In this study, DEA (data envelopment analysis) was applied to analyze the energy efficiency of wheat farms in order to separate efficient and inefficient growers and to calculate the wasteful uses of energy. Additionally, the degrees of TE (technical efficiency), PTE (pure technical efficiency) and SE (scale efficiency) were determined. Furthermore, the effect of energy optimization on GHG (greenhouse gas) emission was investigated and the total amount of GHG emission of efficient farms was compared with inefficient ones. Based on the results it was revealed that 18% of producers were technically efficient and the average of TE was calculated as 0.82. Based on the BCC (Banker-Charnes-Cooper) model 154 growers (59%) were identified efficient and the mean PTE of these farmers was found to be 0.99. Also, it was concluded that 2075.8 MJ ha(-1) of energy inputs can be saved if the performance of inefficient farms rises to a high level. Additionally, it was observed that the total GHG emission from efficient and inefficient producers was 27133 and 2740.8 kg CO2eq. ha(-1), respectively. By energy optimization the total GHG emission can be reduced to the value of 2684.29 kg CO2eq. ha(-1). (C) 2013 Elsevier Ltd. All rights reserved.