Parabolic Trough Concentrated Solar Power Plant Research Articles

Techno and economic assessment of dry cooling option for concentrated solar power (CSP) plant in the desert region

The cogency of dry cooled concentrated solar power (CSP) plant to assess its odds or accretion against the wet cooled plant is investigated in this work in hot and cold desert regions. Dry cooling proves to be a flipside option over the wet cooling system in locations where water resource is scarce. In the current work, the Andasol Parabolic trough CSP plant in Spain, which has 50 MWel nominal capacity with thermal energy storage (TES) hours of 7.5 at full load, is considered a reference plant. Simulation is performed for both wet and dry cooling options using Greenius software initially at the original plant location in order to validate results by considering actual plant values. Simulations were performed at Jodhpur and Leh with the help of the local metrological data. The parameters such as annual mean overall efficiency, levelized cost of electricity and water consumption with dry cooling for the reference plant at study site Jodhpur stand at 15.6%, 0.13 €/kW h LCOE, and 74,793 m3/year, respectively, whereas the same for wet cooled reference power plant yields 17%, 0.11 €/kWh LCOE (levelized cost of energy), and 5, 71, 365 m3/year at an annual energy yield of 163.24 GWhel net. The net electricity generation is high at Leh compared to Jodhpur, India. It is observed that dry cooling has given higher turbine efficiency except for the summer season due to very low ambient temperatures in Leh.

Assessment of the impact of thermal energy storage operation strategy on parabolic trough solar power plant performance

This numerical study aims at assessing the impact of the thermal energy storage (TES) operation strategy on the performance of a parabolic trough concentrated solar power plant (PT-CSP). This strategy consists of managing the TES charging process in order to minimize the plant's parasitic consumption. The study was conducted using a TRNSYS based dynamic simulation model of a 55 MWe PT-CSP plant similar to the ANDASOL plant located in the South of Spain. The simulation results were validated in comparison with the available experimental data in the literature. The results showed that the suggested operating strategy is efficient as the heat transfer fluid and the TES molten salt pumps' total parasitic consumption is reduced by 21% during a typical clear day of July. Consequently, the plant's net energy production was improved by 0.8%. The resulting improvement in the overall efficiency of the plant was found to be 2.4%.

Dynamic simulation and performance analysis of a parabolic trough concentrated solar power plant using molten salt during the start-up process

Daily start-up is a typical feature of concentrated solar power plants (CSPs) due to solar energy intermittency. Therefore, appropriate start-up operation strategies are significant for CSPs. A parabolic trough concentrated solar power plant (PTCSP) with molten salt (MS) is a potential technical route. However, little attention has been paid to the dynamic start-up performance of PTCSP using MS. To mend the research gap, the dynamic start-up simulation of PTCSP using MS is conducted. Main contributions of this study are the dynamic start-up simulation of PTCSP using MS and evaluation of two MS anti-freezing solutions. Results indicate that the outlet MS temperature of solar field transiently exceeds nominal values during start-up processes. The inlet feedwater temperature of the preheater is much lower than MS freezing temperature during start-up processes. Therefore, two anti-freezing solutions were used to avoid MS solidification. Compared with utilizing the recirculating pump, utilizing the low-load regenerative heater can enhance anti-freezing performance, which could reduce the maximum control deviation of the preheater inlet feedwater temperature by 2.0 °C and increase the average outlet MS temperature of the preheater by 2.4 °C. This study may provide guidance for the dynamic simulation and operation optimization of CSPs during start-up processes.

A critical review of the greenhouse gas emissions associated with parabolic trough concentrating solar power plants

Abstract Numerous research studies have focused on the Life Cycle Assessment (LCA) of solar energy systems, and more concretely, within the last decade, on the environmental performance of parabolic trough solar power plants. Due to ever-increasing global energy demands, the optimization of energy solutions to reduce adverse environmental impacts has been attracting research efforts. The study presented herein reports on the environmental perspective of parabolic through concentrated solar power (CSP) plants, focusing on greenhouse gas emissions. Existing studies on the environmental impacts of parabolic trough CSP plants show significant differences regarding the scope and frontiers of the LCA, database employed, raw materials, lifetime of the CSP plant, and temporal assumptions. The convergences and divergences appearing in the most relevant papers are recompiled, disaggregated by system and LCA phase, identifying the parameters with higher impacts and calculating the influence on environmental issues. The scientific literature review carried out demonstrated a knowledge gap on inventory data for parabolic trough CSP plants. This study provides a framework for the establishment of energy policies and standards, along with data for the environmental optimization of parabolic trough CSP plants.

A Through-Life Cost Analysis Model to Support Investment Decision-Making in Concentrated Solar Power Projects

This research paper aims to propose a through-life cost analysis model for estimating the profitability of renewable concentrated solar power (CSP) technologies. The financial outputs of the model include net present value (NPV) and benefit-cost ratio (BCR) of the project, internal rate of return (IRR) and discounted payback period (DPBP) of the investment, and levelized cost of energy (LCoE) from the CSP technology. The meteorological data for a specific location in the city of Tucson in Arizona is collected from a network of automated weather stations, and the NREL System Advisor Model (SAM) is applied to simulate hourly energy output of the CSP plant. An Excel spreadsheet tool is designed to calculate, in a bottom-up approach, the financial metrics required for approval of CSP projects. The model is tested on a 50 MW parabolic trough CSP plant and the results show an annual energy production of 456,351,232 kWh, NPV of over $64 million and LCoE of 0.16 $/kWh. Finally, a sensitivity analysis is performed to identify the factors which have the most significant effect on the economic performance of CSP technologies. The proposed model can provide valuable guidance to support the strategic planning and investment decision-making in CSP projects.

An Evidential Prospect Theory Framework in Hesitant Fuzzy Multiple-Criteria Decision-Making

In numerous real decision-making problems, decision-makers (DMs) encounter situations involving hesitant and probabilistic information simultaneously, and DMs show behavior characteristics of nonrational preferences when they encounter decision-making situations with uncertain information. To address such multiple-criteria decision-making (MCDM) issues with hesitant and probabilistic information and nonrational preferences, a novel method, called the evidential prospect theory framework, is developed herein based on evidence theory and prospect theory, where the associated coefficients in prospect theory are given on the basis of symmetry principles (i.e., the associated coefficients are common knowledge to DMs). Within the proposed method, belief structures derived from evidence theory apply to the experts’ uncertainty about the subjective assessment of criteria for different alternatives. Then, by combining belief structures, the weighted average method is applied to estimate the final aggregated weighting factors of different alternatives. Furthermore, considering the nonrational preferences of DMs, the expected prospect values of different alternatives are derived from the final aggregated weighting factors and prospect theory, which is applied to the ranking order of all alternatives. Finally, a case involving a parabolic trough concentrating solar power plant (PTCSPP) is shown to illustrate the application of the novel method proposed in this paper. The evidential prospect theory framework proposed in this paper is effective and practicable, and can be applied to (green) supplier evaluation.

Optimal site selection for parabolic trough concentrating solar power plant using extended PROMETHEE method: A case in China

The Parabolic Trough Concentrating Solar Power Plant (PT-CSPP) is one of the most promising technologies for electricity generation to tackle the sharp growth in energy requirements and the finite quantities of fossil fuel in the near future. Site selection remarkably decides the whole life cycle of PT-CSPP projects considering the influences on sustainable environment and society. In consideration of the information inadequacies, the interaction problem and various properties of evaluation attributes existing in decision process, this study builds an integrated framework for PT-CSPP site selection decision applying Fuzzy PROMETHEE II approach combined with a triangular intuitionistic fuzzy generalized ordered weighted averaging (TIFGOWA) operator. Firstly, the triangular intuitionistic fuzzy numbers (TIFNs) are introduced to reflect indefinite knowledge. Secondly, the TIFGOWA operator is adopted to solve the interaction problem involved in different evaluation on alternative ratings and criteria weights of decision makers. Thirdly, fuzzy PROMETHEE II method is presented to rank the alternatives by determining preference functions and setting parameters for each criterion. Finally, a case of China with sensitive analysis and comparative analysis would be performed to certificate the feasibility of the suggested framework. The acquired result illustrates the PT-CSPP alternative situated in Qinghai Golmud would be the optimal location.

Design and comparative analysis of photovoltaic and parabolic trough based CSP plants

Solar energy can be exploited by two main methods to produce electrical energy, by means of photovoltaic (PV) panels to directly convert the sunlight into electrical energy and by using thermodynamic cycle with the help of concentrated solar power (CSP) approach to convert the heat of the sun into electricity. The objective of this research is to design and evaluate the performance of these two main methods of electrical energy generation at three different sites in Saudi Arabia. The parabolic trough CSP plant uses synthetic oil as heat transfer fluid and molten salt for the thermal energy storage system. Both CSP and PV plants have been designed for the same nameplate capacity of 100 MW. The technical comparison is performed based on solar to electrical efficiency, electrical output, capacity utilization factor, and land use factor while economic comparison includes net present value (NPV), net capital cost (NCC), levelized cost of energy (LCOE), and payback period. CSP plants have better electrical output and capacity utilization factor compared to PV plants while PV plants exhibit far better economic performance. Tabuk site is proven to be the best location for both CSP and PV plants. The best case CSP plant has 33.3% more electrical energy generation compared to the best-case PV plant. The capacity utilization factor of the CSP plant is 45.4% vs. 30.2% for PV plant. The CSP plant has 4.5 times higher NCC compared to PV plant. The LCOE of CSP plant is 2.73 times higher than that of PV plant. Overall CSP technology has better technical performance while PV technology is economically more feasible than the CSP technology at the proposed locations. This comparison between the two technologies could provide very useful guidelines for policy maker to choose the appropriate technology for a project.

Life cycle analysis of external costs of a parabolic trough Concentrated Solar Power plant

Abstract A number of developing countries have undertaken measures to diversify into renewable electricity generation. Concentrated Solar Power (CSP) is one of the technologies, though despite the high capital costs have numerous technological capabilities. CSP however is a new technology in many developing countries, where the external costs have not been fully understood. Thus far, South Africa has not conducted any detailed externalities assessments for renewable electricity sources. The presented research aims to evaluate the external cost associated with a solar CSP plant using life cycle analysis. The analysis uses a parabolic trough CSP plant with 100 MW capacity located in the Northern Cape region in South Africa. The analysis evaluated external impacts and costs for climate change, human health, loss of biodiversity, local effects on crops, and damage to materials. The study found that climate change accounted for an estimated 32.2 g CO2 eq/kWh of electricity generated. A number of non-greenhouse gas impacts were also analysed of which the effect on human health was the most significant category (0.214 g/kWh). The damage cost quantified in the study for the solar CSP plant was in the range of 2.10–3.31 ZA c/kWh (1.4–2.2 €/MWh) with a central estimate of 2.83 ZA c/kWh (1.9 €/MWh). The results suggested that climate change and human health had a combined contribution of 91% to the central estimate of the external costs which was mostly attributed by the manufacturing life cycle phase. The analysis showed that manufacturing activities have a major contribution across all impact categories. A major policy understanding is that the overall damage costs can be reduced if manufacturing the main components can be localised, to reduce the emissions caused by the transport systems. This could bring added benefits for local communities and industries.

Applicability of CSP solar fields to the dry cooling of related thermodynamic cycles

Concentrating Solar Power (CSP) technologies in arid areas suffer of a too high water consumption at the condenser of their power-block. The different alternative dry cooling technologies previously proposed to overcome this weakness lead to a decrease of 3–7% in whole efficiency of the power plant and a corresponding increase of 10% in the cost of the produced electricity. The new dry cooling approach proposed in the present study is based on using the solar field (SF) as a macro heat exchanger. Nightly, the extended available surface area of the SF allows convective thermal exchange with the surrounding environment and additional radiative heat transfer with the 3K extra atmospheric space through the atmospheric window in between 8 and 14µm. The exchanged radiative heat flow density depends directly on the optical properties of the exposed materials. In the present paper, performances of conventional and innovating reflective materials are presented through the assessment of their spectral emissivity. Aluminum film (innovating material) appears to be the most efficient one with a mean spectral emissivity around 95%, while glass mirrors (conventional materials) area round 86%. Moreover, within the spectral range of the atmospheric window 8–14µm, aluminum film is more stable than the glass mirror with a respective standard deviation of 3 and 7.8 respectively. The results confirm that radiative heat transfer can contribute to the cooling needs of linear Fresnel and parabolic trough CSP plant power block at a level of 95% and 53% respectively.

An Analysis of the Effect of Molten Salt Thermal Storage on Parabolic Trough Concentrated Solar Power Plant Efficiency

In the development of renewable energy sources, there has been a trend toward increasing and stabilising the power output of Concentrated Solar Power Plants (CSPPs) during times of reduced solar resource through the use of Thermal Energy Storage Devices (TESDs). This study investigates whether the use of a molten salt TESD decreases the efficiency of a parabolic trough CSPP due to additional system energy losses despite prolonging the operational time of the CSPP. A theoretical analysis of a simplified CSPP was made to determine if a TESD would impact the efficiency of the CSPP. This was followed up by a survey of currently active parabolic trough CSPPs both with and without molten salt TESDs. The theoretical analysis illustrated that a TESD would have no effect on the efficiency of a CSPP. However, the survey revealed that the use of a TESD improved the efficiency of a CSPP. The results of the study don't support the theoretical analysis or the hypothesis suggesting that a property has been overlooked. This property is most likely to be that generators tend to operate best within a certain temperature range, and in a CSPP the optimum temperature range cannot be maintained. This results in a generator being selected capable of operating for the longest period with the lowest amount of excess solar energy. When a TESD is implemented, the excess solar energy is stored for later use, prolonging the generator's running time and increasing the useable energy. The realisation of the ability of a TESD to increase the efficiency of a CSPP as well as extending its operating time shows a promising area of development in CSPP technology and increasing its application in electricity generation.

Heat Transfer Fluid Life Time Analysis of Diphenyl Oxide/Biphenyl Grades for Concentrated Solar Power Plants

Abstract To gain a better understanding of how purity affects fluid degradation in concentrated solar power (CSP) plants, commercially available eutectic diphenyl oxide/ biphenyl heat transfer fluids were tested for their thermal stability at different temperatures and for their chlorine content. A model for thermal degradation of the eutectic diphenyl oxide/ biphenylfluids in a parabolic trough CSP plant was built based on laboratory testing results and average fluid analysis results from operating CSP plants. Fluid degradation was compared between high quality product at 99.9% purity such as DOWTHERM™ AHeat Transfer Fluid and commercially available products with purities around 99.5%. A range of 1.7-2.4 times more degradation was determined for 99.5% purity fluids compared to the 99.9% quality for the operating conditions in a CSP plant. More frequent degradation separation operations are needed for lower 99.5% purity fluids, which ultimately means extra operating cost. In addition to that, the additional new fluid refills needed over a 25 years of operation is $2/kg. DOWTHERM™ is a trademark of The Dow Chemical Company.

Economic implications of thermal energy storage for concentrated solar thermal power

Solar energy is an attractive renewable energy source because the sun's energy is plentiful and carbon-free. However, solar energy is intermittent and not suitable for base load electricity generation without an energy backup system. Concentrated solar power (CSP) is unique among other renewable energy options because it can approach base load generation with molten salt thermal energy storage (TES). This paper describes the development of an engineering economic model that directly compares the performance, cost, and profit of a 110-MW parabolic trough CSP plant operating with a TES system, natural gas-fired backup system, and no backup system. Model results are presented for 0–12 h backup capacities with and without current U.S. subsidies. TES increased the annual capacity factor from around 30% with no backup to up to 55% with 12 h of storage when the solar field area was selected to provide the lowest levelized cost of energy (LCOE). Using TES instead of a natural gas-fired heat transfer fluid heater (NG) increased total plant capital costs but decreased annual operation and maintenance costs. These three effects led to an increase in the LCOE for PT plants with TES and NG backup compared with no backup. LCOE increased with increasing backup capacity for plants with TES and NG backup. For small backup capacities (1–4 h), plants with TES had slightly lower LCOE values than plants with NG backup. For larger backup capacities (5–12 h), plants with TES had slightly higher LCOE values than plants with NG backup. At these costs, current U.S. federal tax incentives were not sufficient to make PT profitable in a market with variable electricity pricing. Current U.S. incentives combined with a fixed electricity price of $200/MWh made PT plants with larger backup capacities more profitable than PT plants with no backup or with smaller backup capacities. In the absence of incentives, a carbon price of $100–$160/tonne CO2eq would be required for these PT plants to compete with new coal-fired power plants in the U.S. If the long-term goal is to increase renewable base load electricity generation, additional incentives are needed to encourage new CSP plants to use thermal energy storage in the U.S.

The cost of integration of parabolic trough CSP plants in isolated Mediterranean power systems

In this work, a technical and economic analysis concerning the integration of parabolic trough concentrated solar power (CSP) technologies, with or without thermal storage capability, in an existing typical small isolated Mediterranean power generation system, in the absence of a feed-in tariff scheme, is carried out. In addition to the business as usual (BAU) scenario, five more scenarios are examined in the analysis in order to assess the electricity unit cost with the penetration of parabolic trough CSP plants of 50 MWe or 100 MWe, with or without thermal storage capability. Based on the input data and assumptions made, the simulations indicated that the scenario with the utilization of a single parabolic trough CSP plant (either 50 MWe or 100 MWe and with or without thermal storage capability) in combination with BAU will effect an insignificant change in the electricity unit cost of the generation system compared to the BAU scenario. In addition, a sensitivity analysis on natural gas price, showed that increasing fuel prices and the existence of thermal storage capability in the CSP plant make this scenario marginally more economically attractive compared to the BAU scenario.