Techno-economic assessment for compressed biogas from palm oil mill effluent for rural electrification

Abstract

As one of the world's lead exporter of palm oil, Malaysia has generated a lot of waste from the production of palm oil. One of the highest produced waste is palm oil mill effluent (POME). POME can be utilized as fermentation media, fertilizer, and in generating biogas. Biogas is a mixture of gas consisting mainly of methane and carbon dioxide (CO2). It can be used for cooking, vehicle fuel, and to generate power. Biogas generation helps cut reliance on the use of fossil fuels and has a great potential to generate power in rural areas that has no access to an electricity grid. The government has acted in solving the issue by installing solar panels to generate electricity. However, solar is an intermittent energy source. The virtual distribution of upgraded compressed biogas to generate power has attracted attention, especially for remote electrification due to the secure supply of biogas. However, this concept poses some issues concerning logistics due to the scattered spatial distribution of palm oil mills. Addressing these aspects requires techno-economic and comprehensive supply chain analyses. The main objective of this study is to design an integration of biogas compression and bottling system for rural electrification on the available biogas plant from POME. First, a preliminary study was performed to estimate the availability of excess biogas in the palm oil mill. Second was designing the integrated compressed biogas plant with and without CO2 upgrading. Next, an analysis was conducted to identify the optimal pressure range for compressed biogas. The optimal pressure selected was 150 - 250 bar. Besides that, the economic and environmental analyses for compressed biogas production with and without CO2 upgrading were executed to know which technology is profitable and eco-friendly. From the economic analysis results, it can be seen that the production of compressed biogas with upgrading has a higher profit compared to production without upgrading. Meanwhile, for environmental analysis, the compressor is the highest contributor to greenhouse gases (GHG) emissions. In addition, a case study on the application of compressed biogas was done at Rumah Dau, Sri Aman, Sarawak. This study presented the development of a framework for synthesizing biogenset for rural electrification. Biogenset is a generator that uses biogas as fuel. Currently, the rural electrification is supplied using a 129.6 kWp solar PV hybrid system model integrated with 2 sets of 58 kW diesel generators while biogenset with a capacity of 250 kW was proposed to replace the hybrid solar and diesel engine. The results of this study showed that biogenset is more economically attractive compared to the solar hybrid system. The biogenset has higher profit compared to the solar hybrid scheme which is RM 76,554 per year. However, biogenset has higher GHG emissions compared to the solar hybrid system but lower compared to diesel generator which is 44,283 kg CO2 eq. The model of biogenset shows a promising strategy to be applied for rural electrification.