Studies on the total cost of ownership (TCO) of electric vehicles (EVs) have become a crucial topic in academic research. As EVs have gained prominence globally, the volume of research on this subject has increased. However, previous review studies have not focused on examining trends in research that estimates the TCO for all types and technologies of EVs. Thus, our study aims to fill this gap by reviewing global trends and results of TCO studies on EVs. Our review employs the method of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to systematically collect and analyse 185 articles from 2011 to 2024. The contributions of our review are fourfold. Firstly, we construct a thematic research map to understand which topics are densely connected, thereby highlighting the core themes and focal points of the research field. As a result, future research should focus on reducing the TCO to accelerate EV adoption. Secondly, we show that the most extensively analysed vehicle technologies are battery electric vehicles (BEVs), while passenger cars are the most studied vehicle type. Thirdly, we differentiate the objectives of the TCO studies, identifying motivation gaps among them. We found that the primary objectives of the reviewed studies are TCO comparisons, followed by battery size and powertrain designs, policy scenario analysis, and TCO model developments. Lastly, we provide the range of TCO estimates for different types and technologies of vehicles. The average TCO for BEVs is found to be higher than that for internal combustion engine vehicles (ICEVs) across passenger cars, buses, trucks, and cargo vans. Electric motorcycles, however, buck this trend, with their average TCO being slightly lower than that of conventional motorcycles. Based on the review results, we propose several recommendations for policy implications and future studies.

Burdened by oil imports and subsidies for more than 5000 diesel power plants, Indonesia aims to use crude palm oil (CPO) as fuel in the power plants. Previous studies only focused on the technical feasibility of using CPO. Therefore, this study aimed to enrich the existing literature by analyzing the technical feasibility of using CPO, degummed CPO, and bleached palm oil (BPO) fuels on endurance test for 500 operational hours with a 20 kW diesel engine capacity for each type of fuels. Our analysis included component rating and the measurement of specific fuel consumption, emissions, oil dilution, and deposit materials. The assessment concluded that diesel engines using CPO, BPO, and degummed CPO increased specific fuel consumption, deposit formation, and emissions of carbon monoxide and carbon dioxide compared to engines using a 30% FAME blend in HSD or Biodiesel 30. This implies that CPO, BPO, and degummed CPO could be used in diesel engines, though fuel consumption and maintenance costs tend to increase. Based on the test results, we provided an efficient CPO supply chain from CPO mills to diesel power plants.