Hybrid Systems Based on Solid Oxide Fuel Cells. Modelling and Design

Even though solid oxide fuel cell (SOFC) technology reached a significant development milestone around 30 years ago, no hybrid system prototypes were built before the 2000 Siemens-Westinghouse plant. Due to the enormous engineering system complexity and cost, SOFC/turbine hybrid plants only attracted substantial research interest at the end of the twentieth century when environmental concerns became very visible and demanding. Considering the widespread enthusiasm regarding research and development activities for hybrid systems on the eve of the twenty-first century, a ‘partial downsizing’ is now apparent due to several unresolved engineering and sustainability problems and the ever-present, overriding cost and reliability issues.Thus, the forecast plans for commercialization carried out during the past decade seem to have failed to deliver acceptable hybrid system performance under realistic operational conditions, due to the various technological, complexity and cost issues. Furthermore, comparing the developmental status of hybrid systems with state-of-the-art anticipated performance metrics of the past decade, several publications have now presented newly validated solutions for several of the previously outstanding applied research issues (such as cost decrease, SOFC/turbine coupling and control system development), incorporating significant promising technology improvements. Hence, it is essential to consider that concentrated funding resources are still necessary to profitably combat/resolve all of the technical issues and to reach the required high levels of reliability, high plant operative life and low-cost performance for acceptable commercial adoption on a wider scale. For such reasons, focused efforts and research interests/activities at both academic and industrial levels are absolutely essential. Even if hybrid systems will not be ready for commercialization in a few years, the extremely desirable performance and environmental aspects promised via this technology will be a central pillar for future energy generation and hydrogen economy development. Due to the promising performance attributes and the recent substantial development of hybrid system technology based on solid oxide fuel cells (SOFCs), the authors have decided to develop this book to produce an updated text targeted at both practicing engineers and academic researchers. In comparison with previously published texts, the authors pay special attention to the latest research and development activities at both the theoretical and experimental levels.Thus, following the discussions of the basic aerothermodynamics and electrochemistry of the primary components (the SOFC stack and microturbine aspects are presented in Chapters 2 and 3), including updated descriptions covering the latest technological improvements and commercialization aspects, an innovative approach is considered to further develop the SOFC/turbine coupling in an individual chapter (Chapter 4). For that reason, special attention is devoted to system constraints, problem/solution details based on the latest academic/industrial research activities, and performance aspects of currently available commercial prototypes. Furthermore, the book presents details regarding hybrid system modelling activities from different points of view including theoretical/computational (Chapter 5) and physically based approaches (Chapter 6). In comparison with previous publications on SOFC based systems, this book devotes large sections and presents detailed discussion on experimental development devices collectively referred to as emulator rigs, as these tools are widely and routinely used to develop rational and profitable configurations covering hybrid systems based on SOFC and gas turbine systems. Currently, these experimental facilities show great potential regarding applied research for such power plants, and the results generated via their use are considered absolutely essential for solving several technical hardware and optimization issues for such hybrid systems. Finally, various conflicting engineering issues and commercialization potentials to be pursued for the widespread adoption of such innovative and efficient power plants are discussed in Chapter 7, focusing special attention on future perspectives and possible solutions