Integrated Solar Combined Cycle System Research Articles

Instantaneous performance of the first Integrated Solar Combined Cycle System in Algeria

Abstract There is a great interest in the development of renewable energies and more particularly in solar energy. This study arises in midst of construction of the first integrated solar combined cycle system (ISCCS) in Algeria. In the present work, an integrated plant with simple pressure level is proposed and the preferred method for converting solar energy into electricity is applied. Thermal efficiency, electricity production and net solar electricity are the main parameters to evaluate the instantaneous performance of each component of the solar power station through a year. The simulation results show that the power plant can provide about 134MW with efficiency equals 57.5% at night. At daytime, the net solar electricity ratio can be very interested and reach the limit of 15% at the design point. As a result, the output from and the efficiency of the ISCCS will be above the combined cycle regime by 17 and 16.5%, which are correspond to 157MW and 67%, respectively. Increasing of steam turbine capacity by 50% at the design point is other advantage of the proposed design.

Exergy analysis of an integrated solar combined cycle system

Exergetic analysis has become an integral part of thermodynamic assessment of any power generation system. Energy and exergy studies for power plants optimum design and for combined chemical industries received much attention recently. An Integrated Solar Combined Cycle System (ISCCS) is proposed as a means of integrating a parabolic trough solar thermal plant with modern combined cycle power plants. In this study attempt will be made to analyze the Integrated Solar Combined Cycle in Yazd, Iran using design plant data. Energy and exergy analysis for the solar field and combined cycle is carried out to assess the plant performance and pinpoint sites of primary exergy destruction. Exergy destruction throughout the plant is quantified and illustrated using an exergy flow diagram, and compared to the energy flow diagram. The causes of exergy destruction in the plant include: losses in combustor, collector, heat exchangers, and pump & turbines which accounts for 29.62, 8.69, 9.11 and 8% of the total exergy input to the plant, respectively. Exergetic efficiencies of the major plant components are determined in an attempt to assess their individual performances.

Technical and economic assessment of the integrated solar combined cycle power plants in Iran

Thermal efficiency, capacity factor, environmental considerations, investment, fuel and O&M 2 2 Operation and maintenance. costs are the main parameters for technical and economic assessment of solar power plants. This analysis has shown that the Integrated Solar Combined Cycle System with 67 MW e solar field (ISCCS-67) is the most suitable plan for the first solar power plant in Iran. The Levelized Energy Costs (LEC) of combined cycle and ISCCS-67 power plants would be equal if 49 million $ of ISCCS-67 capital cost supplied by the international environmental organizations such as Global Environmental Facilities (GEF) and World Bank. This study shows that an ISCCS-67 saves 59 million $ in fuel consumption and reduces about 2.4 million ton in CO 2 emission during 30 years operating period. Increasing of steam turbine capacity by 50%, and 4% improvement in overall efficiency are other advantages of ISCCS-67 power plant. The LEC of ISCCS-67 is 10 and 33% lower than the combined cycle and gas turbine, respectively, at the same capacity factor with consideration of environmental costs.

Trough integration into power plants—a study on the performance and economy of integrated solar combined cycle systems

Parabolic trough solar technology has been proven at nine commercial Solar Electric Generating Systems (SEGS) power plants that are operating in the California Mojave desert. These plants utilize steam Rankine cycle power plants, and as a result, most people associate parabolic trough solar technology with steam Rankine cycle power plant technology. Although these plants are clearly optimized for their particular application, other power cycle designs may be appropriate in other situations. Of particular interest is the integration of parabolic trough solar technology with combined cycle power plant technology. This configuration is referred to as integrated solar combined cycle systems (ISCCS). Four potential projects in India, Egypt, Morocco, and Mexico are considering the ISCCS type solar power cycle configurations. The key questions are when is the ISCCS configuration preferred over the SEGS power cycle configuration and how is the ISCCS plant designed to optimize the integration of the solar field and the power cycle. This paper reviews the results of a collaborative effort under the International Energy Agency SolarPACES organization to address these questions and it shows the potential environmental and economic benefits of each configuration.

Economic analysis of integrated solar combined cycle power plants: A sample case: The economic feasibility of an ISCCS power plant in Egypt

An integrated solar combined cycle system (ISCCS) was technically and economically studied for implementation in Egypt with support from the global environment facility (GEF). Both, parabolic trough collector field and volumetric air receiver tower were considered as solar systems. The analysis yielded the net present values (NPV) of the project variants, the incremental solar cost, and the levelised electricity cost (LEC) for both the total and the solar electricity productions. For reference, a fossil fired combined cycle (CC) power plant of identical annual total electricity production following the same daily load profiles was assumed. The total (mixed) LEC is equal for both ISCCS variants: 3.1 US¢/kWh. The solar LEC is 9.5 US¢/kWh for HTF-trough and 10.2 US¢/kWh for air-tower. The LEC for the reference CC is 2.4 US¢/kWh. A sensitivity analysis evaluated the impacts of changes in discount rate, solar investment, grant disbursement and fuel price on the LEC. The predicted solar incremental cost of both project variants is within the 50 million US$ limit set by the World Bank for a grant from the GEF. The project provides an environmentally beneficial and economically attractive option for renewable power generation in Egypt.

Thermoeconomic Analysis of Advanced Solar-Fossil Combined Power Plants

Hybrid solar thermal power plants (with parabolic trough type of solar collectors) featuring gas burners and Rankine steam cycles have been successfully demonstrated by California's Solar Electric Generating System (SEGS). This system has been proven to be one of the most efficient and economical schemes to convert solar energy into electricity. Recent technological progress opens interesting prospects for advanced cycle concepts: a) the ISCCS (Integrated Solar Combined Cycle System) that integrates the parabolic trough into a fossil fired combined cycle, which allows a larger exergy potential of the fuel to be converted. b) the HSTS (Hybrid Solar Tower System) which uses high concentration optics (via a power tower generator) and high temperature air receivers to drive the combined cycle power plant. In the latter case, solar energy is used at a higher exergy level as a heat source of the topping cycle. This paper presents the results of a thermoeconomic investigation of an ISCCS envisaged in Tunisia. The study is realized in two phases. In the first phase, a mixed approach, based on pinch technology principles coupled with a mathematical optimization algorithm, is used to minimize the heat transfer exergy losses in the steam generators, respecting the off design operating conditions of the steam turbine (cone law). In the second phase, an economic analysis based on the Levelized Electricity Cost (LEC) approach was carried out for the configurations, which provided the best concepts during the first phase. A comparison of ISCCS with pure fossil fueled plants (CC+GT) is reported for the same electrical power load. A sensitivity analysis based on the relative size of the solar field is presented. This paper was presented at the ECOS'00 Conference in Enschede, July 5-7, 2000

Approche de conception et d'optimisation de centrale solaire intégrée à cycle combiné inspirée de la méthode du pincement (partie I: paliers de récupération)

Integrated solar combined cycle systems (ISCCS) represent, both economically and energetically, a promising alternative for the conversion of solar energy while offering a guarantee of a minimum power supply independent of the level of solar radiation. Their performances are, however, strongly dependent on the intensity of the solar input. The approach proposed in this paper allows, from the characteristics of the turbines (gas turbines and steam turbines) and of the solar field, to rationalize the choice of the pressure levels and of the massflows of a steam cycle with multiple pressure levels. It is based on the coupling of a pinch technology approach with a thermodynamic modelling, allowing an optimisation with deterministic algorithms. Results are applied to a dual pressure steam cycle and account for the respect of the ‘cone law’ for steam turbines. It is shown that an increase of the exergetic losses linked to heat transfer in the steam generators is inevitable at certain operational regimes and depends directly on the level of solar supply. The variations of the main steam cycle parameters as a function of the thermal supply (combustion gases + solar thermal oil) are shown for an 80 to 120 MWe power plant equipped with two gas turbines and one steam turbine train.