Despite variations in thermal efficiency, the Patsari stove exhibited several advantages over conventional stoves. During the low-power period, the Patsari stove demonstrated lower specific fuel usage compared to the high-power cold start phase. Furthermore, households that solely relied on fuelwood experienced an important decrease in energy consumption of when using the Patsari stove. It proves to be a more efficient and effective option, resulting in substantial energy savings for households relying on fuelwood.

Efficiency can be defined in various ways depending on different aspects of stove operation: Combustion efficiency, Heat transfer efficiency, Efficacy of the control, Pot effectiveness, and Efficiency of the cooking process.

3.1 Housing Improvements

Household exposure to air pollution can be considerably reduced by making improvements and adjustments to the housing. This can be accomplished by taking steps like building new or larger kitchen windows, adding flues and smoke hoods, widening roof spaces, elevating cooking surfaces to waist height, and dividing cooking rooms from other living areas. The promotion of home renovations for better health outcomes has typically been done through education and information dissemination. The success of housing renovation programs for bettering health in poor nations depends on the strict enforcement of building codes to ensure that changes are made to reduce exposure to indoor air pollution. Developing nations may achieve major advancements in housing conditions and reduce exposure to household air pollution by giving priority to the implementation of building standards, which will improve the health of their populations.

3.2 Behavioral Change

Recent analyses of behavioral modification programs have demonstrated that these tactics can dramatically lower the exposure of young children to household air pollution. Cooking outside, spending less time in the kitchen, keeping the door open while cooking, avoiding leaning over the fire while attending to cooking, not carrying children while cooking, and keeping kids away from the kitchen area are some of the advised behavioral changes to reduce exposure to household air pollution. To include household air pollution and clean cooking education in the training programs for frontline health workers, the Global Alliance for Clean Cookstoves (GACC) and other country alliances should contact the national health authorities. This may help raise public awareness of healthy cooking methods and encourage their adoption, which may minimize household exposure to air pollution and improve health outcomes in developing nations.

3.3 Carbon Offsets

Three billion people use traditional cookstoves or open flames to cook their food, which is a serious environmental and public health concern and a barrier to sustainable economic growth. Cleaner and more effective cooking technologies are available, but many households in underdeveloped nations cannot afford them or cannot get them in their local marketplaces. Businesses are now using carbon offsets or credits to help low-carbon development in developing nations, notably in the clean cooking industry, to address this problem. Cookstoves and fuels that are cleaner and more effective have the potential to achieve important annual reducing carbon dioxide (CO₂) emissions, in addition to enhancing livelihoods, quality of life, and health. Several SDGs could be aided by projects including efficient cookstoves. A more complete combustion is achieved by efficient cookstoves, which results in fewer emissions of methane and other pollutants, as well as using less fuel and/or switching to fuel that is less GHG-intensive, since few types of stoves meet the World Health Organization’s (WHO) definition of “clean” for carbon monoxide and particulate matter emissions.

4 Conclusion

The benefits of Improved Cookstoves (ICS) are two-fold, with positive impacts reported at both the household and regional levels. At the household level, users of ICS will have less smoke, reduced risk of burns, improved taste of food, and decreased expenditures on fuelwood. At the regional level, widespread adoption of ICS can contribute to mitigating forest degradation and result in significant savings of tons of CO₂ emissions per year, making ICS an effective and efficient means of securing carbon storage in forests. The effectiveness of cookstove has been evaluated into reducing greenhouse gas (GHG) emissions, measuring emissions reductions, reducing exposures to harmful pollutants, and improving health and well-being as highlighted in the Intergovernmental Panel on Climate Changes (IPCC) Sixth Assessment Report, which underscores the need to protect the environment and combat climate change.