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  • 1.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Preliminary design and analysis of a novel solar receiver for a micro gas-turbine based solar dish system2015In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 114, no 4, 378-396 p.Article in journal (Refereed)
    Abstract [en]

    The solar receiver is one of the key components of hybrid solar micro gas-turbine systems, which would seem to present a number of advantages when compared with Stirling engine based systems and photovoltaic panels. In this study a solar receiver meeting the specific requirements for integration into a small-scale (10 kWel) dish-mounted hybrid solar micro gas-turbine system has been designed with a special focus on the trade-offs between efficiency, pressure drop, material utilization and economic design. A situation analysis, performed using a multi-objective optimizer, has shown that a pressurized configuration, where the solar receiver is placed before the turbine, is superior to an atmospheric configuration with the solar receiver placed after the turbine. Based on these initial design results, coupled CFD/FEM simulations have been performed, allowing detailed analysis of the designs under the expected operating conditions. The results show that the use of volumetric solar receivers to provide heat input to micro gas-turbine based solar dish systems appears to be a promising solution; with material temperatures and material stresses well below permissible limits.

  • 2.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Small Scale Hybrid Solar Power Plants for Polygeneration in Rural Areas2014In: Energy Procedia 57, Elsevier, 2014, Vol. 57, 1536-1545 p.Conference paper (Refereed)
    Abstract [en]

    Small scale micro gas-turbine based hybrid solar power plants are a promising technology for supplying multiple energy services in a controllable and sustainable manner using polygeneration technologies. Compared to a conventional diesel generator based system where electricity is used as the main energy carrier, these systems show great potential to reduce costs and carbon dioxide emissions. Depending on the design, carbon dioxide emissions are reduced by around 9% and equivalent annual costs are reduced by 21% - 26%, as compared to a base polygeneration configuration where cooling services are provided centrally by an absorption chiller without integrating a solar micro gas-turbine. Compared to the system where electricity is used as the main energy carrier a reduction of equivalent annual costs of up to 20% and a reduction of carbon dioxide emissions of up to 33.5% was achieved.

  • 3.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    IMDEA Energy Institute, Spain.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermoeconomic Analysis of a Solar Dish Micro Gas-Turbine Combined-Cycle Power Plant2014In: Proceedings of the International SolarPACES Conference 2014. Beijing, China. September 16-19, Elsevier, 2014Conference paper (Refereed)
    Abstract [en]

    A novel solar power plant concept is presented, based on the use of a coupled network of hybrid solar-dish micro gas-turbines, driving a centralized heat recovery steam generator and steam-cycle, thereby seeking to combine the high efficiency of the solar dish collector with a combined-cycle power block. A 150 MWe solar power plant was designed based on this concept and compared with both a conventional combined-cycle power plant and a hybrid solar-tower combined-cycle. The solar dish combined-cycle power plant could reach higher levels of solar integration than other concepts but was shown to be more expensive with current technology; solar electricity costs are double those of the hybrid solar-tower combined cycle.

  • 4.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Micro Gas-Turbine Design for Small-Scale Hybrid Solar Power Plants2013In: Proceedings of the ASME Turbo Expo 2013. San Antonio, USA. June 3-7, ASME , 2013Conference paper (Refereed)
    Abstract [en]

    Hybrid solar micro gas-turbines are a promising technology for supplying controllable low-carbon electricity in off-grid regions. A thermoeconomic model of three different hybrid micro gas-turbine power plant layouts has been developed, allowing their environmental and economic performance to be analyzed. In terms of receiver design, it was shown that the pressure drop is a key criterion. However, for recuperated layouts the combined pressure drop of the recuperator and receiver is more important. The internally-fired recuperated micro gas-turbine was shown to be the most promising solution of the three configurations evaluated, in terms of both electricity costs and carbon emissions. Compared to competing diesel generators, the electricity costs from hybrid solar units are between 10% and 43% lower, while specific CO2 emissions are reduced by 20 – 35%.

  • 5.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Micro Gas-Turbine Design for Small-Scale Hybrid Solar Power Plants2013In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 135, no 11, 113001- p.Article in journal (Refereed)
    Abstract [en]

    Hybrid solar micro gas-turbines are a promising technology for supplying controllable low-carbon electricity in off-grid regions. A thermoeconomic model of three different hybrid micro gas-turbine power plant layouts has been developed, allowing their environmental and economic performance to be analyzed. In terms of receiver design, it was shown that the pressure drop is a key criterion. However, for recuperated layouts, the combined pressure drop of the recuperator and receiver is more important. In terms of both electricity costs and carbon emissions, the internally-fired recuperated micro gas-turbine was shown to be the most promising solution of the three configurations evaluated. Compared to competing diesel generators, the electricity costs from hybrid solar units are between 10% and 43% lower, while specific CO2 emissions are reduced by 20–35%.

  • 6.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Wang, Wujun
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Design and Analysis of a Solar Receiver for Micro Gas Turbine based Solar Dish Systems2012In: Proceedings of the International SolarPACES Conference 2012. Marrakesh, Morocco. September 11-14, 2012, 2012Conference paper (Refereed)
    Abstract [en]

    The solar receiver is one of the key components of hybrid solar micro gas turbine systems which would seem to present a number of advantages when compared with Stirling engine systems. A solar receiver meeting the specific requirements for integration into the power conversion system of the solar laboratory of the Royal Institute of Technology - which will emulate a solar dish system and is currently under construction - was designed. The simulations that have been performed utilize a heat transfer and pressure drop model coupled with a multi-objective optimizer as well as a coupled-CFD/FEM tool, allowing determination of the ideal receiver design for the expected conditions. The analysis has shown that the use of volumetric solar receivers to provide heat input to micro gas turbine based solar dish systems appears to be a promising solution; with pressurized receiver configurations as the preferred choice due to significant lower pressure drops as compared to atmospheric configurations.

  • 7.
    Ghaem Sigarchian, Sara
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Strand, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Malmquist, Anders
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Modeling and Analysis of a Hybrid Solar-Dish Brayton Engine2012In: Proceedings of the International SolarPACES Conference 2012, 2012Conference paper (Refereed)
    Abstract [en]

    Small-scale recuperated gas turbines with a highly efficient recuperator would appear to have considerable potential to be used in solar/fossil-fuel hybrid dish systems. The hybrid solar gas turbine can be configured in several different fashions, with the key difference being the relative positions of the solar receiver and burner as well as the operation mode of the burner.

    Steady state and transient models have been implemented in Engineering Equation Solver and the performance of various configurations are studied and compared. Layouts in which the receiver is located before the turbine (pressurized receivers) demonstrate higher performance compared to the one in which the receiver is located after the turbine (atmospheric receivers). The variation in operation throughout the year is taken into account and the performance of the system analyzed for two different cities (Yechang in China and Bechar in Algeria, with low and high solar insolation respectively). The integration of a solar receiver into a micro gas turbine reduces the yearly fuel consumption by around 15-16% in Yechang and up to 40% in Bechar. This will result in reductions of CO2 emissions as well as leading to lower daily operating costs. The hybrid nature of the Dish-Brayton system guarantees availability of the engine to meet the electricity demand whenever it occurs, allowing the system to supply dispatchable power.

  • 8.
    Guedez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Enhancing the Economic Competitiveness of Concentrating Solar Power Plants through an Innovative Integrated Solar Combined-Cycle with Thermal Energy Storage2014In: Proceedings of the ASME TurboExpo 2014, 2014, Vol. 3AConference paper (Refereed)
    Abstract [en]

    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.

  • 9.
    Guedez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Reducing the Number of Turbine Starts in Concentrating Solar Power Plants through the Integration of Thermal Energy Storage2015In: Journal of solar energy engineering, ISSN 0199-6231, E-ISSN 1528-8986, Vol. 137, no 2Article in journal (Refereed)
    Abstract [en]

    The operation of steam turbine units in solar thermal power plants is very different than in conventional base-load plants. Due to the variability of the solar resource, much higher frequencies of plant start-ups are encountered. This study provides an insight to the influence of thermal energy storage (TES) integration on the typical cycling operation of solar thermal power plants. It is demonstrated that the integration of storage leads to significant reductions in the annual number of turbine starts and is thus beneficial to the turbine lifetime. At the same time, the effects of storage integration on the electricity costs are analyzed to ensure that the designs remain economically competitive. Large storage capacities, can allow the plant to be shifted from a daily starting regime to one where less than 20 plant starts occur annually. Additionally, the concept of equivalent operating hours (EOHs) is used to further analyze the direct impact of storage integration on the maintenance planning of the turbine units.

  • 10.
    Guedez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Optimization of Thermal Energy Storage Integration Strategies for Peak Power Production by Concentrating Solar Power Plants2014In: PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE, 2014, Vol. 49, 1642-1651 p.Conference paper (Refereed)
    Abstract [en]

    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.

  • 11.
    Guédez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Enhancing the Economic Competitiveness of Concentrating Solar Power Plants Through an Innovative Integrated Solar-Combined Cycle With Thermal Energy Storage2015In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 137, no 4, 041701Article in journal (Refereed)
    Abstract [en]

    The present work deals with the thermo-economic 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 (CCGT) power plants and it is shown that, under specific peaking operating strategies (P-OSs), the innovative concept cannot only perform better from an environmental standpoint but also economically.

  • 12.
    Guédez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermoeconomic Optimization of Solar Thermal Power Plants with Storage in High-Penetration Renewable Electricity Markets2013In: Energy Procedia, 2013, Vol. 57Conference paper (Refereed)
    Abstract [en]

    Unlike most of renewable energy technologies, solar thermal power plants with integrated thermal energy storage are able to store heat from the sun and thereby supply electricity whenever it is needed to meet the demand. This attribute makes concentrating solar power ideally suited to compensate for fluctuations in other renewable energy sources. In order to analyze this market role, three scenarios were modeled, with low, medium and high penetrations of non- dispatchable renewables (i.e. wind and solar photovoltaics). The demand that cannot be met by these variable sources is met by a solar thermal power plant with heat provided either by a solar field and storage system or a back-up gas burner. For each scenario, the size of the solar field and storage were varied in order to show the trade-off between the levelized generation costs of the system, the annual specific CO2 emissions and the share of renewable electricity generation. The results show that, regardless of the scenario, there exist optimum plant configurations with viable costs whilst simultaneously ensuring a considerable reduction in CO2 emissions. Furthermore, it is shown that the limited flexibility of the power block prevents the system from reaching higher levels of sustainability. Lastly, the results were compared with an equivalent combined cycle power plant, showing that solutions involving solar thermal power can be justified in environmental terms only if large storage units are integrated into the plants.

  • 13.
    Guédez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Reducing the Number of Turbine Starts in Concentrating Solar Power Plants through the Integration of Thermal Energy Storage2013In: Proceedings of the ASME TurboExpo 2013, 2013Conference paper (Refereed)
    Abstract [en]

    The operation of steam turbine units in solar thermal power plants is very different than in conventional base-load plants. Due to the variability of the solar resource, much higher frequencies of plant start-ups are encountered. This study provides an insight to the influence of thermal energy storage integration on the typical cycling operation of solar thermal power plants. It is demonstrated that the integration of storage leads to significant reductions in the annual number of turbine starts and is thus beneficial to the turbine lifetime. At the same time, the effects of storage integration on the electricity costs are analyzed to ensure that the designs remain economically competitive. Large storage capacities, can allow the plant to be shifted from a daily starting regime to one where less than 20 plant starts occur annually. Additionally, the concept of equivalent operating hours is used to further analyze the direct impact of storage integration on the maintenance planning of the turbine units.

  • 14.
    Pihl, Erik
    et al.
    Chalmers University of Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Johnsson, Filip
    Chalmers University of Technology.
    Thermoeconomic Optimisation of Solar Hybridisation Options for Existing Combined-Cycle Power Plants2011In: Proceedings of the International SolarPACES Conference 2011, 2011Conference paper (Refereed)
    Abstract [en]

    A model of an integrated solar combined cycle power plant has been developed in order to examine the performance of a combined-cycle plant when retrofitted with solar collectors. The model was then used for multi-objective thermo-economic optimisation of both the power plant performance and cost, using a population-based algorithm. In order to examine the trade-offs that must be made and identify ‘optimal’ hybridisation schemes and operating conditions, two conflicting objectives will be considered, namely minimum investment costs and maximum annual solar share. It was found that only small annual solar shares (~1%) can be achieved during retrofitting, but that the cost of the additional solar-generated electricity is comparably low, with equivalent levelised electricity costs of ≤10 c€/kWh.

  • 15.
    Pihl, Erik
    et al.
    Chalmers University of Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Johnsson, Filip
    Chalmers University of Technology.
    Thermo-Economic Optimization of Hybridization Options for Solar Retrofitting of Combined-Cycle Power Plants2014In: Journal of solar energy engineering, ISSN 0199-6231, E-ISSN 1528-8986, Vol. 136, no 2, 021001- p.Article in journal (Refereed)
    Abstract [en]

    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.

  • 16.
    Salomon Popa, Marianne
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Gómez Galindo, María Fernanda
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Andrew
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Optimization of a Sawmill-Based Polygeneration Plant2013In: Proceedings of the ASME Turbo Expo 2013, ASME Press, 2013Conference paper (Refereed)
    Abstract [en]

    Biomass-based fuels have attracted worldwide interest due to their plentiful supply and their environmentally friendly characteristics. In many cases they are still considered waste but for most industries in Sweden, biomass has changed from being simply a disposal problem to become an important part of the energy supply, thanks to the long-term efforts made by the government, researchers and industry, where energy policies have played an important role. However, the amount of power that could be generated from biomass resources is much greater than that which is currently used. To effectively capture this resource requires a new generation of biomass power plants and their effective integration into already existing industrial processes.The implementation of an integrated polygeneration scheme requires the simultaneous consideration of technical, economic and environmental factors to find optimum solutions. With this in mind, a unified modeling approach that takes into account thermodynamic as well as economic and environmental aspects was used. The analysis was done using ASPEN Utilitiesand the MATLAB optimization toolbox. A specific case of a sawmill in Sweden, with an annual capacity of 130’000 m3 of sawn wood, has been analyzed and different options for generating electricity and process heat (for the sawmill and fora district heating network) as well as densified biofuels was analyzed. Optimization was then applied for different configurations and operational parameters. The results show that the sawmill has the capability to not only supply its own energy needs, but also to export from 0.4 to 1MW of electricity to the grid, contribute 5 to 6 MWth of district heating and 20 000 ton/y of biomass pellets. The production of pellets helps to maintain the electricity production throughout the year when the district heating demand is lower. However, the levelized electricity cost is higher than the usual electricity price in the Nordic electricity market and may have difficulty to competing with low-cost electricity sources, such as nuclear energy and hydropower. Inspite of this, polygeneration remains attractive for covering the energy demands of the sawmill and pelletization plant.

  • 17.
    Sandoz, Raphael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Air-Based Bottoming-Cycles for Water-Free Hybrid Solar Gas-Turbine Power Plants2013In: Proceedings of the ASME TurboExpo 2013, 2013Conference paper (Refereed)
    Abstract [en]

    A thermoeconomic model of a novel hybrid solar gas- turbine power plant with an air-based bottoming cycle has been developed, allowing its thermodynamic, economic, and environmental performance to be analyzed. Multi-objective optimization has been performed to identify the trade-off between two conflicting objectives: minimum capital cost and minimum specific CO2 emissions. In-depth thermoeconomic analysis reveals that the additional bottoming cycle significantly reduces both the levelized cost of electricity and the environmental impact of the power plant (in terms of CO2 emissions and water consumption) when compared to a simple gas-turbine power plant without bottoming cycle. Overall, the novel concept appears to be a promising solution for sustainable power generation, especially in water-scarce areas.

  • 18.
    Sandoz, Raphael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Air-Based Bottoming-Cycles for Water-Free Hybrid Solar Gas-Turbine Power Plants2013In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 135, no 10, 101701- p.Article in journal (Refereed)
    Abstract [en]

    A thermoeconomic model of a novel hybrid solar gas-turbine power plant with an air-based bottoming cycle has been developed, allowing its thermodynamic, economic, and environmental performance to be analyzed. Multi-objective optimization has been performed to identify the trade-offs between two conflicting objectives: minimum capital cost and minimum specific CO2 emissions. In-depth thermoeconomic analysis reveals that the additional bottoming cycle significantly reduces both the levelized cost of electricity and the environmental impact of the power plant (in terms of CO2 emissions and water consumption) when compared to a simple gas-turbine power plant without bottoming cycle. Overall, the novel concept appears to be a promising solution for sustainable power generation, especially in water-scarce areas.

  • 19.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Hybrid Solar Gas-Turbine Power Plants: A Thermoeconomic Analysis2013Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The provision of a sustainable energy supply is one of the most importantissues facing humanity at the current time, and solar thermal power hasestablished itself as one of the more viable sources of renewable energy. Thedispatchable nature of this technology makes it ideally suited to forming thebackbone of a future low-carbon electricity system.However, the cost of electricity from contemporary solar thermal power plantsremains high, despite several decades of development, and a step-change intechnology is needed to drive down costs. Solar gas-turbine power plants are apromising new alternative, allowing increased conversion efficiencies and asignificant reduction in water consumption. Hybrid operation is a furtherattractive feature of solar gas-turbine technology, facilitating control andensuring the power plant is available to meet demand whenever it occurs.Construction of the first generation of commercial hybrid solar gas-turbinepower plants is complicated by the lack of an established, standardised, powerplant configuration, which presents the designer with a large number ofchoices. To assist decision making, thermoeconomic studies have beenperformed on a variety of different power plant configurations, includingsimple- and combined-cycles as well as the addition of thermal energy storage.Multi-objective optimisation has been used to identify Pareto-optimal designsand highlight trade-offs between costs and emissions.Analysis of the simple-cycle hybrid solar gas-turbines revealed that, whileelectricity costs were kept low, the achievable reduction in carbon dioxideemissions is relatively small. Furthermore, an inherent trade-off between thedesign of high efficiency and high solar share hybrid power plants wasidentified. Even with the use of new optimised designs, the degree of solarintegration into the gas-turbine did not exceed 63% on an annual basis.In order to overcome the limitations of the simple-cycle power plants, twoimprovements were suggested: the integration of thermal energy storage, andthe use of combined-cycle configurations. Thermal energy storage allowed thedegree of solar operation to be extended, significantly decreasing carbondioxide emissions, and the addition of a bottoming-cycle reduced the electricitycosts. A combination of these two improvements provided the bestperformance, allowing a reduction in carbon dioxide emissions of up to 34%and a reduction in electricity costs of up to 22% compared to a combination ofconventional power generation technologies.

  • 20.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Steam Turbine Optimisation for Solar Thermal Power Plant Operation2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The provision of a sustainable energy supply is one of the most important issues facing humanity at the current time, given the strong dependence of social and economic prosperity on the availability of affordable energy and the growing environmental concerns about its production. Solar thermal power has established itself as a viable source of renewable power, capable of generating electricity at some of the most economically attractive rates.

    Solar thermal power plants are based largely on conventional Rankine-cycle power generation equipment, reducing the technological risk involved in the initial investment. Nevertheless, due to the variable nature of the solar supply, this equipment is subjected to a greater range of operating conditions than would be the case in conventional systems.

    The necessity of maintaining the operational life of the steam-turbines places limits on the speed at which they can be started once the solar supply becomes available. However, in order to harvest as much as possible of the Sun’s energy, the turbines should be started as quickly as is possible. The limiting factor in start-up speed being the temperature of the metal within the turbines before start-up, methods have been studied to keep the turbines as warm as possible during idle-periods.

    A detailed model of the steam-turbines in a solar thermal power plant has been elaborated and validated against experimental data from an existing power plant. A dynamic system model of the remainder of the plant has also been developed in order to provide input to the steam-turbine model.

    Three modifications that could potentially maintain the internal temperature of the steam-turbines have been analysed: installation of additional insulation, increasing the temperature of the gland steam and use of external heating blankets. A combination of heat blankets and gland steam temperature increase was shown to be the most effective, with increases in electricity production of up to 3% predicted on an annual basis through increased availability of the solar power plant.

  • 21.
    Spelling, James
    et al.
    IMDEA Energy Institute, High Temperature Processes Unit, Móstoles, Spain.
    Aichmayer, Lukas
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermoeconomic Evaluation of a Novel Utility-Scale Hybrid Solar Dish Micro Gas-Turbine Power Plant2015In: Proceedings of the ASME Turbo Expo 2015. Montreal, Canada. June 15-19, ASME Press, 2015Conference paper (Refereed)
    Abstract [en]

    A novel solar power plant concept is presented, based on the use of a coupled network of hybrid solar-dish micro gas-turbines, driving a centralized heat recovery steam generator and steam-cycle, thereby seeking to combine the high collector efficiency of the solar dish with the high conversion efficiency of a combined-cycle power block. To explore the potential of the concept, its performance has been compared against a more conventional solar dish farm based on recuperated micro gas-turbines. Multi-objective optimization has been used to identify Pareto-optimal designs and examine the trade-offs between minimizing capital costs and maximizing performance. The micro gas-turbine combined-cycle layout has been shown to be promising for utility-scale applications, reducing electricity costs by 5–10%, depending on the degree of solar integration; this novel power plant layout also reduces emissions through increased conversion efficiency of the power block. However, at smaller plant sizes (outputs below 18 MWe), more traditional recuperated solar dish farms remain the most viable option.

  • 22.
    Spelling, James
    et al.
    Ecole Polytechnique Fédéral de Lausanne.
    Augsburger, Germain
    Ecole Polytechnique Fédéral de Lausanne.
    Favrat, Daniel
    Ecole Polytechnique Fédéral de Lausanne.
    Evaluation of a Combined-Cycle Setup for Solar Tower Power Plants2009In: Proceedings of the International SolarPACES Conference 2009, Berlin, 2009Conference paper (Refereed)
    Abstract [en]

    Simulation of a pure-solar combined-cycle solar thermal power was performed in order to analyse the thermodynamic and economic performance. An open volumetric receiver and packed-bed storage concept was considered. For a 15 MWe power plant, an exergetic efficiency of 25.6% was obtained based on a typical irradiation profile for a single day. The storage volume used was sized to allow continuous operation of the power generation cycle at its nominal point. Accounting for an amortisation over 15 years, a levelised cost of 17.7 UScts/kWhe is possible.

  • 23.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Ecole Polytechnique Fédérale, Switzerland .
    Favrat, D.
    Martin, Andrew
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Augsburger, G.
    Thermo-economie optimisation of solar tower thermal power plants2010In: Proceedings of the 23rd International Conference on Efficiency, Cost, Optimization, Simulation, and Environmental Impact of Energy Systems, ECOS 2010, Åbo Akademi University Press, 2010, Vol. 2, 353-361 p.Conference paper (Refereed)
    Abstract [en]

    A dynamic model of a pure-solar combined cycle power plant has been developed in order to allow determination of the thermodynamic and economic performance of the plant for a variety of operating conditions and superstructure layouts. The model was then used for multi-objective thermo-economic optimisation of both the power plant performance and cost, using a population-based algorithm. In order to examine the trade-offs that must be made, two, conflicting, objectives will be considered, namely minimal investment costs and minimal levelised energy costs. It was shown that efficiencies lie in the region of 18-24% accompanied by levelised electricity costs in the region of 12-24 UScts/kWhe.

  • 24.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Favrat, Daniel
    Ecole Polytechnique Fédéral de Lausanne.
    Martin, Andrew
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Augsburger, Germain
    Ecole Polytechnique Fédéral de Lausanne.
    Thermo-Economic Optimisation of Solar Tower Thermal Power Plants2010In: Proceedings of the International ECOS Conference 2010, 2010Conference paper (Refereed)
    Abstract [en]

    A dynamic model of a pure-solar combined cycle power plant has been developed in order to allow determination of the thermodynamic and economic performance of the plant for a variety of operating conditions and superstructure layouts. The model was then used for multi-objective thermo- economic optimisation of both the power plant performance and cost, using a population-based algorithm. In order to examine the trade-offs that must be made, two, conflicting, objectives will be considered, namely minimal investment costs and minimal levelised energy costs. It was shown that efficiencies lie in the region of 18-24% accompanied by levelised electricity costs in the region of 12-24 UScts/kWhe.

  • 25.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Favrat, Daniel
    Ecole Polytechnique Fédéral de Lausanne.
    Martin, Andrew
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Augsburger, Germain
    Ecole Polytechnique Fédéral de Lausanne.
    Thermoeconomic optimization of a combined-cycle solar tower power plant2012In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 41, no 1, 113-120 p.Article in journal (Refereed)
    Abstract [en]

    A dynamic model of a pure-solar combined-cycle power plant has been developed in order to allow determination of the thermodynamic and economic performance of the plant for a variety of operating conditions and superstructure layouts. The model was then used for multi-objective thermoeconomic optimization of both the power plant performance and cost, using a population-based evolutionary algorithm. In order to examine the trade-offs that must be made, two conflicting objectives will be considered, namely minimal investment costs and minimal levelized electricity costs. It was shown that efficiencies in the region of 18-24% can be achieved, and this for levelized electricity costs in the region of 12-24 UScts/kWh(e), depending on the magnitude of the initial investment, making the system competitive with current solar thermal technology.

  • 26.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Guedez, Rafael
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A Thermo-Economic Study of Storage Integration in Hybrid Solar Gas-Turbine Power Plants2015In: Journal of solar energy engineering, ISSN 0199-6231, E-ISSN 1528-8986, Vol. 137, no 1Article in journal (Refereed)
    Abstract [en]

    A thermo-economic simulation model of a hybrid solar gas-turbine (HSGT) power plant with an integrated storage unit has been developed, allowing determination of the thermodynamic and economic performance. Designs were based around two representative industrial gas-turbines: a high efficiency machine and a low temperature machine. In order to examine the trade-offs that must be made, multi-objective thermo-economic analysis was performed, with two conflicting objectives: minimum investment costs and minimum specific carbon dioxide (CO2) emissions. It was shown that with the integration of storage, annual solar shares above 85% can be achieved by HSGT systems. The levelized electricity cost (LEC) for the gas-turbine system as this level of solar integration was similar to that of parabolic trough plants, allowing them to compete directly in the solar power market. At the same time, the water consumption of the gas-turbine system is significantly lower than contemporary steam-cycle based solar thermal power plants.

  • 27.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Guedez, Rafael
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    The Value of Storage in Hybrid Solar Gas-Turbine Power Plants2012In: Proceedings of the International SolarPACES Conference 2012, Marrakesh, 2012Conference paper (Refereed)
    Abstract [en]

    A thermoeconomic simulation model of a hybrid solar gas-turbine power plant with an integrated storage unit has been developed, allowing determination of the thermodynamic and economic performance. Designs were based around two representative industrial gas-turbines: a high efficiency machine and a low temperature machine. In order to examine the trade-offs that must be made, multi-objective thermo-economic analysis was performed, with two conflicting objectives: minimum investment costs and minimum specific CO2 emissions. It was shown that with the integration of storage, annual solar shares above 85% can be achieved by hybrid solar gas-turbine systems. The levelised electricity cost for the gas-turbine system as this level of solar integration was similar to that of parabolic trough plants, allowing them to compete directly in the solar power market. At the same time, the water consumption of the gas-turbine system is significantly lower than contemporary steam-cycle based solar thermal power plants.

  • 28.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Jöcker, Markus
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Martin, Andrew
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Annual performance improvement for solar steam turbines through the use of temperature-maintaining modifications2012In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 86, no 1, 496-504 p.Article in journal (Refereed)
    Abstract [en]

    Steam turbines in solar thermal power plants experience a much greater number of starts than those operating in base-load plants. By maintaining higher internal temperature during idle periods, faster start-up times can be achieved, increasing the flexibility of the plant as well as increasing net electrical production. Prior work by the authors identified a number of methods for achieving this, with strong increases in daily production predicted; only two specific start-up cases were studied however. In order to obtain a more representative evaluation of the performance increase that can be achieved through increased dispatchability of the turbine, the annual improvement needs to be studied. Building on the existing results, a dynamic system model of a parabolic trough power plant has been established and used to determine the distribution of different cool-down times experienced throughout the year, with a view to evaluating the potential annual production increase. A modification of the start-up curves allows an increase in annual electrical production between 6.4% and 2.4% depending upon the operating mode (free operation versus day-time operation). Through application of a combination of heat blankets and an increase in gland steam temperature, further annual production increases between 2.2% and 3.1% are predicted.

  • 29.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Jöcker, Markus
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Martin, Andrew
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermal modeling of a solar steam turbine with a focus on start-up time reduction2012In: Proceedings of the ASME Turbo Expo 2011, Vol 3, 2012, 1021-1030 p.Conference paper (Refereed)
    Abstract [en]

    Steam turbines in solar thermal power plants experience a much greater number of starts than those operating in base-load plants. In order to preserve the lifetime of the turbine whilst still allowing fast starts, it is of great interest to find ways to maintain the turbine temperature during idle periods. A dynamic model of a solar steam turbine has been elaborated, simulating both the heat conduction within the body and the heat exchange with the gland steam, main steam and the environment, allowing prediction of the temperatures within the turbine during off-design operation and standby. The model has been validated against 96h of measured data from the Andasol 1 power plant, giving an average error of 1.2% for key temperature measurements. The validated model was then used to evaluate a number of modifications that can be made to maintain the turbine temperature during idle periods. Heat blankets were shown to be the most effective measure for keeping the turbine casing warm, whereas increasing the gland steam temperature was most effective in maintaining the temperature of the rotor. By applying a combination of these measures the dispatchability of the turbine can be improved significantly: electrical output can be increased by up to 9.5% after a long cool-down and up to 9.8% after a short cool-down.

  • 30.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Jöcker, Markus
    Martin, Andrew
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermal Modeling of a Solar Steam Turbine With a Focus on Start-Up Time Reduction2012In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 134, no 1, 013001- p.Article in journal (Refereed)
    Abstract [en]

    Steam turbines in solar thermal power plants experience a much greater number of starts than those operating in baseload plants. In order to preserve the lifetime of the turbine while still allowing fast starts, it is of great interest to find ways to maintain the turbine temperature during idle periods. A dynamic model of a solar steam turbine has been elaborated, simulating both the heat conduction within the body and the heat exchange with the gland steam, main steam and the environment, allowing prediction of the temperatures within the turbine during off-design operation and standby. The model has been validated against 96 h of measured data from the Andasol 1 power plant, giving an average error of 1.2% for key temperature measurements. The validated model was then used to evaluate a number of modifications that can be made to maintain the turbine temperature during idle periods. Heat blankets were shown to be the most effective measure for keeping the turbine casing warm, whereas increasing the gland steam temperature was most effective in maintaining the temperature of the rotor. By applying a combination of these measures the dispatchability of the turbine can be improved significantly: electrical output can be increased by up to 9.5% after a long cooldown and up to 9.8% after a short cooldown.

  • 31.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermo-economic evaluation of solar thermal and photovoltaic hybridization options for combined-cycle power plants2015In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 137, no 3, 031801- p.Article in journal (Refereed)
    Abstract [en]

    The hybridization of combined-cycle power plants with solar energy is an attractive means of reducing carbon dioxide (CO2) emissions from gas-based power generation. However, the construction of the first generation of commercial hybrid power plants will present the designer with a large number of choices. To assist decision making, a thermo-economic study has been performed for three different hybrid power plant configurations, including both solar thermal and photovoltaic hybridization options. Solar photovoltaic combined-cycle (SPVCC) power plants were shown to be able to integrate up to 63% solar energy on an annual basis, whereas hybrid gas turbine combined-cycle (HGTCC) systems provide the lowest cost of solar electricity, with costs only 2.1% higher than a reference, unmodified combined-cycle power plant. The integrated solar combined-cycle (ISCC) configuration has been shown to be economically unattractive.

  • 32.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A Comparative Thermoeconomic Study of Hybrid Solar Gas-Turbine Power Plants2013In: Proceedings of the ASME Turbo Expo, 2013Conference paper (Refereed)
    Abstract [en]

    The construction of the first generation of commercial hybrid solar gas-turbine power plants will present the designer with a large number of choices. To assist decision making, a thermoeconomic study has been performed for three different power plant configurations, namely simple- and combined- cycles as well as simple-cycle with the addition of thermal energy storage. 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. The solar hybrid combined-cycle plant provides a 60% reduction in electricity cost compared to parabolic trough power plants at annual solar shares up to 20%. The storage integrated designs can achieve much higher solar shares and provide a 7 – 13% reduction in electricity costs at annual solar shares up to 90%. At the same time, the water consumption of the solar gas-turbine systems is significantly lower than conventional steam-cycle based solar power plants.

  • 33.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A Comparative Thermoeconomic Study of Hybrid Solar Gas-Turbine Power Plants2014In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 136, no 1, 011801- p.Article in journal (Refereed)
    Abstract [en]

    The construction of the first generation of commercial hybrid solar gas-turbine power plants will present the designer with a large number of choices. To assist decision making, a thermoeconomic study has been performed for three different power plant configurations, namely, simple-and combined-cycles along with a simple-cycle with the addition of thermal energy storage. 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. The solar hybrid combined-cycle power plant provides a 60% reduction in electricity cost compared to parabolic trough power plants at annual solar shares up to 20%. The storage integrated designs can achieve much higher solar shares and provide a 7-13% reduction in electricity costs at annual solar shares up to 90%. At the same time, the water consumption of the solar gas-turbine systems is significantly lower than conventional steam-cycle based solar power plants.

  • 34.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A Thermoeconomic Study of Low-Temperature Intercooled-Recuperated Cycles for Pure-Solar Gas-Turbine Applications2012In: Journal of solar energy engineering, ISSN 0199-6231, E-ISSN 1528-8986, Vol. 134, no 4, 041015- p.Article in journal (Refereed)
    Abstract [en]

    A dynamic model of a megawatt-scale low-temperature intercooled-recuperated solar gas-turbine power plant has been developed in order to allow determination of the thermodynamic and economic performance. The model was then used for multi-objective thermoeconomic optimization of both the power plant performance and cost, using a population-based algorithm. In order to examine the trade-offs that must be made and identify optimal' plant sizes and operating conditions, two conflicting objectives were considered, namely minimum investment costs and maximum annual electricity production. Levelized electricity costs from a 65 MWe power plant operating at 950°C are predicted to be below 130 USD/MWhe, competitive with other solar thermal power technologies. Optimal plant sizes and configurations have been identified.

  • 35.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Advanced Hybrid Solar Tower Combined-Cycle Power Plants2014In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 49, 1207-1217 p.Article in journal (Refereed)
    Abstract [en]

    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.

  • 36.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Optimal Gas-Turbine Design For Hybrid Solar Power Plant Operation2012In: Proceedings of the ASME Turbo Expo 2012, Vol 6, ASME Press, 2012, 249-259 p.Conference paper (Refereed)
    Abstract [en]

    A dynamic simulation model of a hybrid solar gas-turbine power plant has been developed, allowing determination of its thermodynamic and economic performance. In order to examine optimum gas-turbine designs for hybrid solar power plants, multi-objective thermoeconomic analysis has been performed, with two conflicting objectives: minimum levelized electricity costs and minimum specific CO2 emissions. Optimum cycle conditions: pressure-ratio, receiver temperature, turbine inlet temperature and flow rate, have been identified for a 15 MW, gas-turbine under different degrees of solarization. At moderate solar shares, the hybrid solar gas-turbine concept was shown to provide significant water and CO2 savings with only a minor increase in the levelized electricity cost.

  • 37.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Optimal Gas-Turbine Design for Hybrid Solar Power Plant Operation2012In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 134, no 9Article in journal (Refereed)
    Abstract [en]

    A dynamic simulation model of a hybrid solar gas-turbine power plant has been developed, allowing determination of its thermodynamic and economic performance. In order to examine optimum gas-turbine designs for hybrid solar power plants, multi-objective thermoeconomic analysis has been performed, with two conflicting objectives: minimum levelized electricity costs and minimum specific CO2 emissions. Optimum cycle conditions: pressure-ratio, receiver temperature, turbine inlet temperature and flow rate, have been identified for a 15 MWe gas-turbine under different degrees of solarization. At moderate solar shares, the hybrid solar gas-turbine concept was shown to provide significant water and CO2 savings with only a minor increase in the levelized electricity cost.

  • 38.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Russ, Matthias
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A Thermoeconomic Study of Hybrid Solar Gas-Turbine Power Plants2011In: Proceedings of the International SolarPACES Conference 2011, Granada, 2011Conference paper (Refereed)
    Abstract [en]

    A dynamic simulation model of a hybrid solar gas-turbine power plant has been developed, allowing determination of its thermodynamic and economic performance. Designs were based around two representative gas-turbines: a high efficiency machine and a low temperature machine. In order to examine the trade-offs that must be made, multi-objective thermo-economic analysis was performed, with two conflicting objectives: minimum investment costs and minimum specific CO2 emissions. At current fuel prices, gas-turbine solarisation was shown to result in only a small increase in levelised electricity costs at moderate solar shares. In the future, with higher fuel prices and carbon taxes, it was shown that electricity from hybrid solar gas-turbines could be cheaper than from fossil-only gas-turbines.

  • 39.
    Spelling, James
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Russ, Matthias
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A Thermoeconomic Study of Low-Temperature Intercooled-Recuperated Cycles for Pure-Solar Gas-Turbine Applications2011In: Proceedings of the International SolarPACES Conference 2011, Granada, 2011Conference paper (Refereed)
    Abstract [en]

    A dynamic model of a megawatt-scale low-temperature intercooled-recuperated solar gas-turbine power plant has been developed in order to allow determination of the thermodynamic and economic performance. The model was then used for multi-objective thermo-economic optimisation of both the power plant performance and cost, using a population-based algorithm. In order to examine the trade-offs that must be made and identify ‘optimal’ plant sizes and operating conditions, two conflicting objectives were considered, namely minimum investment costs and maximum annual electricity production. Levelised electricity costs from a 50 – 60 MWe power plant are predicted to be below 150 USD/MWhe, competitive with other solar thermal power technologies, and optimal plant sizes and configurations have been identified.

  • 40.
    Strand, Torsten
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    On the Significance of Concentrated Solar Power R&D in Sweden2011In: Proceedings of the World Renewable Energy Congress 2011, Linköping, 2011Conference paper (Refereed)
    Abstract [en]

    Concentrated Solar Power (CSP) is an emerging renewable energy technology that has the potential to provide a major part of European energy needs at competitive cost levels. Swedish industry is strongly involved in CSP-based energy production either in the form of growing providers on the European energy market or as developers and producers of key components for CSP power plants. The growing industrial interest is reflected and accompanied by state of the art research in this field at the Department of Energy Technology at KTH. In the present paper the main challenges and opportunities for CSP R&D are presented and linked to the industrial environment and interests in Sweden. Related to these challenges, an overview of the latest research activities and results at the Department of Energy Technology is given with examples concerning CSP plant operation and optimisation, techno- economic cycle studies and high temperature solar receiver development.

  • 41.
    Strand, Torsten
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Nilsson, Leif
    Euroturbine AB.
    Hansson, Hans-Erik
    Euroturbine AB.
    An Innovative Hybrid Solar Gas-Turbine Power Plant based on the TopCycle Concept2012In: Proceedings of the International SolarPACES Conference 2012, Marrakesh, 2012Conference paper (Other academic)
    Abstract [en]

    The TopCycle is an innovative gas-turbine power plant, in which a supercharger unit is added to a conventional industrial gas-turbine to boost the pressure ratio, and large amounts of steam are injected into the combustion chamber in order to achieve near- stoichiometric combustion. A thermoeconomic simulation model of a hybrid solar version of such a power plant has been developed, allowing determination of its thermodynamic and economic performance, and the results are compared with a more conventional hybrid solar combined cycle power plant. The analysis has shown that a hybrid solar TopCycle power plant can produce electricity with CO2 emissions below 300 kgCO2/MWhe at levelized costs around 60 – 80 €/MWhe, lower than the competing hybrid combined cycle units, and directly competitive with wind power.

  • 42.
    Topel, Monika
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Genrup, Magnus
    Lund University.
    Jöcker, Markus
    Siemens Industrial Turbomachinery.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Operational Improvements for Start-up Time Reduction in solar Steam Turbines2014In: PROCEEDINGS OF THE ASME TURBO EXPO: Paper No. GT2014-27065 Volume05C, New York: ASME , 2014Conference paper (Refereed)
    Abstract [en]

    Solar steam turbines are subject to high thermal stresses as a result of temperature gradients during transient operation, which occurs more frequently due to the variability of the solar resource. In order to increase the flexibility of the turbines while preserving lifing requirements, several operational modifications for maintaining turbine temperatures during offline periods are proposed and investigated. The modifications were implemented in a dynamic thermal turbine model and the potential improvements were quantified. The modifications studied included: increasing the gland steam pressure injected to the end-seals, increasing the back pressure and increasing the barring speed. These last two take advantage of the ventilation and friction work. The effects of the modifications were studied both individually as well as in different combinations. The temperatures obtained when applying the combined modifications were compared to regular turbine cool-down temperatures and showed significant improvements on the start-up times of the turbine.

  • 43.
    Topel, Monika
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Genrup, Magnus
    Lund University.
    Jöcker, Markus
    Siemens Industrial Turbomachinery.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Operational Improvements for Startup Time Reduction in Solar Steam Turbines2015In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 137, no 4, 042604Article in journal (Refereed)
    Abstract [en]

    Solar steam turbines are subject to high thermal stresses as a result of temperature gradients during transient operation, which occurs more frequently due to the variability of the solar resource. In order to increase the flexibility of the turbines while preserving lifting requirements, several operational modifications for maintaining turbine temperatures during offline periods are proposed and investigated. The modifications were implemented in a dynamic thermal turbine model and the potential improvements were quantified. The modifications studied included: increasing the gland steam pressure injected to the end-seals, increasing the back pressure and increasing the barring speed. These last two take advantage of the ventilation and friction work. The effects of the modifications were studied both individually as well as in different combinations. The temperatures obtained when applying the combined modifications were compared to regular turbine cool-down (CD) temperatures and showed significant improvements on the startup times of the turbine.

  • 44.
    Topel, Monika
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Jöcker, Markus
    Siemens Industrial Turbomachinery.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Geometric Modularity in the Thermal Modeling of Solar Steam Turbines2014In: Proceedings of the SolarPACES 2013 International Conference, Elsevier, 2014, Vol. 49, 1737-1746 p.Conference paper (Refereed)
    Abstract [en]

    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.

1 - 44 of 44
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