From Traditional to Modern Stoves: A Chronology of Development


By Doug Barnes

India Traditional Stove: Credit C. Carnemark

Recently I participated in a very interesting workshop at Yale University. The workshop was called The Adoption Gap: Design, Development and Diffusion of Household Energy Technologies. The focus of the conference was to examine why improved biomass cooking stoves have not achieved widespread adoption even after over 25 years of promotion. Many of the presentations were very innovative. Included among the speakers was Rema Hanna, who is the author of the controversial study Up in Smoke. She talked about her well designed stove impact assessment. Unfortunately, the stove being evaluated was from India's legacy mud stove program, some of which are still being promoted. Hanna made the valid point that many current programs are still supporting such stoves. While this is true, today there are many  better designed stoves compared to those from the 1990s (see commentary on the paper). Unfortunately, public monitoring and evaluation studies of these new stoves are still fairly sparse. The presentations from the conference are not yet available on line, but I will update this blog once they become available.

Fortunately or unfortunately, I am one of a small number of people that have been involved in improved stove development for almost its entire history. I say fortunately because it has been a very interesting to observe the evolution of the programs over the years. I say unfortunately, because even today with the many innovations taking place, most poor households in developing countries still use open fires or primitive stoves for cooking.  Also, in many countries well meaning non-governmental organizations are still promoting the stoves designed in the 1990s.

I prepared a presentation for the conferences with the title, Improved Stoves:  What Have We Learned, How Do We Move Forward? The ideas for this presentation were taken from my recent book Cleaner Hearths, Better Homes: New Stoves for India and the Developing World. For those interested, a free digital copy of the book is available, or for those more interested in print, copies can be purchased online. The book describes the positive and negative aspects of India's legacy improved stove program that was abandoned in 2002. This legacy program now is universally criticized, but most people really don't understand the pros and cons of the old program. Some aspects of the legacy stove program were quite innovative, including working with NGOs, including women's groups, assigning technical agencies to evaluate design issues, and developing commercialization strategies. Many of these innovations are relevant for the promotion and sale of improved stoves today. 

As part of my presentation, I had one slide on the development of stove programs. For those just now becoming interested in the new stoves, this slide provides a historical overview of the 25 year history of improved stoves.  The text below the break is from a glossy insert in the center of Cleaner Hearths: Better Homes that was published in 2012. The rest of the book is based on empirical findings from short questionnaires and focus discussion groups carried out at the very end of India's program. The book takes a more objective approach identifying both what went wrong and also positive contributions of the program for people in India. Anyway, continue after the break to read my short history of improved stoves.

A Short History of Improved Stoves

Stoves have existed since the beginning of human history.  They have come in various sizes and styles, having been adapted to myriad cultures and food preparation methods.  As society has progressed, more sophisticated stove models have been developed.  Today’s modern kitchen reflects the many types of standardized and specialized cooking devices available, from coffee and tea pots to toasters and gas cooktops. 

In developing countries, the pattern of stoves development has ranged from traditional stoves to gas or LPG.  Over the last 30 years, various programs have promoted improved stoves as a bridge between traditional and modern ones.  The development of better stoves has witnessed several overlapping stages, which are chronicled below.

Traditional Stoves

Traditional stoves have been around for thousands of years.  Users often make the stoves, customizing them to preferred cooking styles.  In South Asia, traditional stoves are commonly made of mud, but many households use three-stone, open-fire stoves.  It is common practice in South Asia to use straw, leaves, and dung as cooking fuel.  The outdoor stove at left is being fed small twigs.  Such fuels require constant attention.

Unless the kitchen is well-ventilated or the stove is located outdoors, cooks are exposed to massive amounts of smoke emissions.  Even outdoor stoves may expose cooks to high levels of pollution.  Stove efficiency varies widely, depending on use, ranging from 10 to 20 percent.  The indoor stove at the beginning of the blog uses small blocks of wood.  The black substance visible on the back wall is tar, the product of incomplete combustion.  Carbon also covers pots and pans, making them difficult to clean. 

First Generation: Custom Built

At the outset, India’s National Program on Improved Chulhas focused on producing and disseminating stoves that the poorest households could afford.  With the exception of the chimney, these first-generation stoves were made of mud and clay, as illustrated by the Parvati stove .  Indentations in the pot opening helped to channel heat around the pan and prevent smoke from entering the kitchen.  From 1980 until about 2002, hundreds of such models were developed.  As one might imagine, with repeated heating and cooling, these stoves easily cracked and degraded.  The estimated two-year life span proved too optimistic; in practice, most stoves failed within a year. 

Rare Photo of Original Lorena Stove by M. Tay.

The Lorena stove, whose name is derived from mud (lodo) and sand (arena)—the primary materials used to make the stove—was originally developed in Guatemala.  This picture, taken in the early 1980s, depicts one of the myriad models developed throughout that decade.  Popularity among Latin America’s nongovernmental organizations, governments, and donor agencies increased.  But use of varying sizes and low-quality construction materials reduced reliability, leading to user dissatisfaction.  Today the Lorena stove is only rarely produced in Latin America. 

Second Generation: Manufactured Components

In the 1990s and early 2000s, the trend to make stoves of more durable materials also made them more expensive.  In India, the Laxmi, like the first-generation Parvati, was originally made of mud.  But in the last years of the National Program, many stoves were constructed of cement or a mixture of clay and cement, which increased the cost.  With the exception of the stove pipe, these models were made from prefabricated molds.  But the efficacy of this approach was never proven because, only a few years after adopting it, stove dissemination under the National Program ended. 

Plancha Stove: Credit Fundacion Solar

In Latin America, the Plancha—so-named because of its prominent metal griddle (plancha)—was disseminated under Guatemala’s social fund program.  A more expensive, durable stove lasting 10 or more years, the Plancha has a metal top used for roasting corn and preparing tortillas and other staple foods, a shelf for feeding wood, space on top for placing cooking utensils and equipment, and a chimney for venting smoke.  For local communities, who had other development options under the social fund program, the Plancha was a popular choice.  If a community decided on the stove option, then virtually every household  received a Plancha in return for contributions of labor and local materials.  The combination of having a durable stove along with many convenient features led to a high degree of popularity and continued stove use.

Third Generation: Manufactured Stoves

Justa Ecostove in Honduras: Credit E. Derby

Today’s third-generation stoves aim to improve quality and lower costs by manufacturing stoves locally and internationally.  Thanks to major appliance manufacturers, nongovernmental organizations, and foundations, a wider variety of manufactured stoves has entered the marketplace in developing countries.  In Central America, a rocket powered stove Justa stove was first developed by a local NGO named PROLENA/Honduras using masonry materials.  The original stove was named for the community leader Doña Justa Nuñez who really liked the idea of promoting better stoves for the women in her church group.  Later the masonry which requires significant periods of time for proper drying was replaced with a metal frame based on the experience of the Ecostove in Nicaragua.  This permitted the Justa stove to be produced with a higher level of quality control and in a shorter period of time.   This was accomplished with support from groups such as Trees, Water, and People, Rotary International, and the Aprovecho Research Center. The metal Justa Stove is now mass produced by the Honduran Association for Development (AHDESA) which permits many more low-income families to benefit from indoor smoke reduction made possible by chimney and the better combustion efficiency of the stove.

Another approach to manufacturing better stoves has been taken by companies such as Envirofit, International that make a wide variety of products for worldwide market.   Envirofit International produces a line of cookstoves including portable wood, charcoal, and built-in designs. Their development was a result of a partnership with the Shell Foundation Breathing Spaces program, and requires all of their stoves to meet the industries’ most rigorous performance and emissions standards – largely possible through their patent-pending design and materials advances.  The company mission is to achieve high sales volume and economies of scale by selling high-quality, low cost and durable stoves at a global level. Centralized production has allowed them to meet large initial demand in India and Africa, and they are pursuing localized assembly and production in key markets.  The available 5-year warranty and approximately 30% efficiency levels make them attractive to carbon programs.  The pricing for the stoves ranges from $15 to $30.

The Ecostove which is based on the rocket stove design was developed by a Nicaraguan nongovernmental organization called Proleña under the Pro-Tortilla program.  The stove’s innovative combustion chamber design and chimney account for the removal of most smoke from the kitchen.  More expensive than first- or second-generation stoves, the Ecostove sells for US$40–60.  But because the stove lasts 5 or more years, the annual cost is comparable to that of a traditional mud stove.   The challenge in these programs is to make the stove affordable through innovative financing to keep the monthly costs low.

Modern Fuels and Gasifier Stoves

India LPG Stove: Credit D. Barnes

At the top of the energy ladder for cooking is LPG.  Historically, LPG use in India has been restricted to urban areas and high-income households.  But because of its convenience and low emissions, LPG is gradually spreading to poorer areas, having reached some 20 percent of rural households.  To preserve their low cash income, less wealthy households use LPG sparingly, in combination with biomass fuels.  The LPG stove tank is connected by a tube to the stove-top burners.  Depending on the cooking task, the range of stove efficiency is 55–70 percent; even cooking pots and pans remain clean on the bottom.  For low-income households, the main barriers to LPG use are the connection charges: purchase of stove, tank rental, and required purchase of large quantities of LPG (typically sold in 12–16 kg cylinders). 

Widespread adoption of this convenient fuel illustrates that cooks can adapt myriad cooking styles to a fairly universal stove if it is easy to use, can start and stop quickly, and is clean burning.  This lesson reinforces the goal of developing woodstoves that are flexible in adapting to many cooking styles.

In Yunnan Province, China, The Nature Conservancy is partnering with Chinese government agencies and the U.S. Environmental Protection Agency to reduce fuelwood demand and address threats to biodiversity and human health by introducing alternative energy technologies in rural homes and schools.  The biofuel stove in Xidang, a village along the Mekong River Valley, is not a common stove in China, but illustrates the wide variety of options for clean cooking in the developing world.

Conclusion

Worldwide the various programs to promote new stoves for better energy efficiency and reduced air pollution have shared many features even though there has been little contact between the programs.  The earliest ones featured custom-built stoves focused mainly on improving energy efficiency for the poorest households.  Many years later, an increasing trend toward manufacturing components or entire stoves emphasized ways in which to reduce indoor air pollution.  An overriding concern has been finding affordable ways to promote these innovative stoves to the many people around the world who rely on biomass to meet most or all of their cooking needs.

Many of the challenges in promoting better stoves remain today.  Simply stated, it is not easy to design inexpensive stoves that are both affordable by the poor and far superior to their centuries-old cooking devices.  Past attempts to resolve these issues no doubt hold the key to developing ways to bridge the vast differences between those using traditional forms of cooking energy and those taking advantage of more modern cooking fuels and appliances.  The current trend is toward a greater role for the manufacturing of durable, efficient, and less polluting stoves, and there are many new designs around the world.  But the continuing challenge is finding ways to make these new stoves more affordable and suited to the needs of the world’s populations who still depend on centuries-old cooking practices.