Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “levelized cost of heat”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Analysis of Carbon Capture Retrofits for Cement Plants

The objective of this study is to provide an estimate of the cost to capture CO 2 in retrofit applications at cement plants. The cement plant configurations considered in this study include natural gas and solid fuel (coal and coke) cases, and both wet- and dry kiln-fed plant designs, however the base cement plants in this study were not evaluated other than characterization of their kiln off-gas stream and high-level quantification of heat integration potential at the existing plant. In each case, the base cement plant produces 1.5 M tonnes per year of finished cement, assuming 91.4 percent clinker content. This analysis includes a 10 percent retrofit cost increase for process integration and low grade heat recovery, when compared to the analogous non-heat integration case. Heat integration is considered as a potential offset to capture system heating demands (i.e., as a percentage reduction). Recovery and reuse of excess heat from the base cement plant can provide economic benefits—primarily by reducing the need to purchase supplemental natural gas for CO 2 solvent regeneration—but any process improvement must be great enough to overcome the cost increases (i.e., capital and O&M) necessary to realize those benefits. With heat integration potential of 10 percent and 30 percent, that benefit wasn’t significant enough to offset the increase in capital and operating costs, and a cost of capture increase was observed based on the assumptions in this report. Benefits of heat integration potential may be realized when natural gas prices are higher, as demonstrated in the sensitivity to natural gas price where crossover points exist between heat integration cases and their respective non-heat integration cases. Four of the base cases were further evaluated to explore the cost implications of deeper levels of gas pre-treatment to remove oxides of nitrogen (NOx) and oxides of sulfur (SOx) from the kiln off-gas stream prior to CO 2 capture, purification, and compression. The results of these additional case analyses showed a 7.4–18.8 percent increase in cost of capture over the respective base case (i.e., analogous cases without SOx/NOx removal).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Making coal relevant for small scale applications: Modular gasification for syngas/engine CHP applications in challenging environments

Small-scale coal gasification technology, coupled to a reciprocating engine generator, has the potential for making coal a cost competitive resource for meeting the flexible energy needs and resiliency requirements of utilities across the United States. To maintain grid stability and reliability, electrical generation must be regulated to match the load at the proper voltage and frequency. With the expansion of intermittent sources into the grid, such as wind and solar, frequency and voltage regulation become increasingly important and challenging. This work presents the results of a Front End Engineering Design (FEED) effort to detail the engineering and preliminary economics of a small-scale, air blown, fixed-bed gasification process, operating at near-atmospheric pressure, with gas cleanup to provide syngas and pyrolysis liquid fuels for use in reciprocating engine generators for combined heat and power at the University of Alaska Fairbanks. A very detailed assessment of capital and operating costs allows the evaluation of a levelized cost of electricity of 208.06 $/MWh, which can be reduced through the selling of by-products (steam for heating purposes and pyrolysis liquids to be used for power generation in an existing diesel engine). Here, a combined sensitivity analysis, based on the Monte Carlo approach, has been carried out to evaluate the effects of the uncertainties (capital and operating costs and plant annual availability) on the LCOE.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2023

Techno-Economic Optimization of Advanced Energy Plants with Integrated Thermal, Mechanical, and Electro-Chemical Storage (Final Report)

The increasing use of renewable energy sources is leading to increased cycling of fossil-fueled power plants (FFPP) that are designed to operate at base-loaded conditions. Integrating energy storage facilities with the FFPPs can be helpful in reducing load-following operation of FFPPs. Decentralized deployment of energy storage facilities at the FFPP level has considerable advantages due to possibilities of smaller storage capacities, immediate benefits realized by the host power plant due to the increase in the efficiency, cleaner emission and higher plant life to name a few. Most importantly, deployment at the FFPP level can exploit the existing equipment items and facilities at the host power plant, thus reducing the CAPEX and reducing the storage capacity. However, realization of these benefits will critically depend on novel configuration/integration strategies with the least impact on the power plant operation and its configuration. Furthermore, dynamics of the entire integrated system including both the FFPP and the storage technologies must be taken into account to obtain the cost-optimal solution. With these motivations, the objective of this project was to complete a focused evaluation of decentralized deployments of energy storage facilities at the FFPP level. Promising thermal, chemical, mechanical, and electro-chemical storage technologies were evaluated with due consideration of their transient response to obtain various optimal system concepts that can minimize the levelized cost of storage. For thermal storage, cryogenic energy storage along with high temperature heat storage in molten salt as well as phase change material were evaluated. For mechanical storage, cryogenic air storage and pumped hydro storages were evaluated. For chemical storage, hydrogen storage was evaluated. For electrochemical storage, the team evaluated sodium sulfur, vanadium redox flow battery as well as Li-ion batteries. Integration of these storage technologies with the natural gas combined cycle (NGCC) and supercritical pulverized coal (SCPC) plants was considered. Six technologies, namely molten salt, cryogenics, compressed air, pumped hydro, H2 storage and Li-ion battery storage, were downselected based on their levelized cost of storage. It was observed that the ranking of the optimal storage technology can differ based on the host power plant technology even when same demand/supply/price profile for electricity are considered. It was also observed that as the variability in power demand varies, the ranking of the optimal storage technologies vary. However, for the same demand and LMP profile, top six optimal storage technologies for NGCC vs SCPC plants did not differ much even though LCOS for the same technology and optimal size of a given storage technology did differ. Detailed techno-economic assessment of these six technologies was undertaken.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2021

On-Sun Testing of a High-Temperature Solar Receiver's Flux Distribution

Concentrated solar power (CSP) is a promising technology in transitioning to renewable energy because of its abundance in nature and thermal energy storage (TES) capability. Among the four types of available CSP technology, including parabolic trough, linear Fresnel, power tower, and parabolic dishes, a power tower using a central receiver has more potential to generate high-temperature heat in a scale supporting power cycles efficiency and achieve low levelized cost of energy (LCOE). Other than the conventional type of receiver design, the high-absorptive receiver concept developed and presented in this paper is novel in its design approach. The novel receiver design originated from National Renewable Energy Laboratory (NREL) consists of an array of solar flux absorb tubes. The solar absorb tubes require uniform flux distribution and in-depth flux penetration through the three different reflective sections of tubes in a hexagonal shape. To evaluate this unique receiver design and thermal performance, the flux distribution, flux uniformity, and intensity were numerically simulated using ansys fluent and SolTrace modeling program. On-sun testing has been done at NREL high flux solar testing facility, based on the computational analysis.

clean energy↗
DOE OSTI2024

Electromagnetic Energy-Assisted Thermal Conversion of Fossil-Based Hydrocarbons to Low-Cost Hydrogen

The goal of this project was to develop and optimize catalysts for methane decomposition, particularly focusing on regeneration via an electromagnetic energy-assisted mechanism, to produce hydrogen more cost-effectively compared to electrolysis routes. To achieve this goal, the project pursued several key objectives. The project began with the preparation and testing of various catalysts. A nickel-silica based catalyst was identified as the most promising material for the pyrolysis of methane into carbon and hydrogen. Kinetic parameters for methane decomposition were determined, aiding in computational modeling efforts. Structured catalysts were investigated, highlighting the need for frequent cleaning or regeneration to maintain performance, with methane conversion rates exceeding 70% in tube furnace tests. Computational fluid dynamics modeling was employed to optimize reactor designs and electrode angles, leading the project team to propose a multi-compartment thermal conversion system for larger setups. This modeling work was important in understanding reaction characteristics, carbon deposition rates, and temperature profiles under various conditions. A bench-scale reactor system was assembled to evaluate catalyst regeneration using electromagnetic energy-assisted mechanisms. Experiments demonstrated the potential for carbon removal, though further optimization is needed. The carbon produced from the methane conversion process was evaluated for potential use in lithium-ion battery electrodes. The carbon exhibited properties similar to commercially available high-purity multi-walled carbon nanotubes and nanofibers, with a carbon content greater than 95%. Coin cell batteries assembled with this carbon showed that lower replacement levels (10% to 33%) outperformed the control group, improving specific capacity density and stability. However, higher replacement levels (100%) demonstrated poorer performance, suggesting that excessive carbon substitution negatively impacts battery performance. These findings indicate the potential marketability of the produced carbon as a component in lithium-ion batteries, though further testing is necessary to confirm long-term advantages and disadvantages associated with the use of the carbon product. These results however justified further technoeconomic assessments to determine if the process can provide low-cost hydrogen. The economic feasibility and technical performance of methane decomposition for hydrogen production were assessed, focusing on three plant configurations: 100E (electrically heated), 100C (combustion heated using produced hydrogen), and PE-Hybrid (a combination of pyrolysis (indicating decomposition) and electrolysis). The Levelized Cost of Hydrogen (LCOH) for the pyrolysis configurations was found to be approximately 25% lower than that of electrolysis. The 100E configuration had the lowest LCOH at $\$$3.12/kg. Including carbon product sales significantly improved the economics, with the 100C configuration achieving a negative LCOH of -$\$$0.35/kg. The PE-Hybrid configuration was not economically advantageous compared to pure pyrolysis plants due to its complexity and additional equipment requirements. Ultimately, methane pyrolysis presents a viable method for near carbon dioxide-free hydrogen production, with significant economic advantages over electrolysis, especially when considering the sale of carbon byproducts. The 100E and 100C configurations showed the most promise, with the choice between them ultimately depending on the prices of power and natural gas. In conclusion, this technology has the potential to lower hydrogen production costs by leveraging the methane decomposition process with the sale of valuable carbon byproducts. By optimizing catalyst performance and integrating electromagnetic energy-assisted regeneration, the process can achieve higher efficiency and economic viability, making it a competitive alternative to traditional hydrogen production methods.

08 HYDROGEN↗
DOE OSTI2025

Optimizing district energy systems under uncertainty: Insights from a case study from Washington D.C., USA

This study investigates solutions for delivering affordable heating and cooling to a brownfield site, focusing on a case study in Washington, DC. Moving towards more diverse and resilient energy systems, we identify the optimal portfolio for a district energy system with diverse energy sources to meet the area’s energy demands. Our methodological approach integrates two detailed models: one calculating building-level energy demand and the other optimizing district energy technology choices based on their demand profiles, accounting for uncertainties in energy prices, policies, and other parameters. The results provide an economic comparison of district and individual supply options at the building level, emphasizing the flexibility district systems can offer to the electricity sector. District energy systems demonstrate cost-stabilization benefits amidst volatile energy prices and external uncertainties. For heating, district systems yield significant cost savings compared to individual solutions, driven by fuel flexibility and the use of local renewable energy sources. For cooling, district systems also show advantages, though individual systems may remain more cost-effective for smaller buildings. Additionally, district systems exhibit considerable flexibility on the heating side, as evidenced by variations in electricity consumption. We recommend future research to explore the relationship between the economics of district energy systems, particularly at the building level, and their flexibility potential for the electricity sector across diverse geographic contexts to reduce overall grid costs and promote grid reliability. This includes areas with distinct zoning laws, municipal priorities, utility structures, and funding mechanisms, such as the United States, and regions like Europe with pronounced electricity price volatility.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2025

Renewable Energy Potential Model: Hawaii Geothermal Supply Curves

This dataset extends the development of the Renewable Energy Potential (reV) model to include geothermal energy, with a specific focus on Hawaii. Provided here are the results of two scenarios that were modeled for geothermal energy in Hawaii: binary enhanced geothermal systems (EGS) at a depth of 2.5 km and hydrothermal binary systems at a depth of 1.5 km. The resource data for both scenarios were derived from Lautze and Haskins (2024) using an exponential method. The PFA probability of heat map was used as a look up table for which temperature gradient to use (Lautze and Haskins, 2024). The dataset provides geospatial and techno-economic details for evaluating geothermal energy potential. It includes spatial coordinates, estimated capacity factors, developable area, resource potential, and annual energy production metrics. Economic details such as levelized cost of electricity (LCOE), site development costs, transmission costs, and fixed-charge rates are also included. The reV model, originally developed for wind and solar energy, incorporates these variables to evaluate deployment constraints related to land use, environmental and cultural factors, and grid integration.

15 GEOTHERMAL ENERGY↗
NASA NTRS1975

Shuttle launched flight tests - Supporting technology for planetary entry missions

The feasibility of conducting Space Shuttle-launched earth entry flight tests to enhance the technology base for second generation planetary entry missions is examined. Outer planet entry environments are reviewed, translated into earth entry requirements and used to establish entry test system design and cost characteristics. Entry speeds up to those needed to simulate radiative heating levels of more than 30 kW/sq cm are shown to be possible. A standardized recoverable test bed concept is described that is capable of accommodating a wide range of entry technology experiments. The economic advantage of shared Shuttle launches are shown to be achievable through a test system configured to the volume constraints of a single Spacelab pallet using existing propulsion components.

Vetter, H. C.↗
NASA NTRS2016

Heat Exchanger Performance Impacts on Optimum Cost Conditions in Thermoelectric Energy Recovery Designs

Cost is just as important as power density or efficiency for the adoption of waste heat recovery thermoelectric generators (TEG). Prior work [1] has shown that the system design that minimizes cost (e.g., the $/W value) can be close to the designs that maximize the system’s efficiency or power density, however, it is important to understand the relationship between those designs to optimize TEG performance-cost compromises. Expanding on recent work [1, 2, 3] the impact of heat exchanger conditions on the optimum TEG fill factors and cost scaling of a waste heat recovery thermoelectric generator with a detailed treatment of the hot side exhaust heat exchanger has been investigated further. The effect of the heat lost to the environment and updated relationships between the hot-side and cold-side conductances [4] that maximize power output are considered. The optimum fill factor to minimize TEG energy recovery system costs is strongly dependent on the heat leakage fraction, σ, the mass flow rate of the exhaust, the hot-side heat exchanger effectiveness, heat exchanger UAh, and heat flux. These relationships are explored and characterized for typical exhaust gas-flow conditions to show the inherent design complexities. The heat exchanger costs often dominate the TEG cost equation and it is critical to fully understand the tradeoff between heat exchanger performance, optimum TEG fill factors, and cost to establish potentially optimum design points within the cost-performance design space. This work will explore the design tradeoffs and relationships within the cost-efficiency-power density design space for a typical thermoelectric energy recovery system application. The interplay between optimum TEG fill factors and heat exchanger design can impact system footprint, volume, and mass in weight-sensitive applications. Less-effective, low-cost heat exchangers may outperform higher cost alternatives from a market adoption perspective. This shift of emphasis acknowledging the interdependence of optimum TEG fill factors and heat exchanger performance has significant implications on thermoelectric waste heat recovery systems designs and their operation. In addition, preferred TEG design regimes exist that accommodate reasonable compromises in TE performance and cost. This effort highlights how the optimum fill factor–heat exchanger performance relations couple to these optimum TEG performance-cost domains based on TEG-system-level analyses and provides a focus for future system research and development efforts.

Energy recovery↗
DOE OSTI2021

Potential Early Markets for Fusion Energy

We examine potential early markets for fusion energy and their projected cost targets, based on analysis and synthesis of many relevant, recent studies and reports. Seeking to provide guidance to ambitious fusion developers aspiring to enable commercial deployment before 2040, we examine cost requirements for fusion-generated electricity, process heat, and hydrogen production based on today’s market prices but with various adjustments relating to possible scenarios in 2035, such as ‘‘business-as-usual,’’ high renewables penetration, and carbon pricing up to 100 $/tCO 2 . Key findings are that fusion developers should consider focusing initially on high-priced global electricity markets and consider including integrated thermal storage, depending on techno-economic factors, in order to maximize revenue and compete in markets with high renewables penetration. Process heat and hydrogen production will be tough early markets for fusion, but may open up to fusion as markets evolve and if fusion’s levelized cost of electricity falls below 50 $/MWh e . Finally, we discuss potential ways for a fusion plant to increase revenue via cogeneration (e.g., desalination, direct air capture, or district heating) and to lower capital costs (e.g., by minimizing construction times and interest or by retrofitting coal plants).

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2024

Utilizing waste heat in wastewater treatment plants for water desalination: Modeling and Multi-Objective optimization of a Multi-Effect desalination system using Decision Tree Regression and Pelican optimization algorithm

This paper examines the feasibility of using waste heat from wastewater treatment plants (WWTPs) for water desalination. A model was developed to utilize waste heat from the gensets at As Samra WWTP in Jordan, using real data and TRNSYS® software to calculate available waste heat. The desalination process was then modeled with ASPEN PLUS® software, focusing on multi-effect desalination (MED). Both series and parallel configurations for the MED system were compared. The study investigated the effects of system feeding flow rate, feeding pressure, and heat input on productivity, performance ratio, and recovery ratio. The study also introduces a novel optimization technique combining machine learning and modern optimization algorithms to maximize system productivity and performance. Initially, a decision tree regression (DTR) model is developed to establish relationships between key independent variables (flow rate, feed pressure, and heat input) and dependent variables (productivity, performance ratio, and recovery ratio). The Pelican Optimization Algorithm (POA) is then used to identify the optimal values of the independent variables for maximum productivity and performance. The results show that using a series configuration yields a system productivity of 3984.2 kg/hr, a performance ratio of 3.78, and a recovery ratio of 0.991 at a feed flow rate of 4000 kg/hr, feed pressure of 3 bars, and heat input of 719 kW. Optimal productivity (4421 kg/hr), performance ratio (3.81), and recovery ratio (0.851) are achieved at a feed flow rate of 5166 kg/hr, feed pressure of 3.2 bars, and heat input of 794 kW. In conclusion, the techno-economic assessment indicates a levelized cost of water of 1.63 USD/m 3 for parallel configurations and 1.65 USD/m 3 for series configurations, with a payback period of less than two years.

42 ENGINEERING↗
DOE OSTI2021

Design of a 2 MW ZrC/W-based molten-salt-to-sCO 2 PCHE for concentrated solar power

To increase the power cycle efficiency and lower the levelized cost of electricity (LCOE) of concentrated solar power (CSP) plants, printed circuit heat exchangers (PCHEs) capable of operating above 700 °C with molten chloride salt and a sCO 2 -based fluid are needed. In this paper, the design of a high-pressure, high-temperature, 2 MW PCHE comprised of a thermomechanically-robust, zirconium carbide/tungsten (ZrC/W) composite is conducted for CSP plants. The ZrC/W composite is a material with high thermal conductivity, high stiffness, and high failure strength at high temperatures, along with excellent resistance to thermal cycling and thermal shock. In this work, a thermomechanical design analysis was conducted to select appropriate material thicknesses of the ZrC/W plates, and to determine the geometrical dimensions and the thermal performance of the PCHE. The influences of the plate number and heat exchanger length on power density and pressure drop have also been systematically investigated. Economic analyses were conducted to compare the cost of ZrC/W-based PCHEs to those comprised of IN740H (a state-of-the-art, nickel-based superalloy) and 316 stainless steel (316SS). Finally, at a sufficiently high plate production rate, the manufacturing cost of ZrC/W-based PCHEs can be significantly lower, while achieving a much higher power density, compared with state-of-the-art, nickel alloy-based and stainless steel-based PCHEs.

14 SOLAR ENERGY↗
DOE OSTI2025

Advancing Pumped Thermal Energy Storage Performance and Cost Using Silica Storage Media

Pumped Thermal Energy Storage (PTES) is an electricity storage system that is suitable for long-duration energy storage (10-1000 h) due to its low marginal cost of energy capacity. We present a techno-economic model of a PTES system that uses particle thermal energy storage. Particles have low costs and can be operated over a wide temperature range leading to increased efficiency and reduced costs compared to other PTES designs. We show how the round-trip efficiency, specific power output, capital cost, and levelized cost of storage (LCOS) depend on parameters such as the pressure ratio, heat exchanger approach temperature and pressure loss, and maximum temperature. We compare particle-PTES (P-PTES) performance to PTES which uses liquid thermal energy storage - i.e. molten salt hot storage and methanol cold storage (MS-PTES). We find that using silica particles for storage advances PTES technology: P-PTES can be operated at higher maximum temperatures than MS-PTES. Furthermore, P-PTES can achieve lower approach temperatures in the heat exchangers than MS-PTES without increasing capital costs, because P-PTES uses direct-contact heat transfer in fluidized bed heat exchangers. As a result, we find that P-PTES systems achieve higher round-trip efficiency than MS-PTES (66 % versus 57 %) and lower LCOS (e.g. 0.115 +- 0.03 $/kWhe versus 0.171 +- 0.04 $/kWhe for 10 h discharge). The low cost of particles and containment means that P-PTES can provide long-duration energy storage at low capital cost per unit energy capacity. For example, the total capital cost per unit energy reduces from 245 $/kWhe at 10 h to 38 $/kWhe at 100 h. These costs are considerably lower than MS-PTES (72 $/kWhe at 100 h) and also outcompete current and future Li-ion battery system projections (100-265 $/kWhe).

25 ENERGY STORAGE↗
DOE OSTI2022

Mechanically-, Thermally, and Chemically-Robust High-Temperature Ceramic Composites

In an effort to lower the levelized cost of electricity generated by Concentrated Solar Power (CSP) plants, the heat-to-electricity conversion efficiency may be increased by operating such plants with higher turbine inlet temperatures using closed Brayton cycles with high-pressure, supercritical carbon dioxide (sCO 2 ) as the working fluid. For example, if the turbine inlet temperature is raised to ≥750°C, in combination with sCO2 closed Brayton cycles, the relative heat-to-electricity efficiency may be raised by more than 20% (compared to subcritical steam Rankine cycles operating with turbine inlet temperatures ≤550°C). The associated reduction in the cost of dispatchable electricity from such CSP plants (utilizing high-temperature thermal energy storage) would be an important breakthrough on the path towards direct competition with fossil-fuel-based plants. A key barrier to achieve such high-temperature efficient operation has been the limited thermomechanical performance of metal alloys used in compact, primary printed circuit- type heat exchangers (PCHEXs) for heat transfer to high-pressure sCO 2 . The maximum allowed stresses for the use of conventional stainless steels and nickel-based superalloys at high sCO 2 pressures (≥20 MPa) decline rapidly at temperatures ≥550°C. This project has been focused on demonstrating the desired high-temperature properties and attractive manufacturing characteristics of mechanically-, thermally-, and chemically-robust ceramic/metal composites (cermets), in order to allow for the use of such composites in primary PCHEXs for heat transfer to sCO 2 at ≥750°C and ≥20 MPa in CSP plants. Prior work with high-temperature, co-continuous carbide/refractory metal cermets, such as ZrC/W composites, has already demonstrated: i) the attractive combination of high-temperature properties exhibited by such materials (e.g., high values of stiffness, failure strength, and thermal conductivity at 800°C), and ii) cost-effective processes for manufacturing PCHEX plates comprised of such cermets with tailorable channel patterns. However, ZrC/W cermets were not found to be inherently corrosion resistant in sCO 2 at 750°C and 20 MPa. While the application of a Cu coating to ZrC/W surfaces, along with a modest addition (50 ppm) of CO to CO 2 , rendered such composites resistant to corrosion for 1000 h in such sCO 2 -based fluids at 750°C, such additional steps would increase the design complexity of such cermet-based components. An alternative approach (the focus of this project) is to develop mechanically-robust, cost- effective cermets that are inherently resistant to high-temperature oxidation in air and CO 2 . The overall goals of this project have been to demonstrate: i) the oxidation resistance of at least one cermet at 750°C in air and in CO 2 (i.e., with a projected annual corrosion ≤30 μm), ii) the mechanically robust nature of at least one cermet at 750°C (i.e., with an average failure strength ≥200 MPa), and iii) that the selected cermet can be manufactured via low-cost forming techniques.

14 SOLAR ENERGY↗
NASA NTRS2010

NASA Puffin Electric Tailsitter VTOL Concept

Electric propulsion offers dramatic new vehicle mission capabilities, not possible with turbine or reciprocating engines; including high reliability and efficiency, low engine weight and maintenance, low cooling drag and volume required, very low noise and vibration, and zero emissions. The only penalizing characteristic of electric propulsion is the current energy storage technology level, which is set to triple over the next 5-10 years through huge new investments in this field. Most importantly, electric propulsion offers incredible new degrees of freedom in aircraft system integration to achieve unprecedented levels of aerodynamic, propulsive, control, and structural synergistic coupling. A unique characteristic of electric propulsion is that the technology is nearly scale-free, permitting small motors to be parallelized for fail-safe redundancy, or distributed across the airframe for tightly coupled interdisciplinary functionality without significant impacts in motor-controller efficiency or specific weight. Maximizing the potential benefit of electric propulsion is dependent on applying this technology to synergistic mission concepts. The vehicle missions with the most benefit include those which constrain environmental impact (or limit noise, exhaust, or emission signatures) are short range, or where large differences exist in the propulsion system sizing between takeoff and cruise conditions. Electric propulsion offers the following unique capabilities that other propulsion systems can t provide for short range Vertical Takeoff and Landing (VTOL) aircraft; elimination of engine noise and emissions, drastic reduction in engine cooling and radiated heat, drastic reduction in vehicle vibration levels, drastic improvement in reliability and operating costs, variable speed output at full power, for improved cruise efficiency at low tip-speed, elimination of high/hot sizing penalty, and reduction of engine-out penalties.

Moore, Mark D.↗
DOE OSTI2020

Analysis of the Impurity MgOHCl in Molten Chloride Salts Toward its Electrochemical Removal from CSP Plants During Operation

The work presented here is a study of the impurity MgOHCl in molten chloride salts, toward the eventual goal of electrochemically removing it from operational molten-chloride-based concentrating solar power (CSP) plants.1,2 Implementation of molten chloride salts as a heat transfer fluid is among the most promising pathways for decreasing the levelized cost of energy (LCOE) of CSP systems because its high thermal stability allows higher operating temperatures, and thus, greater efficiency. However, this impurity - formed when MgCl2 salts are exposed to air and moisture - cause significant corrosion of containment alloys.1 Therefore, we have developed and validated in a laboratory setting: 1) a method for the formation of MgOHCl for controlled impurity spike in molten salt for its further sensing, evaluation, and reduction; 2) evaluated its diffusion in the molten salt, and 3) began assessing its electrochemical properties. Our findings allow us to propose solutions for efficiently and instantly removing MgOHCl from an operational CSP plant.

concentrated solar power↗
DOE OSTI2026

A comparative assessment of the economic viability of nuclear-integrated direct air capture systems

Direct air capture (DAC) systems require heat and electricity to operate, which can be supplied by nuclear power plants (NPPs). In this study, the performance and cost of various conceptual nuclear-DAC systems are assessed, and their performance is compared with several non-nuclear options. Three nuclear-DAC systems are considered: (1) a liquid solvent direct air capture (L-DAC) system with heat supplied from natural gas (NG) and electricity supplied by an NPP, (2) an electrified L-DAC system, fully powered by electricity from an NPP, and (3) a solid sorbent direct air capture (S-DAC) system utilizing both heat and electricity generated by an NPP. Two nuclear technologies are considered: a pressurized water reactor and a high-temperature gas-cooled reactor. Under the medium conservatism scenario, the levelized cost of direct air capture (LCOD) for these systems range from $\$$310/tCO 2 to $\$$525/tCO 2 with the L-DAC system having an NG heat supply at the lower end of the range, and the electrified L-DAC system and the S-DAC system at the higher end of the range. Coupling with nuclear energy led to a 21 % reduction in LCOD for the L-DAC system with NG heat supply and a 29 % reduction for the S-DAC system when compared to fully NG-powered options. When powering the DAC system with grid electricity, the LCOD is highly dependent on the assumed electricity price and carbon intensity. The nuclear option is the cheaper choice when the price of low-carbon grid electricity exceeds $\$$95/MWh and $\$$45/MWh for the L-DAC and S-DAC systems, respectively.

22 - GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2022

Preliminary Pilot-scale Study and Techno-economic Analysis of Chemical Heat Pump with Conventional Nuclear Reactors

The energy economy is continually evolving, particularly in terms of primary energy sources, their conversions to useful forms such as electricity and heat, and their utilization in different sectors, in response to socio-political factors. Because nuclear source is clean and non-carbon-emitting energy source, it is crucial to consider its role in the evolution of the energy economy. A pilot-scale study was conducted for Chemical Heat Pump (ChHP) system at three different scales (25-, 100-, and 1000-kW thermal outputs) using steady state thermal model. To establish the viability of selling heat rather than electricity alone, techno-economic analysis was undertaken for advanced Small Modular Reactor (SMR), and SMR paired with varied thermal output ChHP systems was referred to as the nuclear hybrid energy system (NHES) in this study. Using the U.S. Energy Information Administration statistics, pricing for electricity and natural gas were anticipated for U.S. regions (California, Northwest, Midwest, Southwest, New England, and PJM). Based on thermal output from ChHP, advanced SMR with 100 MWth and four alternative NHES scenarios were explored, namely 50-, 10-, 5-, and 1-MWth. Net present value, payback period, discounted cash flow return, and levelized cost of energy were evaluated for all scenarios. Based on the economic analysis, selling heat to high-temperature industrial processes is more profitable compared to selling electricity only. Higher carbon taxes showed significant improvement in economic parameters for NHESs. Providing heat to high-temperature industries could be beneficial, helping to reduce the greenhouse gas emissions by slashing the fossil fuel consumption.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗