From Linear Fuel Switching to MultipleCooking Strategies: A Critique and Alternativeto the Energy Ladder ModelOMAR R. MASERAUniversidad Nactional Autonoma de Mexico, Morelia, MexicoBARBARA D. SAATKAMPHarvard Medical School, Boston, MA, USAandDANIEL M. KAMMEN*University of California, Berkeley, USASummary. Ð Promoting sustainable development requires evaluating the technical and policyoptions that will facilitate the adoption and use of energy ecient and less polluting cooking stovesand practices. The transition from traditional to modern fuels and devices has been explained bythe ``energy ladder'' model that suggests that with increasing auence, a progression is expectedfrom traditional biomass fuels to more advanced and less polluting fuels. In this paper we evaluatethe energy ladder model utilizing data from a four-year (1992±96) case study of a village in Mexicoand from a large-scale survey from four states of Mexico. We show that an alternate ``multiplefuel'' model of stove and fuel management based on the observed pattern of householdaccumulation of energy options, rather than the simple progression depicted in the traditionalenergy ladder scenario, more accurately depicts cooking fuel use patterns in rural households. The``multiple fuel'' model integrates four factors demonstrated to be essential in household decisionmaking under conditions of resource scarcity or uncertainty: (a) economics of fuel and stove typeand access conditions to fuels, (b) technical characteristics of cookstoves and cooking practices; (c)cultural preferences; and (d) health impacts. This model also allows better estimates of the expectedfuelwood demand and indoor air pollution in rural households. Ó 2000 Elsevier Science Ltd. Allrights reserved.Key words Ð fuels, cooking, households, rural development, energy ladder, MexicoWorld Development Vol. 28, No. 12, pp. 2083±2103, 2000Ó 2000 Elsevier Science Ltd. All rights reservedPrinted in Great Britain0305-750X/00/$ - see front matterPII: S0305-750X(00)00076-0www.elsevier.com/locate/worlddev*We would like to thank the comments, suggestionsand insights from two anonymous reviewers. We areindebted to Jaime Navia and the rest of the researchersat GIRA. Consuelo Suarez Alfaro, M. D. of the Centrode Estudios Sociales y Ecologicas, A. C. providedessential contacts within Jaracuaro and helped developthe health interviews. Guadalupe Capilla Constantinolent her technical assistance and her friendship to furtherthe project. Ongoing conversations and critical feedbackfrom Daniel Klooster, Burton Singer and Kirk R. Smithare also gratefully acknowledged. We thank ReneMartinez for his help in the formatting of text andgraphs. This work was supported by a Fulbright Garcia-Robles Fellowship to B. D. S., Summer ResearchSupport from the Woodrow Wilson School, grants fromthe Summit and Compton Foundations, and the Class of1935 Preceptorship, awarded to D. M. K. Final revisionaccepted: 16 June 2000.20831. INTRODUCTIONResearchers have often attempted to under-stand the dynamics of energy use in families ofvarying incomes by reference to the ``energyladder'' as a model for household decisions tosubstitute or to switch between available fuels(Baldwin, 1986; Smith, 1987; Hosier & Dowd,1988; Leach & Mearns, 1988, Leach, 1992). Inone of its more common interpretations, whichwe refer here as the ``traditional energy ladder,''this model proposes that, as families gainsocioeconomic status, they abandon technolo-gies that are inecient, less costly, and morepolluting, i.e. ``lower'' on the energy ladder,such as dung, fuel wood, and charcoal (Smith,1987; Barnes & Floor, 1996). This dynamic isrepresented schematically in Figure 1. Anincrease in available income allows them toleave these fuels behind, and purchase tech-nologies (stoves and fuels) ``higher'' on theladder. These ``advanced'' technologies areusually more ecient and costly, but requireless inputs of labor and fuel, and produce lesspollution per unit of fuel. Implicit in this modelis the notion that the use of each dierent fuelor stove carries with it a certain status. Theenergy ladder assumes that more expensivetechnologies are locally and internationallyperceived to signify higher status, and thatfamilies desire to move up the energy ladder notjust to achieve greater fuel eciency or lessdirect pollution exposure1, but to demonstratean increase in socioeconomic status. Even whenthis model is augmented with somewhat morecomplex dynamics of economic and socialfactors, the picture that emerges is essentiallylinear: a simple progression from traditional tomodern fuels and from traditional to moreecient, and costly stoves, as a householdincome increases (Barnes & Floor, 1996).In this paper we examine the process of fuelswitching using an alternate, ``multiple fuel'',model which requires the consideration of fourfactors essential in household decision makingunder conditions of resource scarcity oruncertainty: (a) economics of fuel and stovetype and access conditions to fuels, (b) techni-cal characteristics of cookstoves and cookingpractices; (c) cultural preferences; and (d)health impacts. Speci®cally, we use data fromthree Mexican states and one illustrative villageto show that rural households do not ``switch''fuels, but more generally follow a multiple fuelor ``fuel stacking'' strategy by which newcooking technologies and fuels are added, buteven the most traditional systems are rarelyabandoned. From this perspective, householdfuels, rather than pertaining to a ladder ofpreferences with one fuel clearly better than theothers, possess both desirable and undesirablecharacteristics, which need to be understoodFigure 1. Schematic representation of the energy ladder hypothesis, which characterizes the general movement towardsincreased stove and fuel cost associated with increasing auence. Modi®ed from (OTA, 1991).WORLD DEVELOPMENT2084within a speci®c historic and cultural context.The speci®c fuel-mix choice and the relativeconsumption of each fuel is governed by thecharacteristics of the fuels and end-use devices;speci®c aspects related to fuel availability, andthe local cultural and social context thatdetermines household preferences regardingcooking fuels and lifestyles.We argue that this change in perspectiveregarding fuel switching is essential for animproved assessment of future rural energydemand and, speci®cally, for the framing ofpolicies that will promote sustainable fuelwooduse