Investigation on Biomass Briquette as Energy Source from Waste Leaf Cerbera Manghas Willyanto Anggono 1 , Fandi D. Suprianto 2 , Sutrisno 3 , Andreas W. Kasrun 4 1,2,3,4 Mechanical Engineering Department, Petra Christian University, Surabaya, East Java, Indonesia 1,2,3,4 Centre for Sustainable Energy Studies, Petra Christian University, Surabaya,East Java, Indonesia Email: willy@petra.ac.id ABSTRACT Indonesia is a tropical country and has abundant varieties of plants but has not been utilized to the fullest. One of the plants that are often encountered in the community is Cerbera Manghas. Cerbera Manghas is known as one of the trees that have solid roots thus it is widely used for greening both on the roadside on the highway and residential areas in Surabaya. Although beneficial to be a shading tree and to reduce air pollution in urban areas, waste from the leaves of this plant becomes a serious issue for the cleanliness of the city. Organic solid waste that comes from the falling leaves has the potential to be used as a solid fuel alternative in the form of briquettes when processed appropriately. This study aims to investigate the potential of waste Cerbera Manghas leaves to be used as raw material of biomass briquettes with tapioca as a binder, as well as to evaluate the property of the resulted briquettes using ultimate analysis and proximate analysis, and also the effect of the composition of tapioca to the heating value of the biomass briquettes. Heating values of five mixtures with various tapioca compositions of 10%, 20%, 30%, 40%, and 50% were evaluated using an oxygen bomb calorimeter. The experimental results showed that the biomass briquettes made of waste Cerbera Manghas leaves can be made using tapioca as a binder. The greater the percentage of the mass of tapioca in the briquettes, the lower heating value generated. Biomass briquettes made of waste Cerbera Manghas leaves can be made into a source of sustainable energy with the optimal composition of 90% waste leaves and 10% tapioca. Keywords: Biomass, sustainable energy, briquette, Cerbera Manghas. 1. Introduction Energy crisis is the concern on the diminishing of natural resources which are used to power industrial society as a result of the increase in world’s demand. These natural resources are in limited supply. While they do occur naturally, it can take hundreds of thousands of years to recover the fuel. The energy crisis occurs because of the growth in fuel consumption rate and population factors. Besides saving this non- renewable energy sources, the search for new alternative energy is needed to fulfill the human needs such as electricity, fuel and etc. Biomass is the most common form of renewable energy, widely used in the third world but until recently, less so in the Western world. The examples of biomass fuel are such as biodiesel, biogas, agricultural waste and etc. The source of biomass can be produced from agricultural crops and residues, forestry crops and residues, sea weeds and algae, animal residues, industrial residues, municipal solid waste and sewage [1]. Beside biomass as an alternative energy, development for substitute of fossil fuel such as biomass also becomes popular nowadays. An experiment about bioenergy proves that bioenergy have a potential as alternative energy source and the utilization of biomass also increases from time to time [2-6]. Indonesia is one of developing country in the world that has many resources of energy such as oil, and coal. Indonesia becomes top coal exporter in 2014. Beside, Indonesia is also one of agrarian country which was shown by the 70% from 186 million hectares is used to agricultural sector [7]. This condition gives an opportunity to produce biomass alternative energy using agricultural waste. Due to the Indonesian government go green policies, every city in Indonesia should plant more trees to minimize global warming and counter the emission of vehicle. Trees are the main element in the city park and they are useful in improving the air quality in densely populated cities such as Surabaya as shown in Fig. 1. On the other hand, planting a large number of trees causes a lot of waste leaves as shown in Fig. 2. Government and many communities in Surabaya are facing serious issue with the solid waste leaf (Cerbera Manghas) disposal problem and considerable efforts are being made to reduce the quantities of municipal solid waste.