Development of Renewable Energy in Indonesia: Potency of Bioethanol and Biogas from Solid Waste of Palm Oil Industry

As an effort to reduce the dependency and the massive usage of fossil fuel, which causes carbondioxide emission, new and renewable energy emerge as an alternative energy source. Among others, bioethanol and biogas are two alternatives energy sources which are potentially produced from solid waste from palm oil industry, i.e. oil palm empty fruit bunch (OPEFB). This material contains high portion of lignin which need to be removed prior to the conversion into bioethanol and biogas. This paper presents the results of pretreatment of the OPEFB for the production of bioethanol and biogas. It is shown that both bioethanol and biogas production are enhanced by pretreatment process. After being pretreated by 8% of sodium hydroxide, an increase of ethanol yield by 3.9–5.0 folds are obtained. Based on the best result of ethanol yield that could be achieved, the 5.7 million ton of OPEFB (dry base) in Indonesia can result in 725 million litres ethanol per year, which is equal to 1.53 x 1016 J/year. For biogas production, OPEFB is pretreated using 73-85% of N Methylmorpholine-N-Oxide (NMMO). The methane yield is 0.379 Nm3 CH4/kg dry OPEFB. The highest methane production gives 48% of ratio enhancement (ratio the yield of methane production between treated-OPEFB and untreated-OPEFB). Based on these results, around 2.1 billion Nm3 of methane can be produced using the data of total dry OPEFB accumulated in 2010, which corresponds to 8.37 x 1016 J/year. Some important challenges need to be faced, both in technical and non-technical aspects, before this high potency of energy source can be brought into real plant