As Indonesia moves toward more advanced vehicle emission standards, lower sulfur limits in fuel, and palm biodiesel expansion, it is important to understand the impact that increasing palm biodiesel blending rates is likely to have on vehicle emissions. This study builds on a 2018 ICCT paper that analyzed the effects of biodiesel blending on air pollutant emissions in Indonesia by incorporating 84 new biodiesel performance and exhaust emission studies—28 of them conducted on palm oil and nine conducted in Indonesia or Malaysia—and compiling the results into a meta-analysis. Importantly, this analysis also accounts for recent trends, including the implementation of advanced emission control technologies, common rail fuel injection systems, and low-sulfur diesel fuel (LSD). The effects of biodiesel on nitrogen oxides (NOx), hydrocarbons, carbon monoxide, and particulate matter emissions are analyzed.

Results show that blending palm biodiesel in diesel fuel increases NOx emissions, and these effects are especially pronounced with LSD and common rail injection systems. The trend, shown in the figure below, is statistically significant and suggests an increase in NOx emissions of 12%, 17%, and 41% for B30 (a 30% blend rate), B40, and B100 (pure biodiesel) in future years in Indonesia. Additionally, modern injection systems and fuels diminish the expected reductions of PM, CO, and HC from biodiesel compared to diesel fuel. Note, however, that given the large variation in the dataset, there is uncertainty as to the precise magnitude of the biodiesel NOx effect.