6-024 (O) The Joint International Conference on “Sustainable Energy and Environment (SEE)” 1-3 December 2004, Hua Hin, Thailand 739 1. INTRODUCTION Thailand’s energy supply comes mostly from consumption of fossil fuels, a large percentage of which are imported from other countries causing concern for energy security. In addition, fossil fuels combustion is associated with emissions of CO 2 , SO 2 and NO X leading to environmental impacts. The proposed solution for these problems is using renewable energy sources instead of conventional (fossil) energy sources [1, 2]. In addition, the Energy Conservation Promotion Fund committee (ENCON Fund) authorized the Energy Policy and Planning Office (EPPO) to subsidize Small Power Producers (SPP) producing biomass energy [3]. This paper is focused on rice husk power plant because rice husk is the one major energy sources from the agro-industrial sector. Rice husk is considered to be an environmentally friendly fuel because it can mitigate CO 2 , SO X and NO X emissions when compared with conventional energy [4]. However, the emissions have not been assessed in quantitative way in Thailand. To answer that, LCA has been used to evaluate the environmental profile of energy production from rice husk. 2. RICE HUSK ENERGY OVERVIEW Rice is grown in every region of Thailand. The by-product of the milling process is rice husk, which accounts for 20% by weight of the rice. A large amount of rice husk is dumped as waste that brings waste disposal problem and methane emissions. Moreover, rice husk can cause breathing problem due to its characteristics. To maximize advantage of the waste and also to reduce the problems, some of rice husk is used as additive in cement industries [5], fertilization [6] in fields and chicken incubation [7]. These ways are not enough to significantly reduce the disposal problem. The alternative way that has been proposed is to utilize rice husk for energy. Rice husk can be converted to a useful form of energy to meet the thermal and mechanical energy requirement for the mills themselves. 3. POWER PLANT BACKGROUND The Northeastern region is particularly important as one of the major rice growing belts of the country [2]. Due to the environmental and economic scenarios, the Thai government has supported renewable energy production from indigenous sources. One project that has been conducted under this support is the Roi-Et Green Project in Roi-Et province, using Corresponding author: shabbir_g@jgsee.kmutt.ac.th rice husk as feedstock. Approximately 255 tons of rice husk supplied from Sommai rice mill, 138 tons of Shi river water and 24 MWh of electricity are required for power production in one day. The maximum power production capacity is 10.2 MW and the minimum is 6.5 MW, depending on raw materials load. The surplus electricity will be sold to EGAT for the commitment under SPP scheme for 21 years. Raw water is pretreated by demineralization before feed to boiler and cooling tower. Waste water comes from boiler blow down (flash tank) and cooling tower blow down, and then sent to treatment. Waste water treatment including pH balance, coagulation and demineralization. Solid wastes are sludge from waste water treatment, bottom ash and fly ash. 4. LCA METHODOLOGY LCA methodology is divided into 4 phases: Goal definition and scoping, Inventory analysis, Impact assessment and Interpretation [8]. 4.1 Goal Definition and Scoping Goal Definition and Scoping is the first phase of LCA, which is used for defining the objectives of the study and the system boundaries for providing environmental information [8]. The goal for this study is to collect environmental data on the electricity production from rice husk at a 10 MW power plant in Thailand based on the entire life cycle. Energy and material balances will be conducted to evaluate the efficiency of power production. Data on emissions will yield the environmental impacts potentials. Since rice husk is considered as a waste of the rice production, the system boundary includes only energy generation. Transportation, construction, and emissions in water as also emissions from rice cultivation and production are not included in the boundary. Functional unit for this study is 1 MWh of electricity. All resources, materials and energy consumed and potential environmental impacts will be identified. 4.2 Inventory Analysis Inventory Analysis is the identification and quantification of energy, water and materials usage and environmental releases. The step starts from list of inventories, data collection then calculation of material and energy balances, carbon balance and, data analysis. According to the conservation law, matter and energy can not be created or destroyed [9]. Hence, material/energy inputs must be equal to material/energy outputs. The balances are Environmental Profile of Power Generation from Rice Husk in Thailand Thipwimon Chungsangunsit 1 , Shabbir H. Gheewala 1,* and Suthum Patumsawad 2 1 The Joint Graduate School of Energy and Environment , King Mongkut’s University of Technology Thonburi,, Bangkok, Thailand 2 Department of Mechanical Engineering, King Mongkut’s Institute of Technology North Bangkok, Bangkok 10800, Thailand Abstract: The use of fossil fuels causes environmental and energy security problems. Renewable energy is being looked at as an alternative for Thailand. Biomass from agriculture, especially rice husk, is a very promising renewable energy source since it is indigenous and is considered to have environmental benefits. However, the environmental profile of the electricity production from biomass must be assessed to ensure reduced environmental damage. This article considers the environmental evaluation of a 10 MW pilot plant using rice husk as feedstock. The environmental impacts from rice husk energy power plant are evaluated using the Life Cycle Assessment (LCA) methodology. Energy, material and carbon balances have been determined for tracing the system flow. Most impact potentials from rice husk energy are lesser than fossil fuels plants; except the photo-oxidant formation potential from CO. The performance of rice husk power plants can be enhanced by improving the combustion efficiency. Keywords: Fossil Fuel, Environmental Impact, Renewable Energy, Rice Husk, Life Cycle Assessment (LCA).