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© 2016 Author(s). This paper analyses the potential to optimize high temperature fluid back-up systems for concentrating solar power (CSP) plants by investigating the cost impact of component capacity and the impact of using multiple fuels on annual generation. Until now back-up heaters have been limited to 20MWth capacity but larger units have been realised in other industries. Installing larger units yields economy-of-scale benefits through improved manufacturing, optimised transport, and minimized on-site installation work. Halving the number of back-up boilers can yield cost reduction of 23% while minimizing plant complexity and on-site construction risk. However, to achieve these benefits it is important to adapt the back-up heaters to the plant's requirements (load change, capacity, minimum load, etc.) and design for manufacture, transport and assembly. Despite the fact that biomass availability is decreasing with increasing direct normal irradiance (DNI), some biomass is available in areas suitable for CSP plants. The use of these biomass resources is beneficial to maximise annual renewable energy generation, substitute natural gas, and use locally/seasonally available biomass resources that may not be used otherwise. Even small biomass quantities of only 50,000 t/a can increase the capacity factor of a 50MWe parabolic trough plant with 7h thermal energy storage from 40 to 49%. This is a valuable increase and such a concept is suitable for new plants and retrofit applications. However, similar to the capacity optimisation of back-up heaters, various design criteria have to be considered to ensure a successful project.

This assessment aims to identify the most suitable concentrated solar power (CSP) technologies to hybridize with Rankine cycle power plants using conventional fuels, such as gas and coal, as well as non-conventional fuels, namely biomass and waste materials. The results derive from quantitative data, such as literature, industry information and own calculations, as well as qualitative data from an expert workshop. To incorporate the variety of technology criteria, quantitative and qualitative data the Analytical Hierarchy Process (AHP) is used as the multi-criteria decision making (MCDM) tool. Only CSP technologies able to directly or indirectly generate steam are compared in regards to feasibility, risk, environmental impact and Levelised Cost of Electricity (LCOE). Different sub-criteria are chosen to consider the most relevant aspects. The study focuses on the suitability of CSP technologies for hybridisation and results obtained are reality checked by comparison with plants already being built/under construction. The results of this assessment are time dependant and may change with new CSP technologies maturing and prices decreasing in the future.Key findings of this assessment show that Fresnel systems seem to be the best technology for feedwater preheating, cold reheat steam and <450 °C steam boost applications. Parabolic troughs using thermal oil rank second for all CSP integration scenarios with steam temperatures <380 °C. Generally, for steam temperatures above 450 °C the solar towers with direct steam generation score higher than solar towers using molten salt and the big dish technology. At and above 580 °C the big dish is the only alternative to directly provide high pressure steam.In addition to a general CSP technology selection for hybridisation the framework of this study could be used to identify the most suitable CSP technology for a specific CSP hybrid project but this requires detailed information for direct normal irradiance, climate conditions

Improving power plant performance, availability and operational costs is crucial to remain competitive in today's competitive energy market. The boiler is a key component to achieve these objectives, particularly so when using challenging fuels, such as municipal solid waste or exhaust gases with high dust contents. This paper describes an innovative boiler design that has been used for the first time in an Energy from Waste plant in Bamberg, Germany. The new boiler design disregards the traditional heating surface arrangement and instead uses tube bundles arranged in parallel to the gas flow, which provides several advantages, such as reduced fouling. The paper describes the Bamberg project (boiler design and project highlights) and first operational results after 30,500h of operation. Additionally, the paper investigates further options to reduce fouling through the use of dimpled tubes, especially the ip tube ® technology. The technology is presented as well as first test results of such tubes in the Energy from Waste plant Rosenheim, Germany. The paper concludes with further applications for the parallel flow boiler design, such as cement kilns, to outline future markets Copyright © 2013 by ASME.

In Australia both natural gas and an excellent solar irradiance are abundant energy sources and its combination is one option to implement concentrating solar power (CSP) systems in Australias traditionally low cost electricity market. The recently introduced carbon pricing mechanism in Australia is likely to steer investment towards combined cycle gas turbine (CCGT) plants. This will also lead to further plants being built in high solar irradiance areas where CSP could provide valuable peak capacity. Hybridisation would enable more competitive power generation than standalone CSP systems as hybrid plants share equipment, such as steam turbine and condenser, therewith lowering the specific investment. This paper investigates the novel hybridization of CCGT and solar tower systems to increase the efficiency of integrated solar combined cycle (ISCC). Currently, all ISCC plants use parabolic trough systems with thermal oil as this technology is most mature. However, increases in plant efficiency, simpler solar tower integration as well as further synergies of solar tower ISCC systems, such as joint use of tower as CCGT stack, are likely to enhance the economic viability of new ISCC plants. In addition to a technical concept description this paper outlines the ideal sites for ISCC plants in Australia and presents a 200MWe ISCC case study with 3h molten salt thermal storage for the conversion of the Port Hedland open cycle gas turbine (OCGT) facility in Western Australia into a solar tower ISCC plant.