Optimal Design of Biomass Combined Heat and Power System Using Fuzzy Multi-Objective Optimisation: Considering System Flexibility, Reliability, and Cost

Abstract

The increase in global energy demands has led to the need for efficient decarbonisation systems to produce renewable energy. One example of such system is the biomass combined heat and power (CHP) system. Biomass CHP systems have been gaining a lot of attention in the past few years. However, the variations of energy demand and biomass supply have created a challenge in synthesising flexible and reliable yet cost-effective biomass CHP systems. A system with high flexibility and reliability requires additional equipment that perform the same functions. The addition of equipment though, would increase the total cost of a biomass CHP system. In this respect, it is a challenge to synthesise a biomass CHP design with high flexibility, high reliability, and low cost. In this paper, a multi-objective fuzzy optimisation model was developed to synthesise the optimal design of the biomass CHP considering the system cost, flexibility, and reliability. Inspired by the reliability importance concept, this work expressed reliability linearly, unlike the complex and non-linear expressions developed in the past. Moreover, the changes of equipment performance under varying loads known as partial load performance is also considered. To demonstrate the proposed approach, a case study was conducted. The objective of the case study was to synthesise a CHP system using biomass from palm oil and wood mills as feed. Several scenarios with different power demand were solved to study the model performance. Additionally, the proposed linear model is compared with a model with non-linear expressions.