Energy planning in buildings under uncertainty in fuel costs: The case of a hotel unit in Greece G. Mavrotas * , H. Demertzis, A. Meintani, D. Diakoulaki Laboratory of Industrial and Energy Economics, Department of Chemical Engineering, National Technical University of Athens, Zografou Campus, Athens 15780, Greece Received 1 February 2002; accepted 18 May 2002 Abstract Energy planning for individual large energy consumers becomes increasingly important due to several supply options competing and/or complementing each other and the high uncertainty associated with fuel prices. Hotel units are among the largest energy consumers in the building sector, where energy planning may greatly facilitate investment decisions for efficiently meeting energy demand. The present paper pre- sentsalinearprogrammingmodel,includingbothcontinuousandintegervariables,whichrepresentenergy flowsanddiscreteenergytechnologies,respectively.Furthermore,themodelcomprisesfuzzyparametersin order to handle adequately the uncertainties regarding energy costs. The obtained fuzzy linear program- ming model is then translated into the equivalent multiple objective linear programming model, which providesasetofefficientsolutions,eachonecharacterizedbyquantificationoftheriskassociatedwiththe uncertainenergycosts.Theproposedmethodologyisillustratedwithacasestudyreferringtoalargehotel unit located nearby Athens. Ó 2002 Elsevier Science Ltd. All rights reserved. Keywords: Energy planning; Hotels; Fuzzy numbers; Multiple objective programming 1. Introduction Energy planning at the national and regional level is widely acknowledged to be an important task for securing a technically safe, economically efficient and environmentally friendly energy supply system. Linear programming (LP) is traditionally used as the basic tool for energy plan- ninginordertominimizeenergycostunderspecifictechnical,marketandpolicyconstraints(e.g. Energy Conversion and Management 44 (2003) 1303–1321 www.elsevier.com/locate/enconman * Corresponding author. Fax: +30-10-7723155. E-mail address: mavrotas@chemeng.ntua.gr (G. Mavrotas). 0196-8904/02/$ - see front matter Ó 2002 Elsevier Science Ltd. All rights reserved. PII:S0196-8904(02)00119-X