Economic Potential of Solar Thermal Power Plants With Direct Steam Generation Compared With HTF Plants

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Jan Fabian Feldhoff ◽  
Daniel Benitez ◽  
Markus Eck ◽  
Klaus-Jürgen Riffelmann
Keyword(s):  
Thermal Power ◽  
Solar Thermal ◽  
Live Steam ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Electricity Cost ◽  
Solar Thermal Power ◽  
Technical Report ◽  
Hourly Data ◽  
Direct Steam

The direct steam generation (DSG) in parabolic trough collectors is a promising option to improve the mature parabolic trough solar thermal power plant technology of the solar energy generating systems (SEGS) in California. According to previous studies [Langenkamp, 1998, “Revised LEC Projections and Discussion of Different DSG Benefits,” Technical Report No. DISS-SC-QA-02, Almeria, Spain; Price, et al., 2002, “Advances in Parabolic Trough Solar Power Technology,” ASME J. Sol. Energy Eng., 124(2), pp. 109–125; Zarza, E., 2002, “DISS Phase II Final Report,” Technical Report EU Contract No. JOR3-CT98-0277, Almeria, Spain], the cost reduction in the DSG process compared with the SEGS technology is expected to be 8–25%. All these studies were more or less preliminary since they lacked detailed information on the design of collector fields, absorber tubes required for steam temperatures higher than 400°C, and power blocks adapted to the specific needs of the direct steam generation. Power blocks and collector fields were designed for four different capacities (5 MWel, 10 MWel, 50 MWel, and 100 MWel) and different live steam parameters. The live steam temperature was varied between saturation temperature and 500°C and live steam pressures of 40 bars, 64 bars, and 100 bars were investigated. To assess the different cases, detailed yield analyses of the overall system were performed using hourly data for the direct normal irradiation and the ambient temperature for typical years. Based on these results, the levelized costs of electricity were determined for all cases and compared with a reference system using synthetic oil as heat transfer fluid. This paper focuses on two main project findings. First, the 50 MWel DSG system parameter comparisons are presented. Second, the detailed comparison between a DSG and a SEGS-like 100 MWel system is given. The main result of the investigation is that the benefit of the DSG process depends on the project site and can reach an 11% reduction in the levelized electricity cost.

Economic Potential of Solar Thermal Power Plants With Direct Steam Generation Compared to HTF Plants

2009 ◽  
Author(s):  
Jan Fabian Feldhoff ◽  
Daniel Benitez ◽  
Markus Eck ◽  
Klaus-Ju¨rgen Riffelmann
Keyword(s):  
Thermal Power ◽  
Saturation Temperature ◽  
Solar Thermal ◽  
Live Steam ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Electricity Cost ◽  
Solar Thermal Power ◽  
Hourly Data ◽  
Direct Steam

The direct steam generation (DSG) in parabolic trough collectors is a promising option to improve the mature parabolic trough solar thermal power plant technology of the Solar Energy Generating Systems (SEGS) in California. According to previous studies [1–3], the cost reduction of the DSG process compared to the SEGS technology is expected to be 8 to 25%. All these studies were more or less preliminary since they lacked detailed information on the design of collector fields, absorber tubes required for steam temperatures higher than 400°C and power blocks adapted to the specific needs of the direct steam generation. To bridge this gap, a detailed system analysis was performed within the German R&D project DIVA. Power blocks and collector fields were designed for four different capacities (5, 10, 50 and 100 MWel) and different live steam parameters. The live steam temperature was varied between saturation temperature and 500°C, and live steam pressures of 40, 64 and 100 bar were investigated. To assess the different cases, detailed yield analyses of the overall system were performed using hourly data for the direct normal irradiation and the ambient temperature for typical years. Based on these results the levelized costs of electricity were determined for all cases and compared to a reference system using synthetic oil as heat transfer fluid (HTF). This paper focuses on two main project findings. First, the 50 MWel DSG system parameter comparisons are presented. Second, the detailed comparison between a DSG and a SEGS-like 100 MWel system is given. The main result of the investigation is that the benefit of the DSG process depends on the project site and can reach an 11% reduction of the levelized electricity cost (LEC).

Detailed Modeling of Parabolic Trough Collectors for the Part Load Simulation of Solar Thermal Power Plants

2012 ◽  
Author(s):  
F. Zaversky ◽  
S. Bergmann ◽  
W. Sanz
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Power Plants ◽  
Thermal Power ◽  
Solar Thermal ◽  
Thermal Power Plants ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Solar Thermal Power ◽  
Direct Steam

Solar thermal power plants are a promising way of providing clean renewable electric energy. These plants concentrate the incoming solar direct irradiation in order to heat up a heat transfer fluid. The collected thermal energy can be stored or instantly delivered to a power block where part of the thermal energy is converted to electrical energy in a turbine with the connected generator. The parabolic trough collector plant is the today’s most developed solar thermal power plant type. There the solar irradiation is focused on receiver tubes which are concentrically placed to the focal lines of the parabolic trough collectors. A high temperature oil is pumped through these receiver tubes, which collects the heat and delivers it later on to the steam generator of the connected Rankine steam cycle. In order to improve the efficiency of these solar thermal power plants, the direct steam generation (DSG) within the parabolic trough collector receiver tubes is being investigated. Both types of parabolic trough collectors, the conventional type using oil as heat transfer fluid and the direct steam generation type, are subject of this paper. A detailed steady-state parabolic trough collector model was developed for each type, using the thermodynamic simulation software IPSEpro. The developed models consider the cosine-loss attenuation factor, the shading attenuation factor, optical losses, as well as thermal losses. Appropriate heat transfer and pressure loss correlations were implemented for both collector types. For the direct steam generation model, distinct collectors for the preheating section, the evaporation section and the superheating section were used. Furthermore, the suitable length of discretization for the modeling of one collector loop within a center-fed solar field was investigated. Calculated solar field performance data for the oil concept were compared to validated data available in open literature. Finally, a power plant simulation with each collector type, over the course of one reference day, showed the great potential of the direct steam generation, as well as the suitability of IPSEpro for running solar thermal power plant yield simulations.

The DISS Project: Direct Steam Generation in Parabolic Trough Systems. Operation and Maintenance Experience and Update on Project Status

2002 ◽  
Vol 124 (2) ◽  
pp. 126-133 ◽  
Author(s):  
Eduardo Zarza ◽  
Loreto Valenzuela ◽  
Javier Leo´n ◽  
H.-Dieter Weyers ◽  
Martin Eickhoff ◽  
...  
Keyword(s):  
Power Plants ◽  
New Technology ◽  
Thermal Power ◽  
Test Facility ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Solar Thermal Power ◽  
Operation And Maintenance ◽  
Direct Steam ◽  
New Generation

The DISS (DIrect Solar Steam) project is a complete R+TD program aimed at developing a new generation of solar thermal power plants with direct steam generation (DSG) in the absorber tubes of parabolic trough collectors. During the first phase of the project (1996-1998), a life-size test facility was implemented at the Plataforma Solar de Almerı´a (PSA) to investigate the basic DSG processes under real solar conditions and evaluate the unanswered technical questions concerning this new technology. This paper updates DISS project status and explains O&M-related experience (e.g., main problems faced and solutions applied) with the PSA DISS test facility since January 1999.

Development of a Thermal Energy Storage System for Parabolic Trough Power Plants With Direct Steam Generation

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Doerte Laing ◽  
Thomas Bauer ◽  
Dorothea Lehmann ◽  
Carsten Bahl
Keyword(s):  
Heat Transfer ◽  
Power Plants ◽  
Storage System ◽  
Thermal Power ◽  
Sensible Heat ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Two Phase ◽  
Solar Thermal Power ◽  
Direct Steam

For future parabolic trough plants direct steam generation in the absorber pipes is a promising option for reducing the costs of solar thermal power generation. These new solar thermal power plants require innovative storage concepts, where the two-phase heat transfer fluid poses a major challenge. A three-part storage system is proposed where a phase change material (PCM) storage will be deployed for the two-phase evaporation, while concrete storage will be used for storing sensible heat, i.e., for preheating of water and superheating of steam. A pinch analysis helps to recognize interface constraints imposed by the solar field and the power block and describes a way to dimension the latent and sensible components. Laboratory test results of a PCM test module with ∼140 kgNaNO3, applying the sandwich concept for enhancement of heat transfer, are presented, proving the expected capacity and power density. The concrete storage material for sensible heat was improved to allow the operation up to 500°C for direct steam generation. A storage system with a total storage capacity of ∼1 MWh is described, combining a PCM module and a concrete module, which will be tested in 2009 under real steam conditions around 100 bars.

Modelling and Design of Direct Solar Steam Generating Collector Fields

2005 ◽  
Vol 127 (3) ◽  
pp. 371-380 ◽  
Author(s):  
M. Eck ◽  
W.-D. Steinmann
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Solar Thermal ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Final Project ◽  
Direct Steam ◽  
Attractive Option ◽  
The Stability ◽  
Eu Project

The direct steam generation (DSG) is an attractive option regarding the economic improvement of parabolic trough technology for solar thermal electricity generation in the multi megawatt range. According to Price, H., Lu¨pfert, E., Kearney, D., Zarza, E., Cohen, G., Gee, R. Mahoney, R., 2002, “Advances in Parabolic Trough Solar Power Technology,” J. Sol. Energy Eng., 124 and Zarza, E., 2002, DISS Phase II-Final Project Report, EU Project No. JOR3-CT 980277 a 10% reduction of the LEC is expected compared to conventional SEGS like parabolic trough power plants. The European DISS project has proven the feasibility of the DSG process under real solar conditions at pressures up to 100 bar and temperatures up to 400°C in more than 4000 operation hours (Eck, M., Zarza, E., Eickhoff, M., Rheinla¨nder, J., Valenzuela, L., 2003, “Applied Research Concerning the Direct Steam Generation in Parabolic Troughs,” Solar Energy 74, pp. 341–351). In a next step the detailed engineering for a precommercial DSG solar thermal power plant will be performed. This detailed engineering of the collector field requires the consideration of the occurring thermohydraulic phenomena and their influence on the stability of the absorber tubes.

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