Debajit Palit* The Energy and Resources Institute, Darbari Seth Block, IHC Complex, Lodhi Road, New Delhi 110003 Abstract The residential sector accounts for 46.8% of the total energy consumption in Bhutan. Among the various end uses, cooking is the major energy consuming end use, accounting for about 66% of the residential energy share. The rural population having limited access to electricity and other modern energy sources, fuelwood is the largest single source of energy accounting for about 91% of residential energy use. TERI conducted an extensive survey in Bhutan to evaluate the performance of the cookstoves used in different regions of rural Bhutan. This paper gives detailed account of the energy consumption in the residential energy sector in Bhutan, thermal efficiency measurements of cookstoves and exposure to households’ occupants to carbon monoxide (CO) during cooking. Based on the results, strategies for reducing fuelwood consumption and improving indoor air quality has also been discussed. Keywords: Bhutan, Energy Consumption, Cookstoves, Indoor Air Pollution 1. INTRODUCTION Bhutan is a landlocked mountainous country, having an area of 38,394 km 2 located in the eastern Himalayas. The country has a population of 634,982 persons with more than 70% of the population living in rural areas [1], where most people rely heavily on fuelwood for cooking and heating. Bhutan is estimated to have one of the highest fuelwood consumption for energy in the world. A FAO (Food and Agricultural Organization) study conducted in 1991 estimates the consumption at 1.27 ton per person per year [2] while a Department of Energy, Royal Government of Bhutan supported study, conducted by TERI, estimates fuelwood consumption at 0.85 ton per person per year [3]. One of the reasons for high consumption is the predominant use of traditional stoves built of stone and mud, with a singular open fuel cum ash door and 2-3 potholes with each having three raised lumps to sit the pots. In the absence of chimney, the three lumps allow flames to encircle the pots thereby releasing the exhaust directly into its environs. A study conducted in 2001 concludes that close to 69% of the rural households use traditional stoves, 21.5% uses smokeless cookstoves and the remaining using the open three stone facilities [4]. The smokeless stove was introduced in Bhutan as early as 1985. However, its major disadvantages perceived by the users were the limiting room heating and lighting effect [5]. The same study shared that from the user’ point of view not one model of cookstove is better or worse in terms of thermal efficiency. Although the smokeless stoves can be regulated to have a better efficiency, it appeared that in practice, rural people do not regulate the airflow, thereby having a high combustion of fuelwood, thus reducing the efficiency as most of the hot flue gas escape through the chimney. ______________________________________ *Corresponding Author: Tel: +91 11 24682100/111; Email: debajitp@teri.res.in In many households, chimneys of smokeless stoves were dismantled because of perceived fire hazards and other traditional use of smoke, such as drying chili, fish, and grains, and the smokeless stoves eventually become traditional again. 1.1 Energy Consumption in Residential Sector TERI conducted an extensive survey in Bhutan to develop an Integrated Energy Management Master Plan (IEMMP) for the Royal Government of Bhutan [6]. The survey covered a total of 5396 households (about 5% of the total households in the country), spread over urban and rural areas and covering all Dzongkhags in the country, to assess the energy consumption in the residential sector (Figure 1). The survey was conducted in three phases: 1. Pre-survey testing of questionnaires; 2. Main survey covering all selected households during summer months; and 3. Repeat survey in selected households during winter months. The TERI study concluded that the total energy consumed in the residential sector in Bhutan is estimated at 191,217 TOE (ton of oil equivalent), making the residential sector largest energy- consuming sector in the country [6]. The residential sector accounts for 46.8% of the total energy consumption, the major end-uses being cooking, lighting, space heating and cooking fodder for cattle. Among the various end uses, cooking is the major energy consuming end use, accounting for about 66% of the total residential energy share (Figure 2). Energy requirement for fodder cooking also emerge as the second largest energy consuming end use after cooking, accounting for almost one-fourth of energy consumption in the residential sector. Irrespective of socioeconomic status of the mountain communities, space heating also needs a sufficient amount of fuel wood. However, in a large number of households, the same device is used for both cooking and space heating, making it difficult to apportion fuel use between the two end uses. Performance Assessment of Biomass Cookstoves in Rural Bhutan