Prof. M.Shahidul Islam,
Universiti Malaysia Sarawak.
Department of Mechanical and Manufacturing Engineering
Research area: Operations Research in Engineering for Achieving Economic and Environmental Sustainability
Title: Waste Biomass the Potential Renewable Energy Source: A 2021 Update
Traditionally waste biomass has been used in various economic activities. A major percentage of waste biomass have been also used as a boiler feedstock for the producing of steam, which has identified as a poor thermal efficient process and a threat to the environment. This study has conducted to reveal advanced technologies employed for the converting of waste biomass into energy at a higher thermal efficiency. The data disclosed in this paper have collected from the published papers and reports mostly published in the years from 2000 to 2021.Biomass is an efficient convert of solar energy to renewable energy. The most available waste biomass are municipal solid waste, sugarcane bagasse and trash, palm waste biomass and woody biomass. The energy potential of this biomass depends on moisture content. The average calorific value (LHV) of these waste biomasses are about 8 MJ/Kg at 50% moisture and 15 MJ/Kg at 30% moisture. Gasification technology has been used to produce syngas from waste biomass. Pyrolysis has been traditionally used to produce both liquid (bio-oil at temperature about 300oC) and syngas (methane and hydrogen at higher temperature ≥700oC). The syngas (gaseous product) produces in pyrolysis and gasification contain (volumetric percentage) 39.71% CO, 16.48% CO2, 36.26% H2, and 7.55% CH4. Finally, through turbine electricity is produced from syngas. Combined Heat and Power (CHP) cycle has been also used together with both gasification and pyrolysis for the increasing of thermal efficiency ((≥90%) in producing energy from waste biomass, which is also contribute to reduce carbon emission rate ( CO2eq/kWh). By the aid of CHP, the energy recovery rate from waste biomass is about 0.44 MWh/ton. The case studies published by international renewable energy agency (IRENA) demonstrated, waste biomass based renewable energy project is environmentally and economically feasible. If fossil fuel replace by waste biomass for energy production, it would contribute to reduce carbon emission at the rate of 621 KgCO2eq/MWh. In the aspect of economic feasibility, the Internal Rate of Return (IRR) on investment for the biomass-based energy project is found to be 10% with a positive Net Present Value (NPV). The information documented in this paper would be useful as a guideline for policy makers, government agencies and energy industries for implementing small and economic scale renewable energy projects. Based on the findings stated, this study concludes; waste biomass is a feasible substitute for fossil fuel. Waste Biomass conversion to energy would also contribute to reducing carbon emission (CO2eq); and as well as can be a source of renewable fuel for the achieving of SDG-7 (clean energy) and SDG-13(climate actions).