| 1. |
- Guedez, Rafael, et al.
(författare)
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Enhancing the Economic Competitiveness of Concentrating Solar Power Plants through an Innovative Integrated Solar Combined-Cycle with Thermal Energy Storage
- 2014
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Ingår i: Proceedings of the ASME TurboExpo 2014. - 9780791845653
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Konferensbidrag (refereegranskat)abstract
- The present work deals with the thermoeconomic analysis of an innovative combined power cycle consisting of a molten- salt solar tower power plant with storage supported by additional heat provided from the exhaust of a topping gas- turbine unit. A detailed dynamic model has been elaborated using an in house simulation tool that simultaneously encompasses meteorological, demand and price data. A wide range of possible designs are evaluated in order to show the trade-offs between the objectives of achieving sustainable and economically competitive designs. Results show that optimal designs of the novel concept are a promising cost-effective hybrid option that can successfully fulfill both the roles of a gas peaker plant and a baseload solar power plant in a more effective manner. Moreover, designs are also compared against conventional combined cycle gas turbine power plants and it is shown that, under specific peaking operating strategies, the innovative concept can not only perform better from an environmental standpoint but also economically.
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| 2. |
- Guedez, Rafael, et al.
(författare)
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Optimization of Thermal Energy Storage Integration Strategies for Peak Power Production by Concentrating Solar Power Plants
- 2014
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Ingår i: PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE. - : Elsevier BV. ; , s. 1642-1651
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Konferensbidrag (refereegranskat)abstract
- The integration of thermal energy storage systems in concentrating solar thermal power plants allows power production to be shifted from times where there is low demand to periods where electricity prices are higher. Although increasing the total investment, thermal energy storage can therefore enhance profitability of the solar power plant. The present study presents optimum power plant configurations for a given location considering different price-based grid integration strategies. Such optimum plant configurations were determined using a thermo-economic optimization approach where the operating strategy was set such that electricity was generated once the market price exceeds a given price level, defined as the minimum price selling indicator. Plants were optimized for different indicator values to cover designs from base load and peak power production. For each of these price-operating strategies, optimum plant configurations were found by varying two solar-related design parameters, namely the solar multiple and the storage size, whilst simultaneously evaluating the economic performance of each design. Finally, an economic analysis was performed for each of the optimum power plants, assuming financial conditions throughout the lifetime of the power plant. Results show that the optimum plant configurations vary with respect to the chosen operating strategy. Optimum configurations for peak power production yielded relatively smaller storage units than that of the optimum baseload plants. Furthermore, the study demonstrates that under current cost estimations, and for the specified location, concentrating solar thermal power is not an attractive option for utility-grid investors. However, it is shown that when considering a reduction in investment costs or the possibility of having renewable electricity incentives such as the investment tax credit treasury cash grant, concentrating solar thermal power plants can become an economically viable technology.
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| 3. |
- Pihl, Erik, 1981, et al.
(författare)
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Thermo-Economic Optimization of Hybridization Options for Solar Retrofitting of Combined-Cycle Power Plants
- 2014
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Ingår i: Journal of solar energy engineering. - : ASME Press. - 0199-6231 .- 1528-8986. ; 136:2, s. 021001-
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Tidskriftsartikel (refereegranskat)abstract
- A thermo-economic optimization model of an integrated solar combined-cycle (ISCC) has been developed to evaluate the performance of an existing combined-cycle gas turbine (CCGT) plant when retrofitted with solar trough collectors. The model employs evolutionary algorithms to assess the optimal performance and cost of the power plant. To define the trade-offs required for maximizing gains and minimizing costs (and to identify ‘optimal’ hybridization schemes), two conflicting objectives were considered, namely, minimum required investment and maximum net present value (NPV). Optimiza- tion was performed for various feed-in tariff (FIT) regimes, with tariff levels that were either fixed or that varied with electricity pool prices. It was found that for the givencombined-cycle power plant design, only small annual solar shares (?1.2% annual share, 4% of installed capacity) could be achieved by retrofitting. The integrated solar combined-cycle design has optimal thermal storage capacities that are several times smaller than those of the corresponding solar-only design. Even with strong incentives to shift the load to periods in which the prices are higher, investment in storage capacity was not promoted. Nevertheless, the levelized costs of the additional solar-generated electricity are as low as 10 ce/kWh, compared to the 17–19 ce/kWh achieved for a reference, nonhybridized, “solar-only” concentrating solar power plant optimized with the same tools and cost dataset. The main reasons for the lower cost of the integrated solar combined-cycle power plant are improved solar-to-electric efficiency and the lower level of required investment in the steam cycle. The retrofitting of combined-cycle gas turbine plants to integrated solar combined-cycle plants with parabolic troughs represents a viable option to achieve relatively low-cost capacity expansion and strong knowledge building regarding concentrating solar power.
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| 4. |
- Spelling, James, 1987-, et al.
(författare)
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Advanced Hybrid Solar Tower Combined-Cycle Power Plants
- 2014
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Ingår i: Energy Procedia. - : Elsevier. - 1876-6102. ; 49, s. 1207-1217
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid solar gas-turbine technology is a promising alternative to conventional solar thermal power plants. In order to increase the economic viability of the technology, advanced power plant concepts can be envisioned, with the integration of thermal energy storage and combined-cycle power blocks. In order to pinpoint the most promising configurations, multi-objective optimization has been used to identify Pareto-optimal designs and highlight the trade-offs between minimizing investment costs and minimizing specific CO2 emissions. Advanced solar hybrid combined-cycle power plants provide a 60% reduction in electricity costs compared to parabolic trough power plants. Furthermore, a 22% reduction in costs and a 32% reduction in CO2 emissions are achieved relative to a combination of parabolic trough and combined-cycle power plants.
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| 5. |
- Topel, Monika, et al.
(författare)
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Geometric Modularity in the Thermal Modeling of Solar Steam Turbines
- 2014
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Ingår i: Proceedings of the SolarPACES 2013 International Conference. - : Elsevier. ; , s. 1737-1746
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Konferensbidrag (refereegranskat)abstract
- To optimize the start-up schedules of steam turbines operating in concentrating solar power plants, accurate predictions of the temperatures within the turbine are required. In previous work by the authors, thermal models of steam turbines have been developed and validated for parabolic trough solar power plant applications. Building on these results, there is an interest to increase the adaptability of the models with respect to different turbine geometries due to the growing trend of having larger steam turbines in parabolic trough and solar tower power plants. In this work, a modular geometric approach has been developed and compared against both the previous modeling approach and 96h of measured data from an operational parabolic trough power plant. Results show a large degree of agreement with respect to the measured data in spite of the different detail levels. The new model allows for simple and fast prediction of the thermal behavior of different steam turbine sizes and geometries, which is expected to be of significant importance for future concentrating solar power plants.
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