Identifying opportunities for developing CSP and PV-CSP hybrid projects under current tender conditions and market perspectives in MENA – benchmarking with PV-CCGT

Concentrating solar power (CSP) is one of the promising renewable energy technologies provided the fact that it is equipped with a cost-efficient storage system, thermal energy storage (TES). This solves the issue of intermittency of other renewable energy technologies and gives the advantage of achieving higher capacity factors and lower levelized costs of electricity (LCOE). This is the main reason why solar tower power plants (STPP) with molten salts and integrated TES are considered one of the most promising CSP technologies in the short term [1]. On the other hand, solar photovoltaic (PV) is a technology whose costs have been decreasing and are expected to continue doing so thus providing competitive LCOE values, but with relatively low capacity factors as electrical storage systems remain not cost-effective. Combining advantages and eliminating drawbacks of both technologies (CSP and PV), Hybridized PV-CSP power plants can be deemed as a competitive economic solution to offer firm output power when CSP is operated smartly so that its load is regulated in response to the PV output. Indeed previous works, have identified that it would allow achieving lower LCOEs than stand-alone CSP plants by means of allowing it to better utilize the solar field for storing energy during the daytime while PV is used [1]. On the fossil-based generation side, the gas turbine combined cycle (CCGT) occupies an outstanding position among power generation technologies. This is due to the fact that it is considered the most efficient fossil fuel-to-electricity converter, in addition to the maturity of such technology, high flexibility, and the generally low LCOE, which is largely dominated by fuel cost and varies depending on the natural gas price at a specific location. Obviously, the main drawback is the generated carbon emissions. In countries rich in natural gas resources and with vast potential for renewable energies implementation, such as the United Arab Emirates (UAE), abandoning a low LCOE technology with competitively low emissions – compared to coal or oil - and heading to costly pure renewable generation, seems like an aggressive plan. Therefore, hybridizing CCGT with renewable generation can be considered an attractive option for reducing emissions at reasonable costs. This is the case of the UAE with vast resources of both natural gas and solar energy. Previous work have shown the advantages of hybrid PV-CCGT and hybrid PV-CSP plants separately [1][2]. In this thesis, CSP and the two hybrid systems are compared on the basis of LCOE and CO2 emissions for a same firm-power capacity factor when considering a location in the UAE. The results are compared against each other to highlight the benefits of each technology from both environmental and economic standpoints and provide recommendations for future work in the field. The techno-economic analysis of CSP (STPP with TES), PV-CSP(STPP with TES) and PV-CCGT power plants have been performed by DYESOPT, an in-house tool developed in KTH, which runs techno-economic performance evaluation of power plants through multi-objective optimization for specific locations[1]. For this thesis, a convenient location in the UAE was chosen for simulating the performance of the plants. The UAE is endowed by the seventh-largest proven natural gas reserves and average to high global horizontal irradiation (GHI) and direct normal irradiation (DNI) values all year round, values considered to be lower than other countries in the MENA region due to its high aerosol concentrations and sand storms. The plants were designed to provide firm power in two cases, first as baseload, and second as intermediate load of 15 hours from 6:00 until 21:00. The hours of production were selected based on a typical average daily load profile. CSP and PV-CSP model previously developed by [3][1] were used. Ideally in the PV-CSP model, during daytime hours the PV generation is used for electricity production, covering the desired load, while CSP is used partly for electricity production and the rest for storing energy in the TES. Energy in the TES system is then used to supply firm power during both periods of low Irradiance and night hours or according to need. A PV-CCGT model has been developed which operates simultaneously, prioritizing the availability of PV while the CCGT fulfils the remaining requirement. There is a minimum loading for the CCGT plant which is determined by the minimum possible partial loading of the gas turbine restricted by the emission constraints. Accordingly, in some cases during operation PV is chosen to be curtailed due to this limitation. The main results of the techno-economic analysis are concluded in the comparative analysis of the 3 proposed power plant configurations, where the PV-CCGT plant is the most economic with minimum LCOE of 86 USD/MWh, yet, the least preferable option in terms of carbon emissions. CSP and PV-CSP provided higher LCOE, while the PV-CSP plant configuration met the same capacity factor with 11% reduction in LCOE, compared to CSP

Dynamic Modeling of a Parabolic Trough Solar Power Plant

Models for dynamic simulation of a parabolic trough concentrating solar power plant were developed in Modelica for the simulation software Dymola. The parabolic trough power plant has a two-­‐tank indirect thermal storage with solar salt for the ability to dispatch electric power later in the evening and during the night when little or no solar irradiation is present. The complete system consists of models for incoming solar irradiation, a parabolic trough collector field, thermal storage and a simplified Rankine cycle. A parabolic trough power plant named Andasol located in Aldeire y La Calahorra, Spain, is chosen as a reference system when the complete system model is designed and built in Dymola. The system model is later validated against performance numbers from this reference system in order to make sure a correct implementation has been made. The collector and solar model have also been validated against different papers regarding solar collector performance and show good results. Finally the system in Dymola has been simulated during a day for different parts of the year with solar data from the same region as the Andasol power plant. The results from these simulations show similarities to how the Andasol power plant operates and how well the system performs under different solar irradiance conditions. By modeling the system dynamically the changes in insolation over time can be studied to gain information about how it affects the system model in detail. Plant startup time and how long the system can be running on the thermal storage is other parameters that could be studied with this dynamic model

Techno-economical analyses of linear solar thermal electric plants for dispatchable power generation

Laut Prognosen wird im Zeitraum von 2018 bis 2023 voraussichtlich 1000 GW neue Stromerzeugungskapazität aus erneuerbaren Energien errichtet, die aber zum größten Teil aus intermittierenden Stromerzeugungstechnologien wie Fotovoltaik und Wind bestehen wird, was das Integrationspotenzial im globalen Stromversorgungssystem einschränkt. Bei Solarthermischen Kraftwerken mit thermischer Energiespeicherung dagegen kann die Stromerzeugung von der variablen Verfügbarkeit der Ressource Sonnenenergie entkoppelt werden, wodurch deutlich geringere Einschränkungen hinsichtlich des Intergrationspotenzials bestehen. Bereits die erste Generation solcher Kraftwerke hat die technische Machbarkeit und die Vorteile dieser Technologie nachgewiesen. Allerdings weist diese erste Technologiegeneration noch zahlreiche Nachteile auf, die ihre Wettbewerbsfähigkeit beeinträchtigt, vor allem auf Grund der physikalischen Eigenschaften des eingesetzten Wärmeträgermediums und der Grundauslegung des hydraulischen Kreislaufs. Weitere Wärmeträgermedien, wie Salzschmelze oder Flüssigmetall, helfen diese Nachteile zu überwinden, insbesondere im Zusammenhang mit sogenannten "Direkt" Kraftwerkskonzepten, bei welchen das selbe Wärmeträgermedium sowohl im Solarfeld als auch im Energiespeicher, also innerhalb eines hydraulischen Kreislaufs, eingesetzt wird. Solche neuen Kraftwerkskonzepte wurden allerdings noch nicht in kommerziellen Kraftwerken mit linienfokussierenden Sonnenkollektoren (wie linear-Fresnel oder Parabolrinne) eingesetzt, weshalb hier weitere Untersuchungen erforderlich sind. Diese Arbeit untersucht den Einfluss ausgewählter Konfigurationsparameter von linienfokussierenden Kraftwerken mit Salzschmelze als Wärmeträgermedium nach dem "Direkt" Kraftwerkskonzept auf deren Stromgestehungskosten und vergleicht dieses Kraftwerkskonzept mit dem Stand der Technik und weiteren Kraftwerkskonzepten mit Flüssigmetall als Wärmeträgermedium. Zu diesem Zweck wurde eine neue Simulationsumgebung entwickelt, um einen Kraftwerksbetrieb über den Zeitraum eines Jahres mit relativ hoher Zeitauflösung (ein bis fünf Minuten) zu simulieren, um den Stromertrag und die Kosten des Kraftwerks genauer berechnen zu können. Zur Verifizierung der Berechnungsergebnisse dieses Modells wurde ein Abgleich mit genaueren Modellen und Daten aus der Fachliteratur vorgenommen, woraus eine relative Ungenauigkeit hinsichtlich der Simulationsergebnisse des Stromertrags von weniger als 5% geschätzt werden kann. Mit diesem Simulationsmodell wurden technisch-wirtschaftliche Analysen der Hauptkonfigurationsparameter von einem linear-Fresnel Kraftwerk mit "Direkt" Kraftwerkskonzept und Salzschmelze durchgeführt, die unter anderem gezeigt haben, dass (a) der Bedarf an thermischer Energie, die erforderlich ist um zu vermeiden, dass die Salzschmelze im Solarfeld gefriert, weniger als 1% des Ertrags der thermische Energie aus dem Solarfeld beträgt, weshalb es nur einen vernachlässigbaren Einfluß auf die Stromgestehungskosten hat; (b) Kraftwerke, die eine Nennleistung von mehr als 200 MW haben, als zwei getrennte Kraftwerke mit jeweils reduzierten Nennleistungen gebaut werden sollen, weil andernfalls die Wärme- und Druckverluste im Solarfeld erhebliche Einbußen im Stromertrag verursachen; (c) eine Nord/Süd Ausrichtung des Solarfelds erhöhte jährliche Stromertragswerte für Standorte mit einem Breitengrad unter 35\degree~bringt, für andere Standorte dagegen eine Ost/West Ausrichtung besser ist und (d) optimale Werte hinsichtlich der Stromgestehungskosten bei einem Nutzungsgrad des Kraftwerks zwischen 60% und 75% (je nach Standort) erreicht werden, was dafür spricht solche Kraftwerke als Mittellastkraftwerke einzusetzen statt als Grundlastkraftwerke. Die Vergleichsanalysen haben gezeigt, dass (a) die Stromgestehungskosten bei dem "Direkt" Kraftwerkskonzept mit Salzschmelze im Vergleich zu thermo-Öl-Kraftwerken, die dem Stand der Technik entsprechen um mindestens 57% reduziert sind und (b) die Stromgestehungskosten bei Kraftwerken mit Flüßigmetall als Wärmeträgermedium, hauptsächlich wegen einer geringeren Dichte, geringerer Wärmekapazität und höherer spezifischer Kosten, um mindestens 25% höher sind

The effects of regional insolation differences upon advanced solar thermal electric power plant performance and energy costs

The performance and cost of four 10 MWe advanced solar thermal electric power plants sited in various regions of the continental United States was studied. Each region has different insolation characteristics which result in varying collector field areas, plant performance, capital costs and energy costs. The regional variation in solar plant performance was assessed in relation to the expected rise in the future cost of residential and commercial electricity supplied by conventional utility power systems in the same regions. A discussion of the regional insolation data base is presented along with a description of the solar systems performance and costs. A range for the forecast cost of conventional electricity by region and nationally over the next several decades is given

The effects of regional insolation differences upon advanced solar thermal electric power plant performance and energy costs

The performance and cost of the 10 MWe advanced solar thermal electric power plants sited in various regions of the continental United States were determined. The regional insolation data base is discussed. A range for the forecast cost of conventional electricity by region and nationally over the next several cades are presented

Concentrated Solar Power Plant for Key Locations in Doha Qatar

One of the pillars of the Qatar National Vision 2030 is the protection and preservation of the environment by decreasing the dependency on hydrocarbon resources and promoting the use and development of renewable energy sources. Moreover, Qatar is located within the sun belt region of the world which receives abundant solar radiation. Thus, solar renewable energy technologies and concentrating solar power (CSP) has a good potential for producing green energy in Qatar. In this thesis, a CSP power tower plant located in Al-Safliya island is designed to power Al-Jasra and Msheireb down town Doha city zones. These two key locations in Doha are with high electricity demand potential. One of the most famous Souqs in Qatar, Souq Waqif, is in Al-Jasra zone. The suggested location of the CSP plant offers a site that is less than 10 km in distance from the targeted zones which means less transmission losses and transmission route cost. Moreover, the location is very near from Hamad International Airport and it can be easily seen during the departures and arrivals flights. The study is based on an actual electrical consumption of more than 600 shops of the Souq measured on year 2014 and 2015. In the CSP technology side, the four main technologies are studied with more focus on the solar tower technology. The main components of this technology are reviewed as well. As a part of the literature review, a data base for all the CSP projects around the world is made and a Microsoft Excel model for calculating the available solar irradiance in any location of the world is prepared. Two softwares are used in this project, SolarPILOT and System Advisor Model (SAM). Both softwares are validated with a recent power tower project. The result of the study is a CSP project with more than 0.45 km2 of a solar field area with 2736 heliostats that produces 8 MWe with 10 hours of thermal storage with hybrid steam condensing system. The water that is required for the plant operation is extracted and desalinated from the surrounded sea using a water treatment system based on a reverse osmosis system. The total electrical production of the plant is found to be 37,904,830 kWh with excess of electrical energy of 28,845,986 kWh, after subtracting the consumption of Souq Waqif. The total system installed cost is found to be $84,069,896. It is broken down as total direct capital cost of$ 73,395,696 and total indirect cost of $10,674,192. The estimated total installed cost per net capacity is found to be$11,120/kW. Finally, one of the main future recommendations is to build an immediate solar and weather station in the state to measures the actual three solar components of the available solar irradiance on both horizontal and dual axes tracking surface

csp pt gas plant using air as heat transfer fluid with a packed bed storage section

Abstract Concentrated Solar Power technologies represent an important alternative able to replace in a medium/long term fossil fuel sources. Current technology has several drawbacks which prevent a large diffusion: the principal one is the choice of the Heat Transfer Fluid which involves a certain complexity, including the heat storage section. Conventional plants in operation, consider diathermic oil and, more recently, molten salts. The potential of gases as working fluid has been underestimated till now and its use has not still fully exploited. Using gas would determinate a simpler conversion section increasing reliability. The gas, as proposed by the authors, can expand directly in a series of inter-reheated turbines after a series of intercooled compressions, reaching an acceptable overall global efficiency of the conversion section. The paper describes the optimum choice for the thermodynamic cycle which approaches an Ericsson cycle, integrating it with a comprehensive mathematical model for the heating section of the gas inside the solar receiver. A Thermal Energy Storage section based on the use of a packed bed of rocks has been considered, merged at the plant to insure production continuity. The overall software platform for the plant can be used as design tool in order to set up most important alternatives related to the plant characteristics and specific parameters