Based on the national greenhouse gas emission reduction target for 2030 ("GHG target for 2030") and the 2nd Energy Master Plan ("2nd EMP"), several power mix configuration scenarios were tested to estimate the sensitivity of the carbon dioxide emissions and the 'overshoot ratio', which is the ratio of ecological footprint to biocapacity. It would be only possible to achieve the GHG target for 2030 if the fraction of non-emission energy be more than 70% of the total input primary energy for power generation with the current conversion efficiency (40%). Even the conversion efficiency is changed to 50%, still the carbon dioxide emissions are larger than the targeted carbon dioxide emissions from the energy sector. The overshoot ratio would still increase from 5.9 in 2009 to 7.6 in 2035 even with the successful implementation of the 2nd EMP. Thus, additional efforts to reduce the carbon dioxide emissions and the overshoot ratio from the energy sector are required beyond adjusting the supply mix configuration for power generation and the conversion efficiency. Policies and programs encouraging the changes in consumer behavior toward reduction of goods consumption and energy savings are expected to impact on reducing the carbon dioxide emissions and the overshoot ratio. (C) 2016 Elsevier Ltd. All rights reserved.