Solar Tower-biomass Hybrid Plants – Maximizing Plant Performance

Abstract Concentrating solar power (CSP)-biomass hybrids plants are becoming increasingly interesting as a low cost option to provide dispatchable renewable energy since the first reference plant commenced operation late 2012, 22.5MWe Termosolar Borges in Spain. The development of such project is a complex task with not only one but two energy sources required to make the project successful. The availability of several studies but only one reference plant worldwide is proof of that. This paper investigates the hybridisation of a biomass power plant with a molten salt solar tower system. The benefit of this combination is a high cycle efficiency as both the steam generators can provide steam at 525 °C and 120 bar to the steam turbine. A case study approach is used to provide technical, economic and environmental benefits of a 30MWe CSP-biomass plant with 3 h thermal storage in Griffith, New South Wales. At this site such a plant could provide annually 160,300MWh of electricity with an annual average electricity price of AU$155/MWh. Compared to a standalone CSP plant with 15 h of thermal storage the hybrid plant investment is 43% lower, providing a possibility to fast-track CSP implementation in countries where CSP is struggling to enter the market due to low wholesale electricity prices, such as Australia.