Muhaimin Iqbal
Author

Unitizing Bio-based Energy

Advanced Renewable

Mon , 08 Jul 2024 21:36 WIB

In contrast to fossil energy such as oil, natural gas and coal, which are relatively homogeneous in very large quantities, making it easier to build efficient large-scale processing units, bio-based energy sources tend to be spread geographically and in terms of type.

Geographical distribution can be approached with Decentralized Energy Resources (DER), namely creating small processing units and each one close to the location of the energy source. What about distribution in terms of type?

Bio-based energy sources are abundant but the types are very diverse, they can be dry solid waste, wet solid waste, liquid waste, livestock waste, fish waste, energy crops such as elephant grass or napier grass, aqua culture such as micro and macro algae, energy plants such as calliandra, and many others. How to unite such diverse energy sources into one uniform product so that it can be industrialized?

All types of biomass energy raw materials can always be processed in one of two ways, namely through a biodigester and through gasification. Biodigesters, which are more common, are used to process wet biomass or liquids such as livestock manure, liquid waste from the food processing industry, etc. Meanwhile, gasification can be carried out using air/O2 and CO2 gasification agents for dry solid waste such as wood, charcoal, etc., or using steam for wet biomass such as algae, microalgae and napier gas which is processed fresh.

The result of the biodigester will be biogas which generally consists of biomethane (CH4) and CO2 in high concentrations (40-60%), this high CO2 will be an obstacle if it has to be disposed of, apart from being an expensive process it also throws away substances that can still be processed. So the biogas as a whole (CH4 and CO2) can be reformed to become CO and H2 which is called syngas.

Because gasification products, whether using air/O2, CO2 or steam, will all be in the form of syngas, it is at this syngas level that bio-based energy can be combined from any source. The relatively homogeneous syngas content, consisting of CO, H2, CO2 and CH4, can then be further upgraded to become syngas rich in H2 which can be processed into green fuel in the form of green diesel, biogasoline, bioLPG etc.

Green electricity can also be generated in two ways, namely using green diesel to fuel generator sets in general, or more efficiently using waste heat to become electricity through the Organic Rankine System (ORISYS). So the bio-based source can be anything, but when it comes to fuel or electricity, it can all be the same.