Economic Performance of Thermal Energy Storage Integrated With Natural Gas Combined Cycle Power Plants

2015 ◽  
Author(s):  
Barry E. Osterman-Burgess ◽  
D. Yogi Goswami ◽  
Elias K. Stefanakos
Keyword(s):  
Energy Storage ◽  
Natural Gas ◽  
Thermal Energy ◽  
Economic Performance ◽  
Thermal Energy Storage ◽  
Power Plants ◽  
Storage System ◽  
Cost Effective ◽  
Combined Cycle ◽  
Natural Gas Combined Cycle

This paper focuses on the economics of integrating thermal energy storage into natural gas combined cycle power plants for improved operational and economic performance of the utility grid. Costs and fuel consumption are modeled based on a Florida electric utility’s hour-by-hour load data under two scenarios: 1) no storage, and 2) thermal storage attached to intermediate load, NGCC plants, displacing energy production from older, less efficient NGCT peaking units. Due to the nature of the power grid, several of the older units feature abnormally high fuel costs and abnormally low thermal efficiencies. By shifting load from the most expensive peaking units to more cost-effective combined cycles with a 204 MWhth storage system costing about $4 million, savings of more than $1 million per year can be realized while also reducing CO2 emissions by about 5000 metric tons per year. These savings represent an internal rate of returns of up to 23% over a 30-year lifetime, depending on the initial cost of the storage system.

Cost Optimal Strategies of High Temperature Thermal Energy Storage Systems in Combined Heat and Power Applications

2016 ◽  
Author(s):  
Parker Wells ◽  
Karthik Nithyanandam ◽  
Richard Wirz
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Los Angeles ◽  
Natural Gas ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Power Plants ◽  
Combined Heat And Power ◽  
Time Of Day ◽  
Recycled Paper

As variable generation electricity sources, namely wind and solar, increase market penetration, the variability in the value of electricity by time of day has increased dramatically. In response to increase in electricity demand, natural gas “peaker plants” are being added to the grid, and the need for spinning and nonspinning reserves have increased. Many natural gas, and other heat source based, power plants exist as combined heat and power (CHP), or cogeneration, plants. When built for industrial use, these plants are sized and run based on heat needs of an industrial facility, and are not optimized for the value of electricity generated. With the inclusion of new, less expensive thermal energy storage (TES) systems, the heating and electricity usage can be separated and the system can be optimized separately. The use of thermal energy storage with CHP improves system economics by improving efficiency, reducing upfront capital expenditures, and reducing system wear. This paper examines the addition of thermal energy storage to industrial natural gas combined heat and power (CHP) plants. Here a case study is presented for a recycled paper mill near Los Angeles, CA. By implementing thermal energy storage, the mill could decouple electric and heat production. The mill could take advantage of time-of-day pricing while producing the constant heat required for paper processing. This paper focuses on plant economics in 2012 and 2015, and suggests that topping cycle industrial CHP plants could benefit from the addition of high temperature (400–550°C) energy storage. Even without accounting for the California incentives associated with implementing advanced energy storage technologies and distributed generation, the addition of energy storage to CHP plants can drastically reduce the payback period below the 25 year expected economic lifetime of a plant. Thus thermal energy storage can make more CHP plants economically viable to build.

scholarly journals Development and Characterization of Concrete/PCM/Diatomite Composites for Thermal Energy Storage in CSP/CST Applications

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4410
Author(s):  
Adio Miliozzi ◽  
Franco Dominici ◽  
Mauro Candelori ◽  
Elisabetta Veca ◽  
Raffaele Liberatore ◽  
...  
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Power Plants ◽  
Heat Storage ◽  
Low Cost ◽  
Renewable Energy Sources ◽  
Storage System

Thermal energy storage (TES) systems for concentrated solar power plants are essential for the convenience of renewable energy sources in terms of energy dispatchability, economical aspects and their larger use. TES systems based on the use of concrete have been demonstrated to possess good heat exchange characteristics, wide availability of the heat storage medium and low cost. Therefore, the purpose of this work was the development and characterization of a new concrete-based heat storage material containing a concrete mix capable of operating at medium–high temperatures with improved performance. In this work, a small amount of shape-stabilized phase change material (PCM) was included, thus developing a new material capable of storing energy both as sensible and latent heat. This material was therefore characterized thermally and mechanically and showed increased thermal properties such as stored energy density (up to +7%, with a temperature difference of 100 °C at an average operating temperature of 250 °C) when 5 wt% of PCM was added. By taking advantage of these characteristics, particularly the higher energy density, thermal energy storage systems that are more compact and economically feasible can be built to operate within a temperature range of approximately 150–350 °C with a reduction, compared to a concrete-only based thermal energy storage system, of approximately 7% for the required volume and cost.

Design of an Ammonia Synthesis System for Producing Supercritical Steam in the Context of Thermochemical Energy Storage

2015 ◽  
Author(s):  
Chen Chen ◽  
Keith Lovegrove ◽  
H. Pirouz Kavehpour ◽  
Adrienne S. Lavine
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Power Plants ◽  
Ammonia Synthesis ◽  
Storage System ◽  
Homogeneous Model ◽  
Packed Bed ◽  
Reactor Performance ◽  
Synthesis System

Concentrating solar power plants typically incorporate thermal energy storage, e.g. molten salt tanks. The broad category of thermochemical energy storage, in which energy is stored in chemical bonds, has the advantage of higher energy density as compared to sensible energy storage. In the ammonia-based thermal energy storage system, ammonia is dissociated endothermically as it absorbs solar energy during the daytime. The stored energy can be released on demand (for electricity generation) when the supercritical hydrogen and nitrogen react exothermically to synthesize ammonia. Using ammonia as a thermochemical storage system was validated at Australian National University (ANU), but ammonia synthesis has not yet been shown to reach temperatures consistent with the highest performance modern power blocks such as a supercritical steam Rankine cycle requiring steam to be heated to ∼650°C. This paper explores the preliminary design of an ammonia synthesis system that is intended to heat steam from 350°C to 650°C under pressure of 26 MPa. A two-dimensional pseudo-homogeneous model for packed bed reactors previously used at ANU is adopted to simulate the ammonia synthesis reactor. The reaction kinetics are modeled using the Temkin-Pyzhev reaction rate equation. The model is extended by accounting for convection in the steam to predict the behavior of the proposed synthesis reactor. A parametric investigation is performed and the results show that heat transfer plays the predominant role in improving reactor performance.

Modeling of a High-Temperature Latent Heat Thermal Storage Module for Brayton Cycle Applications

2012 ◽  
Author(s):  
Brian Gehring ◽  
Fletcher Miller
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Power Plants ◽  
Relative Concentration ◽  
Storage System ◽  
Time Shift ◽  
Brayton Cycle

Concentrating solar power (CSP) plants with thermal energy storage offer several advantages to plants without storage. Thermal energy storage (TES) allows CSP plants to produce power for longer periods of time each day, making them produce energy more like traditional, fossil fuel power plants. TES also gives the ability to time shift production of energy to times of peak demand, allowing the plant to sell the energy when prices are highest. A CSP plant with storage can increase turbine performance and reach higher levels of efficiency by load leveling production and can remain productive through cloud transients. Power tower CSP plants are capable of producing extremely high temperatures, as they have the ability to oversize their solar field and achieve a greater concentration ratio. Studies have been conducted on variable working fluids, leading to higher working temperatures. This theoretically allows power towers to use more efficient, higher temperature cycles including the recuperated air Brayton cycle, although none currently exist on a commercial scale. This research focuses on developing a model of a high temperature TES system for use with an air Brayton cycle for a power tower CSP plant. In this research we model one module of a latent heat TES system designed to meet the thermal needs of a recuperated Brayton engine of 4.6 MWe capacity for six hours. A metal alloy, aluminum-silicide (AlSi), is considered as the phase change medium. The storage tank is approximately 161 m3, or a cylinder with a 5 m diameter that is 8 m tall filled with AlSi with several air pipes throughout the volume. We model the volume around a single pipe in a 2-D cylindrical coordinate system, for a module size of 0.2 m in diameter and 8 m long. The advantages of using AlSi alloys is that they have variable melting temperatures depending on the relative concentration of the two metals, from 577 C for the eutectic composition of 12.6% silicon to 1411 C for 100% silicon. This attribute is taken advantage of by the TES model as the composition of the AlSi alloy will vary axially. This will allow a cascaded type storage system within one tank and with one material. The use of FLUENT to model this problem is first validated by several analytical solutions including Neumann’s exact solution for a one-dimensional Cartesian geometry and the Quasi-Steady Approximation in a 1-D cylindrical geometry. The model developed will establish charge/discharge times for the storage system, round-trip efficiency of the system, ability of the system to meet the demand of the Brayton cycle, and the validity of using off-eutectic metal alloys in a cascade as a latent heat TES medium.

Survey of Thermal Energy Storage for Parabolic Trough Power Plants

2002 ◽  
Vol 124 (2) ◽  
pp. 145-152 ◽  
Author(s):  
Ulf Herrmann ◽  
David W. Kearney
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Power Plants ◽  
Storage Capacity ◽  
State Of The Art ◽  
Storage System ◽  
Heat Transfer Fluid ◽  
Parabolic Trough ◽  
Tank Storage

A literature review was carried out to critically evaluate the state of the art of thermal energy storage applied to parabolic trough power plants. This survey briefly describes the work done before 1990 followed by a more detailed discussion of later efforts. The most advanced system is a 2-tank-storage system where the heat transfer fluid (HTF) also serves as storage medium. This concept was successfully demonstrated in a commercial trough plant (13.8MWe SEGS I plant; 120MWht storage capacity) and a demonstration tower plant (10MWe Solar Two; 105MWht storage capacity). However, the HTF used in state-of-the-art parabolic trough power plants 30-80MWe is expensive, dramatically increasing the cost of larger HTF storage systems. Other promising storage concepts are under development, such as concrete storage, phase change material storage, and chemical storage. These concepts promise a considerable cost reduction compared to the direct 2-tank system, but some additional R&D is required before those systems can be used in commercial solar power plants. An interesting and likely cost-effective near-term option for thermal energy storage for parabolic trough power plants is the use of an indirect 2-tank-storage, where another (less expensive) liquid medium such as molten salt is utilized rather than the HTF itself.

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