Background

Since the world oil crisis in the 1970s, researchers and policy makers have started under-standing and investigation on energy savings and management in the energy systems, especially power generation, industry, and transport sectors. In addition, the climate change problem has provided greater motivation to improve scientific discourse. Hence, not only investigation of greenhouse gas (GHG) mitigation potential but also study of mitigation schemes is an important issue, which has been extensively discussed in the field of energy planning and environmental management. The United Nations Framework Convention on Climate Change (UNFCCC), which was established in 1992, is an international environmental treaty to set binding obli-gations on industrialized countries to reduce GHG emissions as well as to achieve the stabilization of GHG concentration in the atmosphere (UNFCCC 2005). The Kyoto Protocol (KP) has been adopted to reduce both direct and indirect GHG emissions (UNFCCC 2008a). The GHG data reported by UNFCCC contain estimates for the direct greenhouse gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), perfluorocarbons (PFCs), hydrofluorocarbons (HFCs), and sulphur hexafluorid