Performance of Hybrid CHP Systems in Process Industries

Abstract

Biomass combined heat and power systems are an attractive option when addressing CO2 concerns, since both growth and conversion involve recycling atmospheric carbon, resulting in no net addition of CO2 to the atmosphere. The aim of this project is to investigate the cost-effectiveness of reducing greenhouse gas emissions with a hybrid Combined Heat and Power (CHP) system compared with single fuel alternatives; i.e. a gas turbine CHP system using natural gas only and a biofuel steam turbine CHP system. The hybrid CHP system is based upon a gas turbine fired with natural gas and using biofuel in the supplementary firing facility. The performance of different types of hybrid CHP systems is studied, using different turbines types and sizes as well as biomass fuel for supplementary firing the gas turbine exhaust gas stream. Furthermore, varying the degree of supplementary firing to satisfy a fixed heat demand produces a range of different hybrid CHP systems between the single fuel technologies. To accomplish the aim of the study and using as simulation tools GateCycleTM and CycleLinkTM, two main figures of merit are investigated: the Total Annual Heating Cost and the Marginal Global CO2 Reduction Cost of such systems. The results of the study show that Hybrid CHP technology is not an attractive option for the conditions investigated. Natural Gas gas turbine CHP is the most cost effective alternative and therefore the most attractive option for industry; and biofuel steam turbine CHP is the best option for society, having the lowest marginal global CO2 reduction cost.