Molten Salt Thermal Energy Storage Research Articles

Performance analysis of integrated Nuclear-Solar Energy system sharing same molten salt thermal energy storage

Advanced nuclear reactors may be deployed with integrated thermal energy storage to improve flexibility and maximize revenue. This presents opportunities for thermal integration with concentrating solar power (CSP) to generate component synergies and/or improve performance. In this study, a computational model is developed for an integrated nuclear and CSP system that both share the same molten salt thermal energy storage (TES). Optimized dispatch schedules are developed subject to various market conditions, and the ratio of the nuclear to CSP thermal output is also varied. Performance of the combined system is compared to separate nuclear and solar plants, to determine if there is an overall benefit that can be derived from sharing the TES. Given sufficient volatility in electricity prices (e.g., under CAISO market conditions), synergies of up to 8% in net revenue are observed as a result of sharing the same TES, primarily due to improved revenue from enabling operation of the turbine closer to its design point, as well as being able to better take advantage of higher electricity prices. The synergy benefits are largest when the nuclear and solar plants have similar thermal output. However, when prices are less volatile the opposite behavior can be observed and it can be preferable to operate the nuclear plant as a baseload generator.

Dynamic characteristics and economic analysis of a coal-fired power plant integrated with molten salt thermal energy storage for improving peaking capacity

Improving the peaking capacity of coal-fired units is imperative to ensure the stability of the power grid, thus facilitating the grid integration and popularization of large-scale renewable energy. To address this issue, this paper introduces a new concept that combines molten salt energy storage with coal-fired power plants. The proposed design consists of extracting a portion of steam from the turbine side and adjusting the extracted steam mass flow rate by adjusting the valve opening to improve the dynamic characteristics of a coal-fired power plant in terms of both increasing the peaking depth and peaking speed. A coal-fired boiler with integrated thermal energy storage was dynamically modeled using Dymola and its accuracy was verified. The results show that the highest equivalent round-trip efficiency is achieved by extracting from the main steam and discharging into the feedwater during charging process and from reheater1 and discharging into the feedwater during discharging process; The peaking potential during charging and discharging is 12.83 % Pe and 6.86 % Pe respectively, with maximum peaking rates of 9.27 % Pe/min and 5.11 % Pe/min respectively, and the optimal peaking method is also proposed according to the different peaking situations. The total cost of equipment and materials to retrofit the conventional coal-fired units was 19,948,193 USD and the levelized cost of delivery was 151.29 USD/MWh.

Thermoeconomic analysis and multiple parameter optimization of a combined heat and power plant based on molten salt heat storage

The global energy supply is transitioning to sustainable, low-carbon energy. Power-to-heat technology with molten salt thermal energy storage (TES) is a potential way to accommodate renewable power, and the stored heat can be converted to heat and electricity for residential heating and power supply with a combined heat and power plant (CHP). In this study, a CHP-TES system with valley electricity as the input energy source is proposed. Thermodynamic models are developed, and an economic evaluation index is established by considering electricity price, heat price, TES scale, and CHP layout. Then, multiparameter optimization of the proposed CHP-TES system is conducted with the genetic algorithm, and the energy-exergy-economic feasibilities of the system are evaluated. The CHP-TES system can operate under CHP and condensing modes in heating and non-heating periods, and its output power can be regulated during peak and valley load time, respectively. The exergy efficiency of the CHP-TES system is 45.07% and 36.67% in condensing modes with the peak and valley output power, respectively. The exergy efficiency of the CHP-TES system is 46.16% and 42.96% in CHP modes with the peak and valley output power, respectively. The exergy is mainly destructed in the electric heater, which accounts for over 65% of the total exergy loss in all operation modes. The equipment investment of the TES, steam generator, and CHP systems account for 87.59%, 3.53%, and 8.88% of the total, respectively. The electric heater takes the largest portion of the total equipment investment, which accounts for 37.99%. When the peak-valley electricity price changes from 0.121 $ kWh−1 to 0.259 $ kWh−1, the net present value increases from $592 million to $5.79 billion.

A ranking methodology for the coupling of pressurized water nuclear reactors and molten salt thermal energy storage

Thermal energy storage (TES) systems are a proposed solution to electricity market demand fluctuations and can be coupled to nuclear power plants to enable load following. This work focuses on developing a methodology for evaluating potential designs for integrating a TES system into an existing pressurized water nuclear power plant. The proposed ranking methodology allows a group of experts to postulate and weigh designs based on ranking criteria derived from literature. The methodology developed in this study can aid in the final selection of a TES design for an existing nuclear power plant. The same process could be used to analyze other TES and nuclear reactor designs. The determined optimum design from this methodology was to place the TES system after the steam generator and to utilize the steam generated from the nuclear power plant to heat a molten salt TES unit. Another conclusion of this research was that human bias is prevalent during design selection, and actions such as standardized ranking criteria and large groups of experts should be used to minimize this error.

CONCENTRATING SOLAR POWERED TRANSCRITICAL CO2 POWER GENERATION CYCLE FOR THE UNION TERRITORY OF LADAKH, INDIA

High solar irradiation, cloud-free dry climate, abundant barren land, and low ambient temperature make the Union Territory of Ladakh, India, suitable for concentrating solar thermal power (CSP) plants. The present study comprehensively analyzes a 5 MW transcritical CO<sub>2</sub> Rankine cycle power tower CSP plant. Low ambient temperature of the region allows transcritical operation, which provides high cycle efficiency. The study focuses on five aspects: solar field and thermal energy storage (TES), thermodynamic cycle simulation, turbomachines, and off-design performance analysis. Modeling and optimization of the solar field are undertaken to capture the diurnal and annual variations of direct normal irradiation levels using System Advisor Model open source software. Molten salt TES is integrated to overcome the dynamic variations of solar energy by providing stable operations and additional hours. The effect of storage sizes, starting from no storage to 12 hours, on the solar field size and specifications is also assessed. An in-house algorithm is developed for thermodynamic cycle optimization, exergy analysis, and off-design operations. The turbomachines of the cycle are designed using in-house meanline codes, and 3D CFD simulations are conducted for efficiency estimations. The effects of ambient temperature variations on the low side saturation pressure, cycle efficiency, and power output are evaluated. The proposed plant offers annual optical efficiency of 54.1%, thermal efficiency of 36.5%, and overall efficiency of 19.7%.

Study of combined heat and power plant integration with thermal energy storage for operational flexibility

Increasing the share of renewable energy in the future electricity market requires measures to maintain the stability of the grid, owing to the volatility and intermittency of renewable energy. For a combined heat and power (CHP) plant, molten salt thermal energy storage (TES) can be added to improve the flexibility to meet the needs of peak shaving. This paper proposed a novel cascade reheat steam extraction system to adjust the electrical load by using EBSILON software applied to thermal simulation and thermal analysis. A 350 MW supercritical CHP plant was used as an example to analyze the thermal and peak shaving performance under variable operating conditions. Meanwhile, through the static simulation, the change in the load and the efficiency of TES can be calculated during the charging and discharging cycle. The results show that the efficiency of TES is 40–51 %. With an increase in the load, the efficiency of TES is reduced, and the exergy loss range is from 4 MW to 12.4 MW mainly due to the throttling process and the molten salt heat transfer process. Moreover, the thermal efficiency and exergy efficiency of the novel system are higher than those of the traditional CHP plant below 60 % turbine heat acceptance, so it is relatively economical to run for peak shaving under low loads. Finally, depending on the corresponding operating strategy, a reduction of the minimum load by up to 1 % of the rated output electrical load during charging and an increase of the maximum load by up to 2 % of the rated output electrical load during discharging are possible. Overall, the proposed system provides a feasible method for the flexibilization of CHP plants alongside new renewable systems.

Retrofitting coal-fired power plants for grid energy storage by coupling with thermal energy storage

• Thermal storage is coupled with coal-fired power plant for grid energy storage. • The coupled plant has higher efficiency than the original one at low load. • Investment is greatly reduced using existing facilities of coal-fired power plant. • Levelized cost of electricity shows advantage with storage period less than 10 h. Grid energy storage is key to the development of renewable energies for addressing the global warming challenge. Although coal-fired power plant has been coupled with thermal energy storage to enhance their operational flexibility, studies on retrofitting coal-fired power plants for grid energy storage is lacking. In this work, molten salt thermal energy storage is integrated with supercritical coal-fired power plant by replacing the boiler. Electric resistive heating is applied for the charging process using curtailed electricity or during periods with low grid demand. During discharging, the heat stored in the molten salt is exchanged to steam for electricity generation. A techno-economical analysis is performed on the coupled system and compared with other grid energy storage technologies. Results show that the integrated plant has higher thermal efficiency than the original coal-fired power plant, especially at low load for peak shaving purpose, which is due to the less exergy loss by avoiding the exhausted flue gas and the large temperature difference of heat transfer in boiler of the original plant. At full load, the round-trip efficiency of the integrated plant is ∼ 41.8 %. Although this efficiency is lower than other energy storage technologies, the levelized cost of electricity of the integrated plant is generally lower due to the reduction in initial investment utilizing existing infrastructures of coal-fired power plants. With longer discharging duration (≥10 h), the integrated system shows a similar levelized cost of electricity as that of compressed air energy storage. Replacing the boiler with thermal energy storage would also greatly reduce the CO 2 emission and various pollutants from coal combustion.

Repowering a Coal Power Unit with Small Modular Reactors and Thermal Energy Storage

In the first months of 2022, there was a sharp turn in the energy policy of the European Union, initially spurred by increasing energy prices and further escalated by Russia’s invasion of the Ukraine. Further transformation of the energy system will likely be accompanied by the gradual abandonment of natural gas from Russia and an increase of renewable and nuclear energy. Such a transition will not only increase energy security, but also accelerate the pace at which greenhouse gas emissions are reduced in Europe. This could be achieved more effectively if some of the new nuclear energy capacity is optimized to play an increased balancing role in the energy system, thus allowing for deeper market penetration of intermittent renewable energy sources with a reduced need for flexible fossil backup power and storage. A double effect of decarbonization can be achieved by investments in nuclear repowering of coal-fired units, with the replacement of coal boiler islands with nuclear reactor systems. Repowered plants, in turn, operate flexibly via integration with thermal energy storage systems using molten salt. This paper presents the results of a technoeconomic analysis for three cases of nuclear repowering of a 460 MW supercritical coal-fired unit in Poland. The first reference case assumes that three reactors are replacing the existing coal boilers, while the second reference leverages two reactors. The third uses two nuclear reactors equipped with a molten salt thermal energy storage system as a buffer for the heat produced by the reactor system. The analysis of the third case demonstrates how the TES system’s capacity varies from 200 to 1200 MWh, highlighting the possibility of obtaining a high degree of flexibility of the nuclear unit due to TES system without significant drops in the efficiency of electricity production. The economic analysis demonstrates that integration with TES systems may be beneficial if the current levels of daily variation in electricity prices are maintained. For current market conditions, the most attractive investment is a case with two reactors and a TES system capacity of 800 MWh; however, with the increasing price volatility, this grows to a larger capacity of 1000 or 1200 MWh.

A hybrid concentrated solar/biomass combustion system with internal thermal energy storage for fully dispatchable renewable electricity production in Mauritius

AbstractWind and solar photovoltaic need expensive battery energy storage for dispatchability. Concentrated solar power plus internal thermal energy storage permits dispatchability, but it is convenient only in areas of large direct normal irradiance. A hybrid concentrated solar/combustion system is proposed for Mauritius, an area of modest direct normal irradiance, and biomass availability. The small, modular, 8 kW system for microgrid application comprises a beam down point concentrator, two tanks of molten salt thermal energy storage, a biomass combustion heater, a Stirling engine, and a generator. The hybrid system has a thermal energy supply solar of 41%, and a thermal energy supply by combustion fuel 59%. By assuming a zero CO2e emission for solar thermal energy supply (100% reduction of CO2e) and a 21% CO2e emission for thermal energy from the combustion of bagasse (79% reduction) vs thermal energy from oil combustion, the proposed hybrid device would permit an 88% reduction of the emission of CO2 vs the reference oil combustion plant.

The multi-stage framework for optimal sizing and operation of hybrid electrical-thermal energy storage system

In order to mitigate the intermittency of renewable energy, the paper proposes a hybrid electrical-thermal energy storage system, which complementarily utilizes the cost-effective two-tank direct molten salt thermal energy storage system and the flexible lead-acid battery. A multi-stage framework is further proposed for optimal sizing and operation of the hybrid energy storage system. First, the renewable energy capacity is optimized considering the minimization of total net load. Then, the typical net load profiles are selected by K-means clustering algorithm. Finally, a bi-level optimization model considers the minimization of levelized cost of storage (LCOS) and power deviation to optimize the sizing and operation strategy of the hybrid energy storage system, and the optimization problem is solved by meta-heuristic algorithm and mixed-integer linear programming. The case studies show that: (1) the hybrid energy storage system is more reliable than single thermal energy storage and more cost-effective than single battery; (2) the multi-stage framework outperforms the commonly-used rule-based operation strategy; (3) demand response strategy can effectively reduce the investment cost of the proposed system.

Systematic decision-making framework for evaluation of process alternatives for sustainable ammonia (NH3) production

Ammonia (NH3) is the second highest produced chemical commodity worldwide, which commonly used in manufacturing of fertilisers, refrigerants, dyes and other chemicals. Haber Bosch process is the most established process to produce NH3 from hydrogen (H2) and nitrogen (N2). However, this process releases large amount of greenhouse gases (GHG) annually as this process consumes H2 which produces from steam methane reforming process that utilises methane (CH4) from natural gas. In addition, such process also consumes large quantity of energy to support the production of NH3. In order to enhance the sustainability of NH3 production, renewable energy (RE) such as solar can be used to replace the traditional energy system that consumes fossil fuels. Besides, production of H2 and N2 via water electrolysis and air separation technology which powered by RE can further enhance the sustainability of NH3 production. Such process is known as green NH3 production. One of the challenges of utilising RE is to have a stable supply of power. Therefore, concentrated solar power (CSP) is a good option to overcome this challenge, because it has capability of providing stable power supply. Based on literature review and market survey, a superstructure which consists of all possible and available technologies for production of green NH3 using CSP as an energy supply is presented. Next, the advantages and disadvantages of each alternative are evaluated and summarised in a comparison table. Ranking matrices are developed to evaluate and rank the alternatives quantitatively to determine the optimum pathway for green NH3 production. Based on the analysis, a conceptual integrated green NH3 production which involves a CSP tower plant with a two-tank molten salt thermal energy storage (TES) system is determined as the optimum pathway. Such process fulfils the electricity demand of a pressure swing adsorption (PSA) air separator, polymer electrolyte membrane (PEM) and NH3 synthesis plant. The results of this work are useful for feasibility studies on the commercialisation of green NH3 production.

The many-objective optimal design of renewable energy cogeneration system

To alleviate the issues of climate warming and fossil resources depletion, this paper proposes a wind-photovoltaic-thermal energy storage-electric heater cogeneration system, which adopts the structure of concentrated solar power plant but replaces the expensive collector field and tower with wind and photovoltaic farms and electric heater that converts the excess electricity as thermal energy source. The cogeneration system can effectively regulate the fluctuating wind and photovoltaic output to satisfy electricity load by electric heater based on resistive heating of molten salt, two-tank molten salt thermal energy storage and power block based on steam Rankine cycle, and supply heat load directly from the molten salt heat transfer fluid and heat exchanger. This paper considers minimizing levelized cost of energy, loss of power and heat supply probability, energy reduction rate and lifecycle equivalent CO2 emissions as optimized objectives, and investigates the many-objective (having four or more objectives) capacity optimization problem by Nondominated Sorting Genetic Algorithm-Ⅲ coupled with Principal Component Analysis and Technique for order preference by similarity to ideal solution. Moreover, residual analysis is applied to consider the uncertainty of wind power prediction. The detailed optimization process and performance comparison of many-objective algorithms, the all-year energy flow and seasonal output characteristics analysis of the optimal-compromise solution are presented. Finally, the proposed cogeneration system is compared to the power-only system with the same installed capacity and equivalent load demand, and the comparison results show that the proposed cogeneration system performs better in all evaluation metrics. Therefore, the proposed renewable energy cogeneration system is feasible and cost-effective for practical applications.

Compatibility of 3D-Printed Oxide Ceramics with Molten Chloride Salts for High-Temperature Thermal Energy Storage in Next-Generation CSP Plants

Oxide ceramics could be attractive high-temperature construction materials for critical structural parts in high-temperature molten salt thermal energy storage systems due to their excellent corrosion resistance and good mechanical properties. The 3D-printing technology allows the production of ceramic components with highly complex geometries, and therefore extends their applications. In this work, 3D-printed ZrO2 and Al2O3 ceramics were immersed in molten MgCl2/KCl/NaCl under argon or exposed in argon without molten chlorides at 700 °C for 600 h. Their material properties and microstructure were investigated through three-point-bend (3PB) testing and material analysis with SEM-EDX and XRD. The results show that the 3D-printed Al2O3 maintained its mechanical property after exposure in the strongly corrosive molten chloride salt. The 3D-printed ZrO2 had an enhanced 3PB strength after molten salt exposure, whereas no change was observed after exposure in argon at 700 °C. The material analysis shows that some of the ZrO2 on the sample surface changed its crystal structure and shape (T→M phase transformation) after molten salt exposure, which could be the reason for the enhanced 3PB strength. The thermodynamic calculation shows that the T→M transformation could be caused by the reaction of the Y2O3-stabilized ZrO2 with MgCl2 (mainly Y2O3 and ZrO2 with gaseous MgCl2). In conclusion, the 3D-printed ZrO2 and Al2O3 ceramics have excellent compatibility with corrosive molten chlorides at high temperatures and thus show a sound application potential as construction materials for molten chlorides.

Concentrated Solar Power Solar Tower with Oversized Solar Field and Molten Salt Thermal Energy Storage Working at an Annual Average Capacity Factor of 95% in NEOM City

Herein, a design for a concentrated solar power (CSP) plant solar tower (ST) with thermal energy storage (TES) by molten salt (MS) in NEOM city, a 100% renewable energy planned development, is presented. The novelty of the design is the oversized solar field, as well as the TES, to produce nearly constant power output every day of the year, with minimal reductions only in the winter months. A 95% annual average capacity factor is estimated to be delivered by this ST plant at a levelized cost of electricity (LCOE) of 7.84 c kWh−1. The CSP ST with 16 h of TES by MS is the best opportunity to deliver cost‐effective, fully dispatchable, reliable renewable energy, for both the economy and the environment. Other renewable energy options such as solar photovoltaic (PV) and wind may offer a lower LCOE even below 5 c kWh−1, but once battery storage is factored for dispatchability, the real cost increases by 14 c kWh−1. The proposed technology may deliver most of the electricity needed by NEOM city, with solar PV and wind plus batteries used for peak demand and to compensate for residual variability.

Thermodynamic performance comparison of various energy storage systems from source-to-electricity for renewable energy resources

This study discusses and thermodynamically analyzes several energy storage systems, namely; pumped-hydro, compressed air, hot water storage, molten salt thermal storage, hydrogen, ammonia, lithium-ion battery, Zn-air battery, redox flow battery, reversible fuel cells, supercapacitors, and superconducting magnetic storage through the first and second law of thermodynamics. By fixing an electrical output of 100 kW for all systems, the energy efficiencies obtained for the considered energy storage methods vary between 10.9% and 74.6% whereas, the exergy efficiencies range between 23.1% and 71.9%. The exergy destruction rates are also calculated for each system ranging from 1.640 kW to 356 kW. The highest destruction rate is obtained for the solar-driven molten salt thermal energy storage system since it includes thermal energy conversion via the heliostat field. Furthermore, the roundtrip efficiencies for the electrochemical and electromagnetic storage systems are compared with the analyzed systems, ranging from 58% to 94%. Renewable sources (solar, wind, ocean current, biomass, and geothermal) energy conversion efficiencies are also considered for the final round-trip performances. The molten salt and hot water systems are applicable to solar, geothermal, and biomass. The highest source-to-electricity efficiency is obtained for the super magnetic storage with 37.6% when using wind, ocean current, and biomass sources.

Comparative research of heat discharging characteristic of single tank molten salt thermal energy storage system

The single tank molten salt thermal energy storage (TES) system has been extensively studied due to its low cost and high efficiency performance. The binary nitrates (KNO3+Ca(NO3)2) is selected as heat storage medium in this study, which the melting point is 116.9 °C. This research aims to achieve stable and constant heat discharging performance of the single tank molten salt TES system. Three different inlet velocity conditions such as constant value, manual and automatic adjustment are comparatively studied. The results show that the heat discharging power drops with the heat discharging time increases under constant inlet velocity. The heat discharging time decreases with the increasing of inlet velocity while the heat discharging power increases with the increasing of the inlet velocity. The correlations between the inlet velocity and heat discharging time, the average temperature of molten salt in the single tank are proposed. The heat discharging power of manual and automatic adjustment of inlet velocity is in ±10% and ±3% fluctuation of the set value. The results could provide practical and effective guide to design the single tank molten salt TES system.

Design of a 100 MW Concentrated Solar Power Linear Fresnel plant with Molten Salt Thermal Energy Storage in Riyadh, Saudi Arabia

Our world has witnessed a rapid increase in power generation as a result of the growth of population and economy. Currently, people depend on conventional fuel energy as the main source of power generation; however, conventional fuel is well known for its limitation and impact on the environment. Thus, it was necessary to invest in an alternative source of energy such the solar power. Much research and development for solar power such as Concentrated solar power (CSP) have been implemented around the world, and it shows the capability to compete with conventional fuel technology. This paper aims to study the feasibility of constructing 100 MW CSP Linear Fresnel (LF) solar power in Riyadh, Saudi Arabia. In this study, the National Renewable Energy Laboratory (NREL) System Advisor Model (SAM) was used to design, simulate, and analyze the system. The system was designed based on CSP LF technology with molten salt thermal energy storage (TES), where TES supplies the power cycle with the required thermal energy after sunset. The result has revealed the system's capability to produce a good amount of solar power most of the year, reaching up to 38 GWh during summer. The LF system shows a good capacity factor (CF) exceeding 40%. The study shows that Saudi Arabia is a good place to install the CSP LF solar plant.

Novel design measures for optimizing the yearlong performance of a concentrating solar thermal power plant using thermal storage and a dry-cooled supercritical CO2 power block

Owing to water deficit and environmental concerns, the compatibility of dry cooling technology with supercritical CO2 (sCO2) power cycle in concentrated solar power (CSP) offers superior performance even at extreme climate temperatures. The CSP plant performance is expressively dominant by the erratic attributes of solar insolation and varying ambient temperature. In the present work, the dynamic attributes of the dry cooled sCO2 recompression cycle coupled with the central receiver is presented in terms of net power generation at different climate conditions. The supplementary bypass arrangement prior to the dry cooling tower ensures the system operating at the design point compressor inlet temperature in the occasion of low ambient temperatures. Solar tower plant with molten salt thermal energy storage is used to supply dispatchable electricity during nighttime. Based on the annual climate temperature profile, two sets of ambient air temperatures are selected for the cooling system design. This requires the rectification of two sets of design point main compressor inlet temperature/tower exit temperature at optimum turbine exhaust pressure in advance of the integration and design of the dry cooling tower. The key parameters of the solar system (cold tank temperature and molten salt split ratio) and power block (MCIT, pressure ratio, cycle mass, and bypass fraction) are optimized to maximize the power generation at any circumstances. The required height of the tower is 59 m and 67 m at two design points. The average net power using the minimum climate temperature is 23.71 MW and 24.09 MW respectively, whereas using the maximum climate temperature the values are 23.06 MW and 23.45 MW. The dynamic response from the system when the thermal energy storage operates during nighttime using additional bypass is demonstrated under the fluctuation of air temperature. The year-round plant performance as well as the dynamic response from the cooling tower of both cases are assessed with the historical air temperature data.

Modeling, transient simulations and parametric studies of parabolic trough collectors with thermal energy storage

For investigating the system response of parabolic trough collector heat generating system, a plant with parabolic trough collector field and two-tank molten salt thermal energy storage model with component-level control algorithm is developed for managing various working conditions. The model is transient inside the components and responds with hourly weather and demand data. The main purpose of this work is providing an alternative design methodology that focuses on the collector field, and storage size by investment, location, and load type.Using a simple economic model, the plant parameters are calculated, which contains only initial investment costs of the parabolic trough collector field and thermal energy storage costs. Depending on the economic model, various sizes of collector field and storage combinations are created at fixed initial investment costs in the mathematical model. A parametric study is performed by using the economic model simulating at several initial investment costs, two different locations in Turkey, and four different load profiles.As a result of the parametric study, maximum solar fraction cases are selected and the generalized trend is observed. The effect of thermal energy storage on the solar fraction is discussed and the change in thermal energy storage with optimum plant size is investigated. After the optimum investment, the linear increment trend of dispatchability is disappearing and increases asymptotically by increasing the plant and/or storage size. Later in this work, the significance of the load profile is emphasized, which should be one of the major design parameters for solar-powered energy systems.

An option for integration of Carnot Battery into a small Nuclear Power Plant

This article proposes a combination of nuclear power plant and grid-scale energy storage, classified as Carnot battery. The electric heater heats molten salts when excess electricity is available in the grid. The steam that is produced in a small modular nuclear reactor is heated with hot molten salts in the external super-heater. For continuous superheating to be ensured, the plant is equipped with molten salt thermal energy storage. The combined plant and reference NPP are modelled and simulated at steady-state conditions. Due to the higher turbine inlet temperature, the efficiency of the combined generation-storage nuclear plant is substantially improved. The proposed concept makes the co-location of NPP and Carnot Battery more attractive than the separate plants. The integrated thermal storage acts as secondary electricity storage. As such, it surpasses compressed air storage and is competitive with the pumped hydro storage, in the absence of their geographical and environmental constraints.