| 1. |
- García, José, et al.
(författare)
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Techno-Economic Optimization of a Combined Cycle Combined Heat and Power Plant With Integrated Heat Pump and Low-Temperature Thermal Energy Storage
- 2020
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Ingår i: Proceedings of the ASME Turbo Expo: Turbomachinery Technical Conference and Exposition, September 21-25, 2020. - : ASME Press.
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Konferensbidrag (refereegranskat)abstract
- The present study presents a techno-economic analysis of a novel power plant layout developed to increase the dispatch flexibility of a Combined Cycle Gas Turbine (CCGT) coupled to a District Heating Network (DHN). The layout includes the incorporation of high temperature heat pumps (HP) and thermal energy storage (TES). A model for optimizing the short-term dispatch strategy of such system has been developed to maximize its operational profit. The constraints and boundary conditions considered in the study include hourly demand and price of electricity and heat, ambient conditions and CO2 emission allowances. To assess the techno-economic benefit of the new layout, a year of operation was simulated for a power plant in Turin, Italy. Furthermore, different layout configurations and critical size-related parameters were considered. Finally, a sensitivity analysis was made to assess the performance under different market scenarios.The results show that it is indeed beneficial, under the assumed market conditions, to integrate a HP in a CCGT plant coupled to a DHN, and that it remains profitable to do so under a variety of market scenarios. The best results for the assumed market conditions were found when integrating a 15 MWth capacity HP in the 400 MWel CCGT-CHP. For this case study, the investment in the HP would yield a net present value (NPV) of 1.22 M€ and an internal rate of return (IRR) of 3.04% for a lifetime of 20 years. An increase was shown also in operational flexibility with 0.14% of the electricity production shifted while meeting the same heating demand. Additionally, it was found that the TES makes the system even more flexible, but does not make up for the extra investment.
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| 2. |
- Guedez, Rafael, et al.
(författare)
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Techno-economic comparative analysis of innovative combined cycle power plant layouts integrated with heat pumps and thermal energy storage
- 2019
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Ingår i: Proceedings of the ASME Turbo Expo. - : ASME Press. - 9780791858608
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Konferensbidrag (refereegranskat)abstract
- In the pursuit of increasing their profitability, the design and operation of combined cycle power plants needs to be optimized for new liberalized markets with large penetration of renewables. A clear consequence of such renewable integration is the need for these plants for being more flexible in terms of ramping-up periods and higher part-load efficiencies. Flexibility becomes an even clearer need for combined heat and power plants to be more competitive, particularly when simultaneously following the market hourly price dynamics and varying demands for both the heat and the electricity markets. In this paper, three new plant layouts have been investigated by integrating different storage concepts and heat-pump units in key sections of a traditional plant layout. The study analyses the influence that market has on determining the optimum layouts for maximizing profits in energy-only markets (in terms of plant configuration, sizing and operation strategies). The study is performed for a given location nearby Turin, Italy, for which hourly electricity and heat prices, as well as meteorological data, have been gathered. A multi parameter modeling approach was followed using KTH's in house teclmo-economic modeling tool, which uses time dependent market data, e.g. price and weather, to determine the trade-off curves between minimizing investment and maximizing profits when varying critical size-related power plant parameters e.g. installed power capacities and storage size, for pre-defined layouts and operating strategies. A comparative analysis between the best configurations found for each of the proposed layouts and the reference plant is presented in the discussion section of the results. For the specific case study set in northern Italy, it is shown that the integration of a pre-cooling loop into baseload-like power-oriented combined cycle plants is not justified, calling for investigating new markets and different operating strategies. Only the integration of a heat pump alone was shown to improve the profitability, but within the margin of error of the study. Alternatively, a layout where district heating supply water is preheated with a combination of a heat pump with hot thermal tank was able to increase the internal rate of return of the plant by up to 0.5%, absolute, yet within the error margin and thus not justifying the added complexity in operation and in investment costs. All in all, the analysis shows that even when considering energy-only market revenue streams (i.e. heat and electricity sells) the integration of heat pump and storage units could increase the profitability of plants by making them more flexible in terms of power output levels and load variations. The latter is shown true even when excluding other flexibilityrelated revenue streams. It is therefore conclusively suggested to further investigate the proposed layouts in markets with larger heat and power price variations, as well as to investigate the impact of additional control logics and dispatch strategies.
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| 3. |
- Mantilla, Weimar, et al.
(författare)
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Short-Term Optimization of a Combined Cycle Power Plant Integrated With an Inlet Conditioning Unit
- 2021
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Ingår i: Journal of engineering for gas turbines and power. - : ASME International. - 0742-4795 .- 1528-8919. ; 143:9
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Tidskriftsartikel (refereegranskat)abstract
- Under new scenarios with high shares of renewable electricity, combined cycle gas turbines (CCGTs) are required to improve their flexibility to help balance the power system. Simultaneously, liberalization of electricity markets and the complexity of its hourly price dynamics are affecting the CCGT profitability, leading the need for optimizing its operation. An inlet conditioning unit (ICU) offers the benefit of power augmentation and “minimum environmental load” (MEL) reduction by controlling the gas turbine (GT) inlet temperature using cold thermal energy storage (TES) and a heat pump (HP). Consequently, an evaluation of a CCGT integrated with this unit including a day-ahead optimized operation strategy was developed in this study. To establish the hourly dispatch of the power plant and the operation mode of the ICU, a mixed-integer linear programing (MILP) optimization was formulated, aiming to maximize the operational profit of the plant within a 24 h horizon. To assess the impact of the unit operating under this dispatch strategy, historical data have been used to perform annual simulations of a reference power plant located in Turin, Italy. Results indicate that the power plant's operational profit increases by achieving a wider operational range during peak and off-peak periods. For the specific case study, it is estimated that the net present value (NPV) of the CCGT integrated with the ICU is 0.5% higher than the CCGT without it. Results also show that the unit reduces the MEL by approximately 1.34% and can increase the net power output by 0.17% annually.
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| 4. |
- Sorce, Alessandro, et al.
(författare)
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Analysis of a combined cycle exploiting inlet conditioning technologies for power modulation
- 2019
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Ingår i: Proceedings of the ASME Turbo Expo. - : ASME Press. - 9780791858608
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Konferensbidrag (refereegranskat)abstract
- The high share of non-dispatchable renewable energy source generators in the electrical grid has increased the need for flexibility of Gas Turbine Combined Cycles (GTCC) already installed. To maximize not only the maximum power produced, via Power Augmentation Technologies (PATs), but also to reduce the Minimum Environmental Load (MEL), both OEMs and GTCC owners have adopted several technical solutions. This kind of flexibility has become, year-by-year, ever more crucial to guarantee GTCC economical sustainability. Amongst the solutions which can be adapted to guarantee GTCC flexibility, the Inlet Conditioning System is a particularly interesting technical solution, which can be installed without restrictions related to the different GT design. In this paper, an evaluation of the compressor inlet temperature effect over the Combined Cycle performance is presented, with a focus on the bottoming Cycle impact. Different Inlet Conditioning Strategies are then compared considering the energy, and the environmental impact on GTCC behavior. The performance of a layout including a Thermal Energy Storage (TES) and a Heat Pump (HP) is then evaluated and compared to other technical solutions.
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| 5. |
- Vannoni, Alberto, et al.
(författare)
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Ancillary Services Potential For Flexible Combined Cycles
- 2021
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Ingår i: Proceedings of the ASME Turbo Expo, American Society of Mechanical Engineers (ASME) , 2021. - USA : American Society of Mechanical Engineers.
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Konferensbidrag (refereegranskat)abstract
- Combined Cycle Gas Turbines, CCGTs, are oftenconsidered as the bridging technology to a decarbonized energysystem thanks to their high exploitation rate of the fuel energeticpotential. At present time in most European countries, however,revenues from the electricity market on their own are insufficientto operate existing CCGTs profitably, also discouraging newinvestments and compromising the future of the technology. Inaddition to their high efficiency, CCGTs offer ancillary servicesin support of the operation of the grid such as spinning reserveand frequency control, thus any potential risk of plantdecommissioning or reduced investments could translate into arisk for the well-functioning of the network. To ensure thereliability of the electricity system in a transition towards ahigher share of renewables, the economic sustainability ofCCGTs must be preserved, for which it becomes relevant tomonetize properly the ancillary services provided. In this paper,an accurate statistical analysis was performed on the day-ahead,intra-day, ancillary service, and balancing markets for the wholeItalian power-oriented CCGT fleet. The profitability of 45 realproduction units, spread among 6 market zones, was assessed onan hourly basis considering local temperature, specific plantlayouts, and off-design performance. The assessment revealedthat net income from the ancillary service market doubled, onaverage, the one from the day-ahead energy market. It wasobserved that to be competitive in the ancillary services marketCCGTs are required to be more flexible in terms of ramp rates,minimum environmental loads, and partial load efficiencies.This paper explores how integrating a Heat Pump and a ThermalEnergy Storage within a CCGT could allow improving itscompetitiveness in the ancillary services market, and thus itsprofitability, by means of implementing a model of optimaldispatch operating on the ancillary services market
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| 6. |
- Vannoni, Alberto, et al.
(författare)
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Combined Cycle, Heat Pump, and Thermal Storage Integration : Techno-Economic Sensitivity to Market and Climatic Conditions Based on a European and United States Assessment
- 2023
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Ingår i: Journal of engineering for gas turbines and power. - : American Society of Mechanical Engineers (ASME). - 0742-4795 .- 1528-8919. ; 145:2
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Tidskriftsartikel (refereegranskat)abstract
- The integration of a heat pump (HP) with a combined cycle gas turbine (CCGT) to control the inlet air temperature is a promising technology to meet the requirements imposed by the current electricity systems in terms of efficiency and flexibility. If the HP is coupled with a thermal energy storage (TES) in an inlet conditioning unit (ICU), it can be exploited in different modes to enhance the off-design CCGT's efficiency or to boost the power output at full load. Furthermore, fuel-saving would be reflected in avoided emissions. The optimal sizing of the ICU, as well as an accurate estimation of the benefits, is a complex problem influenced by several factors such as the local climate and electricity market prices. This paper aims to systematically investigate, utilizing a mixed integer linear programming (MILP) model for optimal dispatch, the feasibility of an ICU integration in different scenarios (EU and US). Different electricity markets have been analyzed and classified according to the parameters describing the average and variability of prices, the interdependency with the gas market, the ambient temperature, or the local carbon pricing policy. The most favorable conditions are identified and the dependency of the optimal ICU sizing on the climate and the electricity market is highlighted. This paper provides information for a first viability assessment: the concept appears to be highly profitable in hot regions with high price variability. Additionally, even in less profitable conditions (i.e., stable low prices in a cold climate), the system increases operating hours and reduces economic losses.
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| 7. |
- Zaccaria, Valentina, 1989-, et al.
(författare)
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Influence of multiple degrading components on fuel cell gas turbine hybrid systems lifetime
- 2018
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Ingår i: Proceedings of GPPS Forum 18 Global Power and Propulsion Society Zurich, 10th-12th January 2018.
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Konferensbidrag (refereegranskat)abstract
- Energy system reliability and operational cost depend highly on the performance degradation experienced by system components. In complex systems, degradation of each single component affects matching and interactions of different system parts. Gas turbine fuel cell hybrid systems combine two different technologies to produce power with an extremely high conversion efficiency. Severe performance decay over time currently limits high temperature fuel cells lifetime; although at a different rate, gas turbine engines also experience gradual deterioration phenomena such as erosion, corrosion, and creep. This work aims at evaluating, for the first time, the complex performance interaction between degrading components in a hybrid system. The effect of deterioration in gas turbine pressure ratio and efficiency on fuel cell performance was analyzed, and at the same time, the impact of the degrading fuel cell thermal output on turbine blade aging was modeled to estimate a remaining useful lifetime.
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