Modelling and Optimization Of Biomass Based System In Microgrid

Abstract

The handling of biomass like MSW and rice straw becomes a challenge in the present time due to various economic and environmental challenges. Finding an economical and environmentally sustainable MSW and rice straw processing system is necessary. For hybrid power generation systems, biomass can act as a balancing system to wind and solar resources due to its different properties related to reliability. The utilization of MSW and rice straw in a microgrid system will open new doors for its sustainable processing and energy generation. This study proposes modelling and simulation of MSW and rice straw-based microgrids along with their economic and environmental evaluation. The technologies are selected after a comparative analysis of various technologies in economic and environmental terms for a particular type of biomass (MSW and rice straw). The characteristic assessment and comparative analysis of various municipal solid waste (MSW) and rice straw processing technologies are proposed to fulfill this aim. In the case of MSW, landfilling is taken as the common way to handle MSW. In contrast, the technologies such as anaerobic digestion (AD), compost, refuses derived fuel (RDF), incineration, and gasification are selected as the alternate systems to process MSW. Along with the electricity generation technologies (AD, Gasification, and incineration), other technologies such as RDF and composting are selected to compare and find the most sustainable means to process the MSW. Considering the virtual operation of the existing plants, the techno-economic and environmental parameters of all the selected technologies are assessed in the Indian scenario. For evaluation of each system, the industrial ecology-based symbiotic system approach along with Life cycle assesment (LCA) is applied to Indian MSW taking a population size of one million. All the selected technologies are evaluated in detail at each step of the whole process and compared with each other in economic and environmental terms. In a similar approach, the characteristic assessment and comparative analysis of various rice straw processing technologies are also proposed. The same methodology is applied to evaluate rice straw processing techniques using incineration, gasification, AD, fermentation, and integrated operation of fermentation and AD. Then selecting the best techniques, modelling, and simulation of MSW and rice straw-based microgrids are proposed. In case of MSW the proposed microgrid is capable of processing the urban waste of a small city of 0.1 million population and fulfilling the electricity demand of a nearby village having 225 houses. The proposed microgrid consists of MSW processing techniques: AD (processes a wet portion of MSW) and gasification (processes a dry portion of MSW) that are further integrated with solar, battery, and the main grid. After selecting the gasification technique, modelling and simulation of a small-scale rice straw-based microgrid is proposed. This microgrid is capable to process the surplus rice straw of a village having 250 houses and 900 acres of cultivated land. The system processes 1128 tonne/year of surplus rice straw and meets the load demand of the same village. The gasification technique that processes rice straw to produce electricity is further integrated with solar, battery, and the utility grid. The modelling and simulation of both the systems are done using Matlab software. The size of the microgrids is optimized using an artificial bee colony (ABC) algorithm. The effectiveness of the adopted technique is verified by comparing the results with the particle swarm optimization (PSO) algorithm. The economic evaluation of the proposed systems is done based on net present cost (NPC), annualized system cost (ASC), and the levelized cost of electricity (LCOE). The landfill avoided cost is also calculated along with the waste processing cost. The environmental impact of the proposed microgrids is also evaluated using the LCA methodology.