Reduction of CO 2 emission by improving energy use efﬁciency of greenhouse cucumber production using DEA approach Benyamin Khoshnevisan, Shahin Raﬁee * , Mahmoud Omid, Hossein Mousazadeh Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran article info Article history: Received 15 November 2012 Received in revised form 31 March 2013 Accepted 16 April 2013 Available online 21 May 2013 Keywords: Greenhouse cucumber DEA GHG emission abstract The main purpose of this study was to determine energy use efﬁciency in greenhouse cucumber pro- duction using a non-parametric production function. Energy use efﬁciency of greenhouse cucumber producers was studied and degrees of technical efﬁciency (TE), pure technical efﬁciency (PTE) and scale efﬁciency (SE) were determined using data envelopment analysis (DEA). Additionally, wasteful uses of energy inputs were assessed and energy saving from different sources was computed. Furthermore, the effect of energy optimization on CO 2 emission as one of the major greenhouse gases (GHG) was inves- tigated and total amount of CO 2 emission was calculated. Average of total input and output energies were calculated as 1667164.8 MJ ha 1 and 151846.2 MJ ha 1 . Energy use pattern indicated that natural gas and electricity were the main energy inputs. Based on the results 24.46% (407916.3 MJ ha 1 ) of overall energy resources can be saved if the performance of inefﬁcient farms is enhanced. Additionally, the total CO 2 emissionwas calculated as 45177.3 kg CO 2eq ha 1 . Finally it was concluded that, by energy optimization the total energy consumption can be reduced to the value of 1,259,248 MJ ha 1 and correspondingly the total CO 2 emission is reduced to value of 34995.9 kg CO 2eq ha 1 . Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Cucumber is one of the most popular greenhouse vegetable products in Iran. Greenhouse plant production is one of the most intensive parts of the agricultural production. It is intensive not only in the sense of yield (production) and in whole year produc- tion, but also in sense of energy consumption, investments and costs [1]. From 2002 to 2007, greenhouse areas of Iran had increased from 3380 ha to 6630 ha with an increasing rate of 96%. The shares of greenhouse crops production were as follows: vege- tables 59.3%, ﬂowers 39.81%, fruits 0.54% and mushroom 0.35% [2]. Energy is used in all facets of living and in all countries, and makes possible the existence of ecosystems, human civilizations and life itself [3]. Given the growing population’s food re- quirements, the ﬁnite supply of fossil fuels and the environmental impacts of using this non-renewable resources, the existing rela- tionship between agriculture and energy must be dramatically altered [4,5]. Sustainable agriculture production is closely con- nected with effective energy use due to ﬁnancial savings, fossil resources preservation and air pollution reduction [6]. Increasing in use of energy inputs in agriculture led to numerous environmental problems like high consumption of non-renewable energy re- sources, loss of biodiversity, pollution of the aquatic environment by the nutrients nitrogen and phosphorus as well as by pesticides [7]. Global warming is one of the most important issues in recent century. Agricultural greenhouse gas (GHG) emissions account 10e 12% of all manmade GHG emissions [8]. Efﬁciency is deﬁned as the ability to produce the outputs with a minimum resource level required [9]. Data envelopment analysis (DEA) is a well-established technique for measuring efﬁciencies of a set of comparable entities by some speciﬁc mathematical pro- gramming models. These entities, which often called decision- making units (DMUs), perform the same function by transforming multiple-inputs into multiple outputs. Given a sample of the DMUs, the purpose of the DEA is to establish the relative efﬁciency of each DMU within a sample [2]. A big advantage of DEA is that it does not need any prior assumptions on the underlying functional re- lationships between inputs and outputs [10]. However several studies have been conducted on energy con- sumption in greenhouse production [1,2,11,12], none of them investigated the amount of GHG emission. Accordingly, the objectives of this study were: (a) to determine the efﬁciency of greenhouse cucumber producers; (b) to identify target energy requirement and wasteful uses of energy and (c) to assess the effect of energy optimization on GHG emissions. * Corresponding author. Tel.: þ98 2632801011; fax: þ98 2632808138. E-mail addresses: b_khoshnevisan@ut.ac.ir (B. Khoshnevisan), shahinraﬁee@ ut.ac.ir (S. Raﬁee). Contents lists available at SciVerse ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy 0360-5442/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.energy.2013.04.021 Energy 55 (2013) 676e682