Concentrated Solar Power Technology Research Articles

LCOE analysis of tower CSP plants using different molten salts for TES in China

In recent years, Chinese government is vigorously developing concentrating solar power (CSP) technology. It is one of the most promising renewable-based electricity generation technologies to deal with the increasing demand of electricity consumption and environmental sustainability. For the commercialization of CSP technology, low cost is a precondition. However, studies of electricity generation cost analysis for CSP systems, particularly for the tower systems, in China are quite limited. This paper conducts an economic analysis by applying the levelized cost of electricity (LCOE) model for 100 MW tower CSP plants in various locations in China with four different molten salts for thermal energy storage (TES). The results show that it’s inappropriate to build a CSP plant nearby Shenzhen and Shanghai since their LCOEs are higher than 6 RMB kWh−1. There is an optimal capacity of TES resulting in the lowest LCOE for a certain tower CSP plant. And the solar salt has lower LCOE than the other three new molten salts. In order to calculate the time when the grid parity will be reached, four scenarios for CSP development roadmap proposed by International Energy Agency (IEA) are considered in this study. It can be found that the grid parity of tower CSP electricity would be reached in the years of 2038-2041 in the case of no future penalties for the CO2 emissions, and bring forward about 7-14 years when considering the penalties for the CO2 emissions. This research can provide support for government to formulate incentive policies for the CSP industry.

Thermodynamic Performance Evaluation of a Solar Parabolic Dish Assisted Multigeneration System

The concentration ratio of the parabolic dish solar collector (PDSC) is considered to be one of the highest among the concentrated solar power technologies (CSPs); therefore, such system is capable of generating more heat rate. The present paper focuses on the integration of the PDSC with the combined cycle (gas cycle as the toping cycle and steam cycle as the bottoming cycle) along with the utilization of waste heat from the power cycle to drive the single effect lithium bromide/water absorption cycle. Molten salt is used as a heat transfer fluid in the solar collector. The engineering equation solver (EES) is employed for the mathematical modeling and simulation of the solar integrated system. The various operating parameters (beam radiation, inlet and ambient temperatures of heat transfer fluid, mass flow rate of heat transfer fluid, evaporator temperature, and generator temperature) are varied to analyze their influence on the performance parameters (power output, overall energetic and exergetic efficiencies, outlet temperature of the receiver, and as coefficient of performance (COP) and exergy efficiencies) of the integrated system. The results show that the overall energy and exergy efficiencies are observed to be 39.9% and 42.95% at ambient temperature of 27 °C and solar irradiance of 1000 W/m2. The outlet temperature of the receiver is noticed to decrease from 1008 K to 528 K for an increase in the mass flow rate from 0.01 to 0.05 kg/s. The efficiency rate of the power plant is 38%, whereas COP of single effect absorption system is 0.84, and it will decrease from 0.87 to 0.79. However, the evaporator load is decreased to approximately 9.7% by increasing the generator temperature from 47 °C to 107 °C.

Techno-Economic and Life Cycle Analysis of Energy Generation Using Concentrated Solar Power (CSP) Technology in Sokoto State. Nigeria

: In this work a predictive performance simulation of Solar Tower, Linear Fresnel and Parabolic Trough Concentrating Solar Power (CSP) plants was undertaken for Sokoto State in Northwestern Nigeria. The State was selected based on its high Direct Normal Irradiation (DNI) values and long hours of sunshine per day relative to other places in Nigeria. The simulation was done using System Advisor Model (SAM) Software. In the study, 50 MW, 75 MW and 100 MW for each of the three CSP technologies were considered and their Techno-economic and Life Cycle analyses were carried out. The results showed that Solar Tower plant is more favored to be adopted for use in the studied site because it has the highest annual electrical energy generation, higher capacity factor and lowest Levelised cost of Electricity. The Net Present Values of the CSP plants at the site are (with the exception of the 50 MW Linear Fresnel CSP using hybrid cooling) positive implying that the project is economically viable. The study also showed that at solar multiple of 2, the Levelised costs of Electricity for both Solar Towers and Parabolic Troughs were the lowest, irrespective of the cooling system (wet or dry cooling). Solar multiple has no effect on the water usage irrespective of the CSP plant. Dry cooling system reduces the water usage by 86% and 95% for Solar Tower and Parabolic Trough plants, respectively. Dry cooling system reduces the annual electrical energy generation in the range of 7.3 to 7.5 percent for Solar Tower plant and 8 to 9 percent for Parabolic Trough plant. The largest environmental impact was human toxicity at 25,400 g 1,4-DB eq. and the least is marine ecotoxicity at 1.33 × 10-4 g 1,4-DB eq.Keywords: Annual Generation; Debt Fraction; Human toxicity; Freshwater Eutrophication

LCOE Analysis of Tower Concentrating Solar Power Plants Using Different Molten-Salts for Thermal Energy Storage in China

In recent years, the Chinese government has vigorously promoted the development of concentrating solar power (CSP) technology. For the commercialization of CSP technology, economically competitive costs of electricity generation is one of the major obstacles. However, studies of electricity generation cost analysis for CSP systems in China, particularly for the tower systems, are quite limited. This paper conducts an economic analysis by applying a levelized cost of electricity (LCOE) model for 100 MW tower CSP plants in five locations in China with four different molten-salts for thermal energy storage (TES). The results show that it is inappropriate to build a tower CSP plant nearby Shenzhen and Shanghai. The solar salt (NaNO3-KNO3, 60-40 wt.%) has lower LCOE than the other three new molten-salts. In order to calculate the time when the grid parity would be reached, four scenarios for CSP development roadmap proposed by International Energy Agency (IEA) were considered in this study. It was found that the LCOE of tower CSP would reach the grid parity in the years of 2038–2041 in the case of no future penalties for the CO2 emissions. This study can provide support information for the Chinese government to formulate incentive policies for the CSP industry.

Transparent conductive tantalum doped tin oxide as selectively solar-transmitting coating for high temperature solar thermal applications

The transparent conductive oxide (TCO) SnO2:Ta is developed as a selectively solar-transmitting coating for concentrated solar power (CSP) absorbers. Upon covering with an antireflective layer, a calculated absorptivity of 95% and an emissivity of 30% are achieved for the model configuration of SnO2:Ta on top of a perfect black body (BB). High-temperature stability of the developed TCO up to 1073 K is shown in situ by spectroscopic ellipsometry and Rutherford backscattering spectrometry. The universality of the concept is demonstrated by transforming silicon and glassy carbon from non-selective into solar-selective absorbers by depositing the TCO on top of them. Finally, the energy conversion efficiencies of SnO2:Ta on top of a BB and an ideal non-selective BB absorber are extensively compared as a function of solar concentration factor C and absorber temperature TH. Equal CSP efficiencies can be achieved by the TCO on BB configuration with approximately 50% lower solar concentration. This improvement could be used to reduce the number of mirrors in a solar plant, and thus, the levelized costs of electricity for CSP technology.

Current energy mix and techno-economic analysis of concentrating solar power (CSP) technologies in Malaysia

This study performs a techno-economic analysis of concentrating solar power (CSP) technologies for Malaysia. The solar resource assessment was done by analyzing various rural and regional locations using NASA Surface Meteorology and Solar Energy database. Three different technologies, parabolic trough collector (PTC), solar power tower (SPT) and solar parabolic dish (SPD) were assessed under different economic criterions. Results based on the analysis show that PTC and SPT type plants are particularly suitable for locations at East and Peninsular Malaysia. However, considering simple payback, the net present value (NPV) and internal rate of return (IRR), it is found that PTC type CSP plant will be the most eligible for CSP plant development. Sensitivity analysis is performed to investigate the effect of the levelized cost of electricity (LCOE) on the various project discount rate. Regional renewable energy policy development and regulatory reform in feed-in-tariff (FiT), hybrid technology (PTC with biogas, solar PV and biomass) implementation, project financing under clean development mechanism (CDM) and lesson learned from international experience in local PTC equipment manufacturing are some of the crucial future policy outlooks that need to be applied for CSP technology implementation, as well as long-term sustainable renewable energy system development in the country.

Environment impact of a concentrated solar power plant

More recently, there has been an increasing interest in the use of concentrated solar thermal energy for the production of electricity, but also for the use in cogeneration and trigeneration. In this sense, the increasing use of solar thermal energy in urban areas is expected, and its impact on the environment is inducing an increasing interest. The paper analyses the impact of concentrated solar power technology (linear Fresnel, parabolic trough, parabolic dish, and central tower) on the environment in terms of water consumption, land use, wasted heat, emissions of gases, emissions of pollutants that include the leakage of heat transfer fluid through pipelines and tanks, impact on flora and fauna, impact of noise and visual impact. The impact on the environment is different for different concentrated solar power technologies and depends on whether thermal energy storage is included in the plant. Water is mainly used for cooling the system, but also for cleaning the surface of the mirror. To reduce water consumption, other cooling technologies (e.g. air cooling) are being developed. The available data from the literature show large variances depending on the size of the plant, geographic location and applied technology.

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.

A case study on combined cycle power plant integrated with solar energy in Trinidad and Tobago

Aim of the paper is to evaluate the benefit of a renewable energy initiative for Trinidad and Tobago. Trinidad and Tobago have abundant natural gas, a highly developed power generation system almost entirely based on combustion fuels, high solar irradiation, but skies often covered by clouds, a detrimental factor for concentrated solar power technologies. The simple, consolidated, parabolic trough technology, without the addition of thermal energy storage, has the potential to deliver better than solar photovoltaic capacity factors at a comparable cost when mass produced. Integration with natural gas combustion may permit to address the issues of clouds coverage. A computational analysis is proposed for an Integrated Solar Combined Cycle power plant comprising a reference combined cycle gas turbine plant, and a small solar field, located in Trinidad and Tobago. The simulations demonstrate the advantages, in terms of fuel conversion efficiency, of the small solar field addition. On average over the year, the plant operates over the morning and afternoon periods, of length about 8 h a day, at an efficiency of 57.34%, about 2.58% better, and over the mid-day periods, of length about 4 h a day, at an efficiency of 57.97%, about 3.16% better.

Risk management and policy implications for concentrating solar power technology investments in Tunisia

Concentrating solar power (CSP) is a promising technology in Tunisia. However, its diffusion is facing many barriers which deter investments. Through the analysis of a CSP plant in Southern Tunisia by using the Global Risk Analysis (GRA) method, we try to analyze the main risks faced by investors. The main objective of this research is to identify and analyze the risks faced by CSP investors in Tunisia and develop strategies that should be adopted to accelerate the process of diffusion of this technology.This analysis allows us to conclude that the CSP project is very exposed to political, financial, physical-chemical, legal, and strategic hazards. Moreover, we show that among the four phases of the project, the preparation phase is the most vulnerable to hazards.In fact, the GRA method makes it possible to determine the list of the major risks, such as the risk of not obtaining permission to build a CSP plant, the risk of non compliance with the deadline, the risk of failure to achieve the expected performance, the risk of insufficient access to capital, and the risk of conflicts with local residents.In order to de-risk CSP technology in Tunisia, we propose some strategies, such as strengthening the public-private partnerships, using participatory approaches, creating local employment, etc.

Potential of Renewable Energy Resources with an Emphasis on Solar Power in Iraq: An Outlook

This study presents an outlook on the renewable energies in Iraq, and the potential for deploying concentrated solar power technologies to support power generation in Iraq. Solar energy has not been sufficiently utilized at present in Iraq. However, this energy source can play an important role in energy production in Iraq, as the global solar radiation ranging from 2000 kWh/m2 to a 2500 kWh/m2 annual daily average. In addition, the study presents the limited current solar energy activities in Iraq. The attempts of the Iraqi government to utilize solar energy are also presented. Two approaches for utilizing concentrated solar power have been proposed, to support existing thermal power generation, with the possibility of being implemented as standalone plants or being integrated with thermal power plants. However, the cost analysis has shown that for 50 kW concentrated solar power in Iraq, the cost is around 0.23 US cent/kWh without integration with energy storage. Additionally, notable obstacles and barriers bounding the utilization of solar energy are also discussed. Finally, this study proposes initiatives that can be adopted by the Iraqi government to support the use of renewable energy resources in general, and solar energy in particular.

Theoretical and technical potential evaluation of solar power generation in Iran

Nowadays, utilizing solar energy for power production at high efficiency and in a cost-effective status is a challenging issue for power plant engineers. This challenge would be answered by considering several affecting parameters such as technical, economic, and environmental criteria. In this investigation, in order to provide an assessment for implementing solar power plants in the southeast of Iran, Sistan and Baluchistan province, a multi-criteria decision making (MCDM) approach is linked to a geographic information system (GIS). The MCDM approach is used to appraise the effective criteria for implementing solar power plants. The environment, orography, economic and climate are selected as the important criteria. Each criterion is assessed for the defined location of the investigation (Sistan and Baluchistan province) and in addition, GIS is employed to provide a geographical-graphical valuation to determine the most appropriate place for installing a large-scale solar power production plant. The solar systems considered in this study are photovoltaic (PV) collectors and concentrated solar power (CSP) generation plants (e.g. solar trough collectors). Technical and theoretical valuations are made to specify the amount of solar power which can be harnessed in Sistan and Baluchistan. In overall, it is demonstrated that this specific location in the southeast of Iran has the technical potential to provide 7,419 TWh/y and 8,758 TWh/y of solar electricity by installing CSP and PV technologies, respectively.

Dinitrogen tetroxide and carbon dioxide mixtures as working fluids in solar tower plants

The competitiveness of concentrated solar power technology in the near-future electricity generation scenario, requires a substantial reduction of the Levelized Cost of Energy which can be achieved with an increase of the energy conversion efficiencies while maintaining or reducing the investment costs. This paper discusses the use of pure Dinitrogen tetroxide N2O4, and N2O4/CO2 mixture, as working fluids in supercritical Brayton cycles applied to solar tower power plants. When N2O4 is combined with CO2, the resulting mixture has a comparatively higher critical temperature than pure CO2, allowing a condensing cycle even at the fairly high ambient temperatures of desert areas, where solar power plants are typically installed. This allows the adoption of simpler cycle configurations than the one used in sCO2 cycles (cost reduction) while achieving very high thermodynamic efficiency (47% at 700 °C). The N2O4/CO2 mixture with optimized composition, integrated in a solar tower unit, increases the solar-electric efficiency by 1% with respect to commercial plants based on steam cycle with 550 °C maximum temperature (22.3% vs. 21.3%). At 700 °C, the overall solar-electric efficiency can reach 24.5% which is slightly higher than supercritical CO2 cycles, yet with a foreseeable reduction of the investment costs as consequence of the simpler plant lay-out.

Acceptance criteria for accelerated aging testing of silvered-glass mirrors for concentrated solar power technologies

Solar reflectors for Concentrating Solar Power (CSP) technologies are required to maintain their optical properties in demanding environments for more than 20 years of service-life. The durability of the commonly used silvered-glass reflectors is typically qualified by means of accelerated aging. Recently, the Spanish standardization committee UNE has published the first specific standard for this topic, which defines a set of accelerated aging tests for CSP reflectors. However, the standard does not contain pass/fail criteria. This paper proposes useful acceptance criteria for the accelerated tests defined by UNE, helping to interpret the obtained degradation results. The criteria have been determined by analyzing the collected accelerated aging data over the past 5 years in the OPAC laboratory, a joint research group of DLR and CIEMAT. Data from six different 4 mm silvered-glass manufacturers is presented, covering nearly the entire market of commercially available silvered-glass mirrors, and going way beyond the recommended testing times of the UNE standard. The data may be used to benchmark initial reflective properties (before aging) and the performance during accelerated durability testing. In addition, recommendations for improvements of the standard are given and an estimate of the acceleration factor of the Copper Accelerate Salt Spray (CASS) test with respect to a highly corrosive outdoor environment is presented.

Numerical Investigations on Charging/Discharging Performance of a Novel Truncated Cone Thermal Energy Storage Tank on a Concentrated Solar Power System

Developing a concentrated solar power (CSP) technology is one of the most effective methods to solve energy shortage and environmental pollution all over the world. Thermal energy storage (TES) system coupling with phase change materials (PCM) is one of the most significant methods to mitigate the intermittence of solar energy. In this paper, firstly, a 2D physical and mathematical model of a novel truncated cone shell-and-tube TES tank has been proposed based on enthalpy method. Secondly, the performance during the charging/discharging process of the truncated cone tank has been compared with the traditional cylindrical tank. Finally, the effects of inlet conditions of heat transfer fluid (HTF), and thickness of tube on the charging/discharging process, stored/released energy capacity; energy storage/release rate and heat storage efficiency have been investigated. The results show that the performance of truncated cone tank is better, and the charging/discharging time reduces 32.08% and 21.59%, respectively, compared with the cylindrical tank. The effect of wall thickness on the truncated cone TES tank can be ignored. And the inlet temperature and velocity of HTF have the significant influence on the charging/discharging performance of TES tank. And the maximum heat storage efficiency of the truncated cone TES tank can reach 93%. However, some appropriate methods should be taken for improving the thermal energy utilization rate of HTF in the future. This research will provide insights and significant reference towards geometric design and operating conditions in TES system.

Thermodynamic feasibility analysis of a water-splitting thermochemical cycle based on sodium carbonate decomposition

A novel water-splitting thermochemical cycle for the production of green hydrogen is introduced. This three-step cycle is based on the thermal decomposition of sodium carbonate. In this work, thermodynamic equilibrium analysis of the cycle's constituent reactions is performed, for a variety of temperatures, pressures, and dilution ratios. Feasible temperature/pressure/dilution operating windows are identified for the cycle's reactions such that the maximum temperature of the cycle can be generated using current concentrated solar power (CSP) technologies, thus enabling the replacement of steam methane reforming (SMR) as the major industrial production method of hydrogen.

Hybrid-CSP in India: Technological and Economic Aspects

India has an enormous potential for employing concentrated solar power (CSP) technology for energy generation. A great advantage of CSP is that it can be conveniently installed in parallel with existing fossil fuel power plants to deliver a synergetic setup, which will enable us to increase the efficiency of the existing plants without making major changes in the plant setup and machinery. India has not yet utilised this resource to its full capacity. This paper discusses the status of CSP in India and the possible ways in which we can hybridize it with the existing coal plants in Uttar Pradesh (A state of the India) by simulating and optimizing different CSP technology and their economic feasibility. In this various hybrid, CSP technologies linked with different energy resources are discussed in detail. Further, the methodology of the system and different factors and aspects of the technology are discussed, that affect the performance and efficiency of the system. Policies by the government also play a major role in the development of the solar technology in a country, without the support of the government it is very difficult for public and private sector companies to venture in this field of technology, as the initial investment is eminent. Jawaharlal Nehru National Solar Mission (JNNSM), its policies, and how it has exerted a major influence in renewable, especially the solar sector in India in the past decade has been established. The various environment conditions like solar direct normal irradiance, wind-speed, land availability and economic factors like fixed cost expenses, inflation have been considered and areas suitable for CSP technology has been identified.

Assessment of concentrated solar power (CSP) technologies based on a modified intuitionistic fuzzy topsis and trigonometric entropy weights

Concentrated solar power (CSP) technology has shown considerable long-term growth with varying levels of peak development and stall phases over the years. More and more countries are finding CSP technology attractive for the production of electricity and other applications. CSP offers a variety of applications where solar power can be used appropriately, although the debate about which CSP technology has a better future perspective is still ongoing. This technology sector has seen a multitude of advancements and technological innovations. These improvements are primarily concerned with the design of the collectors and the related materials they are made from, the heat transfer processes, and the production and accumulation of energy.In order to assess these CSP technologies, in this paper we propose a fuzzy multi-criteria method. Then, Solar tower (ST), Parabolic solar trough (PST), Compact linear Fresnel reflector (CLFR), and Dish Stirling (DS) are evaluated using a modified intuitionistic fuzzy TOPSIS with a trigonometric entropy vector weight.

Life cycle sustainability analysis applied to an innovative configuration of concentrated solar power

PurposeLife cycle sustainability analysis (LCSA) is being developed as a holistic tool to evaluate environmental, economic and social impacts of products or services throughout their life cycle. This study responds to the need expressed by the scientific community to develop and test LCSA methodology, by assessing the sustainability of a concentrated solar power (CSP) plant based on HYSOL technology (an innovative configuration delivering improved efficiency and power dispatchability).MethodsThe methodology proposed consists of three stages: goal and scope definition, modelling and application of tools, and interpretation of results. The goal of the case study was to investigate to what extent may the HYSOL technology improve the sustainability of power generation in the Spanish electricity sector. To this purpose, several sustainability sub-questions were framed and different analysis tools were applied as follows: attributional and consequential life cycle assessment, life cycle cost (LCC) analysis and multiregional input-output analysis (MRIO), and social life cycle assessment (S-LCA) in combination with social risk assessment (with the Social Hotspots Database). Visual diagrams representing the sustainability of the analysed scenarios were also produced to facilitate the interpretation of results and decision making.Results and discussionThe results obtained in the three sustainability dimensions were integrated using a “questions and answers” layout, each answer describing a specific element of sustainability. The HYSOL technology was investigated considering two different operation modes: HYSOL BIO with biomethane as hybridization fuel and HYSOL NG with natural gas. The results indicated that the deployment of HYSOL technology would produce a reduction in the climate change impact of the electricity sector for both operation modes. The LCC analysis indicated economic benefits per MWh for a HYSOL NG power plant, but losses for a HYSOL BIO power plant. The MRIO analysis indicated an increase in goods and services generation, and value added for the HYSOL technology affecting primarily Spain and to a lower extent other foreign economies. The social analysis indicated that both alternatives would provide a slight increase of social welfare Spain.ConclusionsThe methodological approach described in this investigation provided flexibility in the selection of objectives and analysis tools, which helped to quantify the sustainability effect of the system at a micro and meso level in the three sustainability dimensions. The results indicated that the innovation of HYSOL power plants is well aimed to improve the sustainability of CSP technology and the Spanish electricity sector.

Novel solid–solid phase-change cascade systems for high-temperature thermal energy storage

In this work, we investigate novel solid–solid phase-change cascade systems based on mixtures of lithium and sodium sulfates. Solid–solid phase-change materials (PCMs) can be coupled with concentrated solar power technologies. They present several advantages over solid–liquid PCMs including lower thermal expansion, lower or no corrosiveness, and no need for encapsulation. In solid–solid PCMs, the energy is stored during crystal structure transitions. Specifically, lithium sulfate undergoes a crystal structure transition (monoclinic to cubic) at 576 °C, which is a suitable temperature for concentrated solar thermal technologies. Due to the high cost of lithium sulfate, we evaluated the potential of mixing lithium with sodium sulfate to create solid–solid cascaded PCM systems to provide higher thermal storage densities. We used differential scanning calorimetry, high-temperature in situ X-ray diffraction and thermogravimetric analysis to evaluate the phase-transition temperature, phase-change enthalpy, specific heat capacity, crystalline phase composition and thermal expansion. The obtained values for heat capacity and enthalpies of phase transitions showed good agreement with available thermodynamic databases. Therefore, further calculations of thermodynamic properties of each mixture in the system were performed for designing cascaded latent thermal energy storage system. From the PCM mixtures studied, NaLiSO4 shows the greatest stability under ambient conditions. A mixture of 59.17% NaLiSO4 and 40.83% Li2SO4 allows an optimum charge of both PCMs for power cycles such as supercritical CO2. Economic assessment revealed that this cascade system has an estimated cost of $50.2 kWhth−1.