In Sudan’s war-torn region of Darfur, women must either walk for hours to find firewood, risking attack every step of the way, or must trade precious food rations for the fuel. In 2005, the U.S. government asked Dr. Ashok Gadgil, Director of Lawrence Berkeley National Lab’s Environmental Energy Technologies Division, for a solution to this grave problem, and the foundation for Gadgil Lab – Stoves was laid. His team designed a fuel-efficient cookstove which is tailored to Darfur’s climate and cooking and requires less than half the fuel of traditional cooking methods, decreasing women’s exposure to violence while collecting firewood and their need to trade food rations for fuel.
Building on this work, Gadgil Lab – Stoves has extended its cookstove research and development to other regions as part of a larger effort to develop affordable and appropriate technology for the world’s poorest households. (2011 BERC Symposium poster)
Traditional cooking methods vary by location, but consist primarily of three-stone fires and rudimentary stoves made of mud or metal. These stoves tend to produce fast cooking times, but at a cost of large fuel usage, high pollutant emissions, and high excess heat.
There are three main categories of tests with which to compare stoves: water boiling, controlled cooking, and kitchen performance.
Water Boiling Test:
Controlled Cooking Test:
Kitchen Performance Test:
When pertaining to cookstoves, efficiency commonly refers to the amount of fuel needed to achieve a specific task and/or the amount of time that task takes.
In typical cookstove tests, researchers cook a fixed quantity of food or boil a fixed quantity of water on both the traditional cooking method and the improved stove. They compare the amount of fuel burned and the time needed to complete the task usage between the stoves to establish thermal efficiency and power output.
Efficiency tests allow researchers to:
- Predict the impact that the stove will have for women. The more efficient the stove, the less fuel the women will need to collect or buy for cooking.
- Determine the carbon emissions reductions due to fuel consumption that will result from substituting the stove for the traditional cooking method.
- Compare different design alterations under consideration to estimate the impacts of each change on the stove.
How much soot does the Berkeley-Darfur or Berkeley-Ethiopia Stove produce compared with the three-stone fire?
Researchers are currently characterizing the particles emitted by the traditional three-stone fire and the stoves and comparing the results. The results of these tests will be used to examine if the widespread implementation of advanced stoves such as the Berkeley-Darfur Stove and Berkeley-Ethiopia Stove might reduce undesirable impacts on climate change while also improving public health in developing nations. Black carbon and other soot particles emitted by cooking fires may be contributing to climate changes such as reduced precipitation and the melting of glaciers. See an evaluation of the Berkeley-Darfur Stove’s emissions and efficiency here.
Reducing CO2 emissions: Each stove saves a little over 1.5 metric tons of CO2 per year. According to the US Environmental Protection Agency, the average US car (traveling 12,000 miles per year and getting 20 mpg) emits 5.2 metric tons of CO2 per year. With stoves lasting an average of 5 years, each stove in the field reduces more CO2 emissions than removing an average US car off the road for an entire year.
How much are the stoves being used and how efficiently are the cooks feeding the firewood?
Efficiency tests allow researchers to understand how much firewood the stoves can save under ideal lab conditions; however, it’s also important to measure efficiency and use in the field. LBNL is studying small devices called Stove Use Monitors (SUMs) and plans to mount these small self-contained devices on Berkeley-Ethiopia Stoves to monitor and log stove temperature over several months of use. Periodically, a researcher in the field using a PDA or laptop computer will retrieve this information. The SUMs will enable LBNL to have a better understanding of how cookstoves are used. Information collected will be used to analyze the frequency of stove use, the “burn time” for each use, and the rate at which cooks are feeding firewood into the stove. Likewise, the data will help quantify the reduction in greenhouse gases resulting from the use of improved cookstoves.
How can we optimize how fast the stove gets hot?
The heating rate of the stoves is controlled by many factors. These include the type of wood used to fuel the stove, the size of the pieces of wood used, environmental factors like humidity levels, and how the wood is fed into the stove, among others. Researchers are working towards quantifying how these variables change the heating rates of the stove. These findings will help users of the Berkeley-Darfur Stove and Berkeley-Ethiopia Stove better control heat, make more efficient use of their fuel, and optimize stove functioning.
What portion of the heating energy in the wood is transferred to the pot?
Comparing the total potential heating energy in the wood to the amount of heat affecting the cooking pot ultimately helps researchers determine the efficiency of stoves. This research is being conducted with the help of a Bomb Calorimeter. These devices determine the amount of heat released through combustion of a small amount of wood fuel burning inside a sealed vessel (called the bomb). Oxygen is used to ensure complete combustion of the wood. The heat from this bomb vessel is then transferred to water that surrounds it on all sides. Very sensitive thermometers are used to measure the temperature rise of the water and determine the amount of heat released though the combustion process.
Since 2003, conflict in Darfur has killed at least 300,000 people and forced more than two million people from their homes, many of whom now live in large internally displaced persons (IDP) camps spread through the region. Although families in IDP camps receive food aid, they must still gather firewood for fuel. Due to the size of the IDP camps (some camps have more than 100,000 residents) and the desert-like terrain, wood is increasingly scarce. With deforestation, displaced women must walk up to seven hours to find a single tree, risking assault every step of the way. To avoid danger, some Darfuri women purchase wood from vendors… by selling the very food they need to feed their families. While the tangle of political and ethnic tensions underlying the Darfur conflict may seem beyond resolution, the solution to this one problem is clear: women in Darfur need a better stove.
Now Potential Energy, a nonprofit organization, has already distributed thousands of stoves in Darfur and aims to distribute a stove to every displaced Darfuri family.
When a team of scientists first embarked on a fact-finding mission in Darfur in 2005, they considered a variety of existing stoves as models for the Berkeley-Darfur Stove. Interviews, demonstration tests, and focus group discussions with Darfuri women revealed that a modified version of the Tara stove (first developed in India) would be most effective in reducing the amount of firewood needed for cooking.
Researchers are continually testing the Berkeley-Darfur Stove at the Lawrence Berkeley National Laboratory in Berkeley, California to better understand its impact.
- A tapered wind collar that increases fuel-efficiency in the windy Darfur environment and allows for multiple pot sizes.
- Wooden handles for easy handling.
- Metal tabs for accommodating flat plates for bread baking.
- Internal ridges for optimal spacing between the stove and a pot for maximum fuel efficiency.
- Feet for stability with optional stakes for additional stability.
- Nonaligned air openings between the outer stove and inner fire box to accommodate windy conditions.
- Small fire box opening to prevent using more fuel wood than necessary.
Ethiopia’s Energy consumption is predominantly based on biomass energy sources. An overwhelming proportion (94%) of the country’s energy demand is met by traditional energy sources such as fuel wood, charcoal, branches, dung cakes and agricultural residues. The balance is met by commercial energy sources such as electricity and petroleum. The most important issue in the energy sector is the supply of household fuels, which is associated with massive deforestation and the resultant land degradation. The increasing scarcity of firewood is compounded by Ethiopia’s high population growth rate (Ethiopian Energy Policy, 1994).
Every year, another 200,000 hectares are destroyed: the rising consumption of firewood plays a crucial part in this. As the degree of deforestation increases, so does the amount of time spent predominantly by women and children searching for firewood also increases. This energy source, which even the poorest of the poor are able to procure, is almost exhausted. Despite the scarcity of resources, firewood is burned very inefficiently in open fire places.
In seeking an efficient wood-fired cookstove for this particular project, World Vision Australia and World Vision Ethiopia approached researchers at LBNL after learning of the Berkeley-Darfur Stove being disseminated in neighboring Sudan. For this project, the Berkeley-Darfur Stove has been modified from its original form, based on feedback from users in Ethiopia, to reflect cooking conditions specific to Ethiopian culture and cuisine and is referred to as the Berkeley-Ethiopia Stove.
This project is designing and implementing a pilot project to test the financial viability and technical feasibility of large-scale dissemination of Berkeley-Ethiopia fuel-efficient stoves using carbon credits through the Clean Development Mechanism (CDM). The specific outcome of this project will be a template for large-scale CDM-compliant replication of the pilot through commercializing, disseminating, and monitoring emissions of 1,000 CDM-compliant Berkeley-Ethiopia Stoves in Ethiopia.
The nonprofit organization, Potential Energy, is laying the groundwork for the full launch of an Ethiopia Stoves Project following the completion of LBNL’s pilot project.
According to USAID‘s 2007 study, Environmental Vulnerability in Haiti: Findings and Recommendations, it is estimated that the average life span in Haiti is shortened by 6.6 years due to the impacts of indoor air pollution caused by burning biomass indoors. Acute Lower Respiratory Illness (ALRI) is the number one killer of children under five in Haiti (as it is worldwide). In addition to these health effects, use of solid biomass fuel has significant environmental consequences. Charcoal is by far the predominant fuel source used for household cooking in urban areas: in a 2003 study, 91% of total cooking fuel measured in urban households was charcoal. In rural areas wood predominates as the primary fuel for household cooking. Inefficient cooking practices, coupled with high population density and severe poverty, place an enormous burden on Haiti’s natural resources. Already one of the most deforested countries in the world, Haiti is in desperate need of low-cost technologies such as cook stoves, which will reduce household fuel consumption.
In April 2010, a Berkeley-based team visited Haiti on a fact-finding mission funded by LBNL and coordinated through Potential Energy. Team members met with potential field partners, observed cooking practices, and collected user feedback on several stove models. The team encountered a high level of interest in cookstove projects, in part due to the outpouring of humanitarian aid and increased attention to economic and social development in Haiti in the wake of the January 2010 earthquake. However, one of the key findings of the trip was that because most aid organizations are still focused on immediate relief efforts, there is room to improve the coordination of stove dissemination activities, increase information sharing between interested parties and provide an independent assessment of the efficiency and cultural appropriateness of the stoves currently being considered for distribution in Haiti.
At this stage in Haiti’s reconstruction process, the LBNL team and its partners decided they would most effectively contribute to the reduction of fuel consumption and indoor air pollution by providing an unbiased, independent assessment of different stove types. Hesitant to introduce another stove to the market before fully assessing what is currently available in Haiti, focus was placed on developing a more nuanced understanding of the different players, stove models, dissemination approaches and impact assessment strategies existing or planned.
Researchers conducted two types of tests, Water Boiling and Controlled Cooking, to compare several stoves intended for dissemination in Haiti. Water Boiling Tests (WBTs) are a laboratory test that evaluate stove performance in a controlled environment to investigate the heat transfer and combustion efficiency of the stove while boiling a pot of water. Controlled Cooking Tests (CCTs), on the other hand, measure stove performance by cooking a local meal. The LBNL team created a Haiti-specific cooking protocol for use in Controlled Cooking Tests based on observation of cooking techniques during the fact-finding trip to Haiti.