Economic impact of latent heat thermal energy storage systems within direct steam generating solar thermal power plants with parabolic troughs

One possible way to further reduce levelized costs of electricity of concentrated solar thermal energy is to directly use water/steam as the primary heat transfer fluid within a concentrated collector field. This so-called direct steam generation offers the opportunity of higher operating temperatures and better exergy efficiency. A technical challenge of the direct steam generation technology compared to oil-driven power cycles is a competitive storage technology for heat transfer fluids with a phase change. Latent heat thermal energy storages are suitable for storing heat at a constant temperature and can be used for direct steam generation power plants. The calculation of the economic impact of an economically optimized thermal energy storage system, based on a latent heat thermal energy storage system with phase change material, is the main focus of the presented work. To reach that goal, a thermal energy storage system for a direct steam generation power plant with parabolic troughs in the solar field was thermally designed to determine the boundary conditions. This paper discusses the economic impact of the designed thermal energy storage system based on the levelized costs of electricity results, provided via a wide parametric study. A state-of-the-art power cycle with a primary and a secondary heat transfer fluid and a two-tank thermal energy storage is used as a benchmark technology for electricity generation with solar thermal energy. The benchmark and direct steam generation systems are compared to each other, based respectively on their annual electricity yields and their levelized costs of electricity at two different sites. A brief comparison of a passive and an active latent heat storage system is included. Finally, specific target costs for the new direct steam generation thermal energy storage system are determined based on the results of the parametric study.

[1]  Doerte Laing,et al.  Development of high temperature phase-change-material storages , 2013 .

[2]  Jan Fabian Feldhoff,et al.  Guidelines for CSP Yield Analysis – Optical Losses of Line Focusing Systems; Definitions, Sensitivity Analysis and Modeling Approaches , 2014 .

[3]  Markus Eck,et al.  Thermal storage concept for solar thermal power plants with direct steam generation , 2014 .

[4]  Markus Eck,et al.  Techno-economic heat transfer optimization of large scale latent heat energy storage systems in solar thermal power plants , 2016 .

[5]  Doerte Laing,et al.  Experimental and numerical analyses of a phase change storage unit , 2013 .

[6]  Markus Eck,et al.  DEVELOPMENT OF RECEIVERS FOR THE DSG PROCESS , 2006 .

[7]  Ulf Herrmann,et al.  Engineering aspects of a molten salt heat transfer fluid in a trough solar field , 2004 .

[8]  Louy Qoaider,et al.  Techno-economic performance of concentrating solar power plants under the climatic conditions of the southern region of Tunisia , 2016 .

[9]  J. Pacheco,et al.  DEVELOPMENT OF A MOLTEN-SALT THERMOCLINE THERMAL STORAGE SYSTEM FOR PARABOLIC TROUGH PLANTS , 2001 .

[10]  Eduardo Zarza,et al.  Analysis of the experimental behaviour of a 100 kWth latent heat storage system for direct steam generation in solar thermal power plants , 2010 .

[11]  Alexis B. Zavoico,et al.  Solar Power Tower Design Basis Document, Revision 0 , 2001 .

[12]  Markus Eck,et al.  High Temperature PCM Storage for DSG Solar Thermal Power Plants Tested in Various Operating Modes of Water/Steam Flow , 2012 .

[13]  Michael Wittmann,et al.  Influence of Different Operation Strategies on Transient Solar Thermal Power Plant Simulation Models with Molten Salt as Heat Transfer Fluid , 2014 .

[14]  Bernhard Hoffschmidt,et al.  3.18 – Concentrating Solar Power , 2012 .

[15]  T. Bauer,et al.  Material aspects of Solar Salt for sensible heat storage , 2013 .

[16]  F. Dinter,et al.  Operability, Reliability and Economic Benefits of CSP with Thermal Energy Storage: First Year of Operation of ANDASOL 3☆ , 2014 .

[17]  G. Morin,et al.  Comparison of Linear Fresnel and Parabolic Trough Collector power plants , 2012 .

[18]  Jan Fabian Feldhoff,et al.  Comparative System Analysis of Parabolic Trough Power Plants with DSG and Oil using Integrated Thermal Energy Storage , 2011 .

[19]  Werner Platzer,et al.  High temperature latent heat storage with a screw heat exchanger: Design of prototype , 2013 .

[20]  N. Siegel,et al.  MOLTEN NITRATE SALT DEVELOPMENT FOR THERMAL ENERGY STORAGE IN PARABOLIC TROUGH SOLAR POWER SYSTEMS , 2008 .

[21]  Tobias Hirsch,et al.  A systematic comparison on power block efficiencies for CSP plants with direct steam generation , 2014 .

[22]  Maike Johnson,et al.  Detailed partial load investigation of a thermal energy storage concept for solar thermal power plants with direct steam generation , 2016 .

[23]  Jan Fabian Feldhoff,et al.  Comparative system analysis of direct steam generation and synthetic oil parabolic trough power plants with integrated thermal storage , 2012 .

[24]  W. Steinmann,et al.  Experimental demonstration of an active latent heat storage concept , 2016 .

[25]  Andreas Dengel,et al.  High Temperature Latent Heat Thermal Energy Storage Integration in a Co-gen Plant , 2015 .

[26]  Ricardo Chacartegui,et al.  Analysis of two heat storage integrations for an Organic Rankine Cycle Parabolic trough solar power plant , 2016 .

[27]  Robert Pitz-Paal,et al.  Analysis and potential of once-through steam generators in line focus systems – Final results of the DUKE project , 2016 .

[28]  Doerte Laing,et al.  Characterization of Sodium Nitrate as Phase Change Material , 2012 .

[29]  Andreas Dengel,et al.  Design of high temperature thermal energy storage for high power levels , 2017 .

[30]  Z. Khan,et al.  A review of performance enhancement of PCM based latent heat storage system within the context of materials, thermal stability and compatibility , 2016 .

[31]  Wolf-Dieter Steinmann,et al.  Latent Heat Storage for Solar Steam Systems , 2008 .

[32]  Markus Eck,et al.  Introduction of the PCM Flux Concept for Latent Heat Storage , 2014 .