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A Techno-Economic Framework for the Analysis of Concentrating Solar Power Plants with Storage
KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. (Concentrating Solar Power Group)
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Concentrating solar power plants can integrate cost-effective thermal energy storage systems and thereby supply controllable power on demand, an advantage against other renewable technologies. Storage integration allows a solar thermal power plant to increase its load factor and to shift production to periods of peak demand. It also enables output firmness, providing stability to the power block and to the grid. Thus, despite the additional investment, storage can enhance the performance and economic viability of the plants.

However, the levelized cost of electricity of these plants yet remains higher than for other technologies, so projects today are only viable through the provision of incentives or technology-specific competitive bid tenders. It is the variability of the solar resource, the myriad roles that storage can assume, and the complexity of enhancing the synergies between the solar field, the storage and the power block, what makes the development of adequate policy instruments, design and operation of these plants a challenging process.

In this thesis a comprehensive methodology for the pre-design and analysis of concentrating solar power plants is presented. The methodology is based on a techno-economic modeling approach that allows identifying optimum trade-off curves between technical, environmental, and financial performance indicators. A number of contemporary plant layouts and novel storage and hybridization concepts are assessed to identify optimum plant configurations, in terms of component size and storage dispatch strategies.

Conclusions highlight the relevance between the sizing of key plant components, the operation strategy and the boundaries set by the location. The interrelation between critical performance indicators, and their use as decisive parameters, is also discussed. Results are used as a basis to provide recommendations aimed to support the decision making process of key actors along the project development value chain of the plants. This research work and conclusions are primarily meant to set a stepping stone in the research of concentrating solar power plant design and optimization, but also to support the research towards understanding the value of storage in concentrating solar power plants and in the grid.

Abstract [sv]

Koncentrerad solkraft erbjuder möjligheten att integrera kostnadseffektiv termisk energilagring och därmed behovsstyrd kraftkontroll. Detta är en viktig fördel jämfört med andra förnybara energiteknologier. Lagringsintegration tillåter solkraftsanläggningar att öka sin lastfaktor och skifta produktion till tider med största efterfrågan. Vidare möjliggör lagring fast elproduktion vilket leder till förbättrad nät- och kraftturbinstabilitet. Därför kan termisk lagring öka anläggningsprestanda och ekonomiskt värde trots ökande initiala kapitalkostnader.

I termer av specifik elproduktionskostnad (LCOE) ligger koncentrerade solkraftsanläggningar med lagring fortfarande högre än andra kraftteknologier och anläggningsprojekt blir endast lönsamma genom subventionsmodeller eller teknologispecifika konkurrensutsatta anbudsförfaranden. Att hitta adekvata policylösningar och optimala design och operationsstrategier är en utmanande process eftersom det gäller att hitta rätt balans mellan variabel solinstrålning, lagring av energi och tid för produktion genom optimal design och operation av solmottagarfält, kraftblock och lagringskapacitet.

I denna avhandling presenteras en omfattande metodik för pre-design och analys av koncentrerande solkraftverk. Metodiken baseras på en tekno-ekonomisk modelleringsansats som möjliggör identifiering av optimala avvägningssamband för tekniska, ekonomiska och miljöprestanda indikatorer. Metodiken tillämpas på ett antal moderna anläggningslayouter  och lagrings- och hybridiseringskoncept för att identifiera optimal kraftanläggningsdesign i termer av komponentprestanda och lagringsanvändningsstrategier. I slutsatsen poängteras relevansen av att hitta rätt storlek på nyckelkomponenter i relation till lagringsstrategi och randvillkoren som ges av konstruktionsläget för optimal ekonomisk och miljömässig prestanda. Resultaten används för att formulera rekommendationer till nyckelaktörer i beslutsprocessen genom hela kraftanläggningens värdekedja från politisk beslutsfattare till anläggningsingenjör. Forskningen och slutsatserna i detta arbete skall i första hand ta ett steg framåt för optimering och design av solkraftsanläggningar men även tillhandahålla en metodik för utvärdering av lagringslösningar och dess specifika värde för solkraftsanläggningar och elnätet.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2016. , 239 p.
Series
TRITA-KRV, ISSN 1100-7990 ; 2016:01
Keyword [en]
Concentrating solar power, thermal energy storage, techno-economic analysis
Keyword [sv]
Termisk solkraft, termisk energilagring, techno-eknomiska analys
National Category
Energy Engineering
Research subject
Energy Technology
Identifiers
URN: urn:nbn:se:kth:diva-191339ISBN: 978-91-7729-086-5OAI: oai:DiVA.org:kth-191339DiVA: diva2:956167
Public defence
2016-09-23, M2, Brinellvägen 64, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20160829

Available from: 2016-08-29 Created: 2016-08-29 Last updated: 2016-08-30Bibliographically approved
List of papers
1. Enhancing the profitability of solar tower power plants through thermoeconomic analysis based on multi-objective optimization
Open this publication in new window or tab >>Enhancing the profitability of solar tower power plants through thermoeconomic analysis based on multi-objective optimization
2015 (English)In: INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014, 2015, Vol. 69, 1277-1286 p.Conference paper (Refereed)
Abstract [en]

Solar tower power plants with integrated thermal energy storage units represent one of the most promising technologies for enhancing the economic viability of concentrating solar power in the short term. Tower systems allow higher concentration ratios to be achieved, which in turn means higher fluid operating temperatures and thus higher power cycle efficiencies. Moreover, the integration of storage allows power production to be shifted from times where there is low demand to periods where electricity prices are higher, potentially enhancing the profitability of the plant despite representing an additional upfront cost. The variable nature of the solar resource and the myriad potential roles that storage can assume, together with the complexity of enhancing the synergies between the three blocks: the solar field, the storage block and power block, make the design of these power plants a challenging process. This paper introduces a comprehensive methodology for designing solar tower power plants based on a thermoeconomic approach that allows the true optimum trade-off curves between cost, profitability and investment to be identified while simultaneously considering several operating strategies as well as varying critical design parameters in each of the aforementioned blocks. The methodology is presented by means of analyzing the design of a power plant for the region of Seville. For this location, results show that similar profits, measured in terms of the internal rate of return, can be achieved from different power plant configurations in terms of sizing and operating strategy, each associated to different investments. In particular, optimum configurations found corresponded to larger power blocks with medium-to-large solar field and storage blocks that allow the plants to operate continuously throughout the day and be shut down during midnight. Moreover, it is shown that for a fixed power block size it can also be economically interesting to consider smaller storage units and adopt instead a peaking strategy, as this can still be profitable whilst representing a lower investment, thus lower risk.

Series
, Energy Procedia, ISSN 1876-6102
Keyword
multi-objective optimization, concentrating solar power, techno-economic analysis, thermal energy storage
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-173188 (URN)10.1016/j.egypro.2015.03.155 (DOI)000358735000135 ()2-s2.0-84943652120 (ScopusID)
Conference
International Conference on Concentrating Solar Power and Chemical Energy Systems (SolarPACES), SEP 16-19, 2014, Beijing, PEOPLES R CHINA
Note

QC 20150911

Available from: 2015-09-11 Created: 2015-09-07 Last updated: 2016-08-29Bibliographically approved
2. A Methodology for Determining Optimum Solar Tower Plant Configurations and Operating Strategies to Maximize Profits Based on Hourly Electricity Market Prices and Tariffs
Open this publication in new window or tab >>A Methodology for Determining Optimum Solar Tower Plant Configurations and Operating Strategies to Maximize Profits Based on Hourly Electricity Market Prices and Tariffs
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2016 (English)In: ASME Journal of Solar Energy Engineering, Vol. 138, no 2, 021006Article in journal (Refereed) Published
Abstract [en]

The present study analyzes the influence that market conditions have on determining optimum molten salt solar tower plants with storage that maximizes profits (in terms of plant configuration, sizing, and operation) for a location in South Africa. Three different scenarios based on incentive programs and local wholesale electricity prices are considered. A multi-objective optimization modeling approach was followed, showing the tradeoff curves between minimizing investment and maximizing profits when varying critical size-related parameters (such as nameplate capacity, solar multiple (SM), and storage capacity) together with power-cycle design and operating specifications including dynamic startup curves and different storage dispatchability strategies. Results are shown by means of a comparative analysis between optimal plants found for each scenario, highlighting the value that storage has under the current two-tier tariff scheme and the relevance of designing a suitable policy for technology development. Finally, a final analysis is performed with regard to the indicators used for economic evaluation of power plants, by comparing the differences between optimum designs found when using the levelized cost of electricity (LCoE) solely as performance indicator instead of cash-flows and profit-based indicators, such as the internal rate of return (IRR).

Place, publisher, year, edition, pages
ASME Press, 2016
National Category
Energy Engineering
Research subject
Energy Technology
Identifiers
urn:nbn:se:kth:diva-182120 (URN)10.1115/1.4032244 (DOI)000372736200006 ()2-s2.0-84956610420 (ScopusID)
Note

QC 20160216

Available from: 2016-02-16 Created: 2016-02-16 Last updated: 2016-08-29Bibliographically approved
3. Techno-economic Performance Evaluation of Solar Tower Plants with Integrated Multi-layered PCM Thermocline Thermal Energy Storage - A Comparative Study to Conventional Two-tank Storage Systems
Open this publication in new window or tab >>Techno-economic Performance Evaluation of Solar Tower Plants with Integrated Multi-layered PCM Thermocline Thermal Energy Storage - A Comparative Study to Conventional Two-tank Storage Systems
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2016 (English)In: SOLARPACES 2015: INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, 2016, UNSP 070012Conference paper (Refereed)
Abstract [en]

Solar Tower Power Plants with thermal energy storage are a promising technology for dispatchable renewable energy in the near future. Storage integration makes possible to shift the electricity production to more profitable peak hours. Usually two tanks are used to store cold and hot fluids, but this means both higher investment costs and difficulties during the operation of the variable volume tanks. Instead, another solution can be a single tank thermocline storage in a multi-layered configuration. In such tank both latent and sensible fillers are employed to decrease the related cost up to 30% and maintain high efficiencies. This paper analyses a multi-layered solid PCM storage tank concept for solar tower applications, and describes a comprehensive methodology to determine under which market structures such devices can outperform the more conventional two tank storage systems. A detail model of the tank has been developed and introduced in an existing techno-economic tool developed by the authors (DYESOPT). The results show that under current cost estimates and technical limitations the multi-layered solid PCM storage concept is a better solution when peaking operating strategies are desired, as it is the case for the two-tier South African tariff scheme.

Series
, AIP Conference Proceedings, ISSN 0094-243X ; 1734
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-191040 (URN)10.1063/1.4949159 (DOI)000380374600134 ()978-0-7354-1386-3 (ISBN)
External cooperation:
Conference
21st International Conference on Concentrating Solar Power and Chemical Energy Systems (SolarPACES), OCT 13-16, 2015, Cape Town, SOUTH AFRICA
Note

QC 20160825

Available from: 2016-08-25 Created: 2016-08-23 Last updated: 2016-08-29Bibliographically approved
4. Enhancing the Economic Competitiveness of Concentrating Solar Power Plants through an Innovative Integrated Solar Combined-Cycle with Thermal Energy Storage
Open this publication in new window or tab >>Enhancing the Economic Competitiveness of Concentrating Solar Power Plants through an Innovative Integrated Solar Combined-Cycle with Thermal Energy Storage
2014 (English)In: 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.

National Category
Energy Engineering
Research subject
Energy Technology
Identifiers
urn:nbn:se:kth:diva-148157 (URN)10.1115/GT2014-26098 (DOI)000362057900041 ()2-s2.0-84961310706 (ScopusID)978-0-7918-4565-3 (ISBN)
Conference
ASME Turbo Expo 2014, Turbine Technical Conference and Exposition, GT 2014; Dusseldorf, Germany, 16-20 June 2014
Note

QC 20150305

Available from: 2014-08-01 Created: 2014-08-01 Last updated: 2016-08-29Bibliographically approved
5. A Techno-Economic Analysis Of Hybrid Concentrating Solar Power And Solar Photovoltaic Power Plants For Firm Power In Morocco
Open this publication in new window or tab >>A Techno-Economic Analysis Of Hybrid Concentrating Solar Power And Solar Photovoltaic Power Plants For Firm Power In Morocco
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2016 (English)In: Journal of solar energy engineering, ISSN 0199-6231, E-ISSN 1528-8986Article in journal (Refereed) Submitted
Abstract [en]

The present study evaluates the optimum configurations and operating strategies of hybrid concentrating solar power and solar photovoltaic power plants for minimizing levelized costs of electricity. These configurations were also required to meet specific design objectives as provided by competitive bid tenders, such as power plant size and operating hours, for a suitable location near Midelt, Morocco. A detailed techno-economic model of the hybrid plant was developed at KTH’s in-house optimization tool DYESOPT, which allows power plant evaluation by means of technical and economic performance indicators. Results show that hybrid plants are able to achieve higher capacity factors. It is also confirmed that, under current cost estimates, hybridization enables a lower cost solution for a given high capacity factor objective than what is achievable either with stand-alone concentrating solar power or solar photovoltaic power plants, respectively. The analysis highlights synergies among the technologies and shows the relation and influence between sizing and operation of their critical components. Main challenges for successful hybridization are also raised together with recommendations for addressing them. Lastly, optimum configurations found for different tender conditions are compared and a brief discussion section at the end is introduced to highlight the relevance of adequate policy design and its impact on the work of project developers for proposing the most competitive solutions

Place, publisher, year, edition, pages
ASME Press, 2016
Keyword
Hybrid CSP-PV, Concentrating solar power, CSP, Photovoltaic, PV, Techno-economic Analysis
National Category
Energy Engineering
Research subject
Energy Technology
Identifiers
urn:nbn:se:kth:diva-191340 (URN)
External cooperation:
Note

QC 20160829

Available from: 2016-08-29 Created: 2016-08-29 Last updated: 2016-08-29Bibliographically approved
6. Thermoeconomic Optimization of Solar Thermal Power Plants with Storage in High-Penetration Renewable Electricity Markets
Open this publication in new window or tab >>Thermoeconomic Optimization of Solar Thermal Power Plants with Storage in High-Penetration Renewable Electricity Markets
2013 (English)In: 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.

Series
, Energy Procedia, ISSN 1876-6102
Keyword
Solar Thermal Power, Concentrating Solar Power, Thermal Energy Storage, Electricity Demand, Renewable Energy
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-126929 (URN)10.1016/j.egypro.2014.10.208 (DOI)000348253200059 ()2-s2.0-84922279172 (ScopusID)
Conference
2013 ISES Solar World Congress, SWC 2013; Cancun; Mexico; 3 November 2013 through 7 November 2013
Note

QC 20150326

Available from: 2013-08-22 Created: 2013-08-22 Last updated: 2016-08-29Bibliographically approved
7. Reducing the Number of Turbine Starts in Concentrating Solar Power Plants through the Integration of Thermal Energy Storage
Open this publication in new window or tab >>Reducing the Number of Turbine Starts in Concentrating Solar Power Plants through the Integration of Thermal Energy Storage
2015 (English)In: Journal of solar energy engineering, ISSN 0199-6231, Vol. 137, no 2Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
ASME Press, 2015
National Category
Energy Engineering
Research subject
Energy Technology
Identifiers
urn:nbn:se:kth:diva-148156 (URN)10.1115/1.4028004 (DOI)000348145600003 ()2-s2.0-84904977331 (ScopusID)
Note

Qc 20140925

Available from: 2014-08-01 Created: 2014-08-01 Last updated: 2016-08-29Bibliographically approved

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