This paper presents the potential of renewable power generation in Thailand for CO2 mitigation under the framework of Nationally Appropriate Mitigation Actions (NAMAs). This study employed AIM/Enduse model of the National Institute for Environmental Studies (NIES) Japan for analyses of CO2 mitigation in the power sector. Results show that in the business-as-usual scenario CO2 emissions in the power sector will be 141.51 kt-CO 2 in 2020. When the renewable energy sources under Thailand's renewable energy development plan and low-carbon options were pushed into NAMAs, CO2 emissions in 2020 will be decreased by 27.41 kt-CO2, and reduction will be 17.20 kt-CO2 with renewable power generation by adders. When both policy measures of adders and low-carbon options are considered, CO2 emissions will decrease to 98.17 kt-CO2. Thus, this CO2 mitigation of 30.6% in 2020 in power generation needs strong efforts from Thai government and international supports to achieve climate change mitigation under NAMAs mechanism. © 2011 IEEE.