Abstract. Indonesia has released two different Greenhouse Gas (GHG) emissions reduction targets. The first target, released in 2009, is reduction GHG emissions 26% from Business-as-Usual (BAU) level using own budget and up 41% if supported international aids by 2020. The second target is reduction 29% and 41% from BAU by 2030 using own budget and with international support, respectively. In this paper, the BAU emissions and emissions reduction target of these two targets are elaborated. In addition, the characteristics of emissions from transportation sector are discussed. One of the potential mitigation actions is switching fuel in transportation sector. The results the most promising mitigation action in the transportation is switching oil fuel with biofuel. The Government of Indonesia (GoI) focuses on using biodiesel and bioethanol to run internal combustion engine in transportation sector and biogas is aimed to fuel power plant unit. However, there is very limited of success stories on using biogas in the power plant. The barriers and challenges will be discussed here. It is suggested to run internal combustion engine with biogas.