Prof. Fadjar Goembira
Department of Environmental Engineering, Faculty of Engineering, Universitas Andalas
Challenges in Biodiesel Utilization to Substitute Petro-diesel
According to a report from International Energy Agency (2019) the amount of carbon dioxide (CO2) emission from fuel combustion has increased from around 15 Gigatonnes (Gt) in 1971 to almost 35 Gt in 2017. The fossil fuel in form of oil utilization contributes to around 30 to 45% of the CO2 emission since 1971. Meanwhile, Organization of Petroleum Exporting Countries (OPEC) in 2011 estimated that there will be significant increase in the use of petro-diesel as compared to the increase of gasoline consumption. In order to reduce the use of petro-diesel, Indonesian Government set some regulations that put the target of biofuel use around 13.8 million kilo liters nationally by 2025. The type of biofuel that has been introduced massively is biodiesel fuel (BDF). BDF or chemically known as fatty acid methyl esters (FAMEs) is an alternative fuel to replace the use of petro-diesel that can be produced from plant/vegetable oil, animal fats and waste cooking oil (WCO), which has some advantages. Firstly, its use will create a closed CO2 cycle because emitted CO2 from combustion process will be absorbed back by plantation. Secondly, plantation as the source of feedstock is considered as a renewable resource. Lastly, the use of BDF does not need any significant modifications to diesel engine. Nevertheless, even though in Indonesia BDF production has increased from 190,000 kilo liters in 2009 to around 8.4 million kilo liters in 2019, however, some policy improvements are needed to be considered, particularly related to the efforts in pursuing targets of sustainable development goals (SDGs). At the moment, BDF in Indonesia is produced by using single feedstock, i.e., crude palm oil (CPO). As we all know, CPO currently is also used as a food source, thus, additional utilization of CPO as a fuel feedstock will increase its price and eventually will increase both the fuel and food prices. This situation shows a conflict of achieving goal number 7 in SDGs, i.e., affordable and clean energy with goal number 2, i.e., zero hunger. There are various non-edible plant oils that can be found in Indonesia, such as from Terminelia cattapa, Mimusops elengi, Vitex pubescens, Leucaena leucocephala, and Swietenia mahagoni, which were identified by a study in Andalas University Campus. Other more popular plants are Jatropha curcas, Cerbera manghas, Calophylum inophyllum, aleurites trisperma etc. Additionally, based on study conducted in Padang Municipality, people re-use cooking oil in cooking activities, in some cases up to 8 times, which is harmful to human health and harming the achievement of goal number 3 in SDGs, i.e., good health and well being. Furthermore, based on the same study, most people, particularly households, directly discharge WCO into the sewerage system. This activity is contra-productive to the fulfillment of goal number 14 of SDGs, i.e., life below water. The use of WCO as another feedstock for BDF production will avoid the failure in achieving goal number 3 and 14 of SDGs, because it can prevent people from re-using cooking oil in cooking activities, and also avoiding people from discharging WCO into the sewer. Moreover, another issue that can arise due to BDF production in Indonesia is the lack of concern in managing crude glycerol as the main by product in BDF production. Theoretically, for every 10 kg of BDF produced, there will also 1 kg of crude glycerol (glycerol with low purity) generated. In Indonesia, it is estimated that there has been an increase of crude glycerol generation due to biodiesel production from 16.5 thousand tonnes in 2009 to around 730 thousand tonnes in 2019. The increase of crude glycerol will decrease its price, and eventually the commodity becomes waste due to its abundance availability. There are many possible use of glycerol, but with low purity, some additional costs will be necessary that will further reduce product competitiveness. Some research has been conducted to directly convert crude glycerol into triacetin that is used as a fuel additive. Based on the above explanations, BDF is an alternative to substitute the use of petro-diesel, however, policies related to BDF utilization must be developed comprehensively, to avoid some emerging issues related to the achievement of certain goals in SDGs.