Full chain energy analysis of fuel ethanol from cane molasses in Thailand

Published Date
Applied Energy
August 2008, Vol.85(8):722–734, doi:10.1016/j.apenergy.2008.02.002

Author 

• Thu Lan T. Nguyen
• Shabbir H. Gheewala ^,
• Savitri Garivait

• The Joint Graduate School of Energy and Environment, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand

Received 24 September 2007. Revised 28 December 2007. Accepted 1 February 2008. Available online 18 March 2008. 

Abstract

An analysis of energy performance and supply potential was performed to evaluate molasses utilization for fuel ethanol in Thailand. The Thai government recently has set up a production target of 1.925 million litres a day of sugar-based ethanol. The molasses-based ethanol (MoE) system involves three main segments: sugar cane cultivation, molasses generation, and ethanol conversion. Negative net energy value found for MoE is a consequence of not utilizing system co-products (e.g. stillage and cane trash) for energy. Taking into account only fossil fuel or petroleum inputs in the production cycle, the energy analysis provides results in favour of ethanol. A positive net energy of 5.95 MJ/L which corresponds to 39% energy gain shows that MoE is efficient as far as its potential to replace fossil fuels is concerned. Another encouraging result is that each MJ of petroleum inputs can produce 6.12 MJ of ethanol fuel. Regarding supply potential, if only the surplus molasses is utilized for ethanol, a shift of 8–10% sugar cane produce to fuel ethanol from its current use in sugar industry could be a probable solution.

Keywords

Molasses-based ethanol

Life cycle assessment

Net energy value

Energy ratio

Thailand

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