Investigation of a gas turbine CHP system under the carbon price in Australia considering natural gas and biogas fuels

This paper presents an investigation of the impacts caused by the carbon price in Australia on a gas turbine CHP system fuelled by natural gas and biogas. Three economic cases were considered and applied to a case study: no carbon price (case one) and a carbon price with no liability (case two) for natural gas and biogas, and a carbon price with liability (case three) for natural gas only as biogas is not liable under current legislation. The most economical situation occurred in case two for both systems and the least in case three for natural gas and case one for biogas. No excess electricity was produced in any case due to the low price assumed for the feed-in tariff. A sensitivity analysis was performed by altering prices ±25%. A gas turbine CHP system fuelled by natural gas is more economically attractive to install and run in terms of financial benefit under a carbon price as long as the system is not liable to pay. In order for this system to be fuelled by biogas, a significant drop in the price of the biomass fuel must occur before this type of system becomes competitive with its natural gas counterpart.