Integrated Energy Systems
Publications
Modeling Microreactor Requirements for High-Performance Computing
The potential deployment of microreactors as a zero-emission source for critical applications within integrated energy systems such as microgrids has been gaining interest in recent years owing to the microreactors’ dispatchable nature, modular design, small site footprint, and carbon-free generation. A particularly high-value but challenging application with rapidly growing demand is in the deployment of high-performance computing (HPC) clusters within microgrids. In this work, a model of a HPC cluster in an energy-diverse microgrid is developed to determine the requirements of a technology-agnostic microreactor deployed for such a challenging application. The minute-resolution simulations revealed that the cluster’s electrical load fluctuation of up to 4.1 MW/min required a fast and responsive load-following capability. When the load-following capability of the microreactor was perturbed, the required microgrid storage capacity associated with having a 0.1 MW/min dispatchable microreactor decreased by two orders of magnitude as compared with load-following solely by energy storage devices, indicating that load-following capability in microreactors is of great value in such applications. The analysis methods described in this work can be extended to other microgrids, other HPC clusters, or other types of challenging applications, and can help microgrid planners in determining the storage size, output capacity, and ramping capabilities of the storage devices required for a given microgrid configuration.
Nuclear waste heat use in agriculture: History and opportunities in the United States
Nuclear power plants (NPPs) produce a large amount of waste heat (WH) that has generally been perceived and regulated as an environmental liability. Given the abundance of WH from NPPs and the ubiquity of generally low-grade heat requirements of agricultural operations, from production to post-harvest, there is remarkable potential to harness NPP WH for agricultural uses with mutual economic advantages to NPPs and agricultural sectors. Taking advantage of this WH resource may improve the financial outlook of both the partnered power plants and agricultural businesses by providing an additional revenue stream, decreased heating costs, and a reduced carbon footprint. This review summarizes and interprets the historical discourse and research on agricultural applications of NPP WH in the U.S., and synthesizes technical constraints, unknowns, and opportunities for realizing the benefits of WH derived from the nuclear energy sector for agricultural value chains. Previous applications of WH in the agricultural industry demonstrate that this is a viable option to the benefit of the parties involved under the right conditions, but relatively little has been done to further this technology in the U.S. in recent years or explore novel applications. A revival of interest in this technology may be warranted given the current outlook for NPPs in the U.S. and a general interest in reducing the environmental impact of agriculture.
Modeling of an Energy-Diverse Embedded Grid for Microreactor Integration
Microreactors present an opportunity to revolutionize the role of nuclear energy via the development of these technologies in a diverse and distributed energy network for a clean energy future. Because of the limited output of these novel systems, the deployment of microreactors should be focused on high-value applications in order to realize their full potential. This involves understanding the microreactor performance and how it interacts with the preexisting infrastructure. In this work, an energy-diverse embedded grid is modeled using OpenModelica in order to study the impact of microreactor integration under several distinct deployment approaches. The University of Illinois at Urbana-Champaign (UIUC) is used as a prototypic market due to its well-characterized energy ecosystem with available extensive real-time and historical data. The UIUC model recreates the existing chilled-water, steam, and electricity infrastructure, including wind, solar, and cogeneration sources. The infrastructure model simulates the interplay between the three utilities and how different microreactor integration approaches would impact UIUC’s embedded grid. From this study, the deployment of a single microreactor under electric load-conditioning, steam production retrofit, or a hybrid of both is found to be the most appropriate in consideration of their unique advantages toward cost savings and grid resilience. Meanwhile, if grid resiliency is not a main objective, the greatest emissions reduction and cost-savings benefits can be obtained by operating the reactor in a base-loading configuration. This study employed historically low coal and gas prices and provided a conservatively low estimate for the benefits from a microreactor. Given the price volatility of fossil fuels, the benefits of the microreactor are expected to be greater than this estimate. Finally, the modular nature of the modeling framework allows for an extension of the analysis to other similar embedded grids.
Analysis of Microreactor Efficacy with Hydrogen Production Methods
A major issue with the economic validity of nuclear power technologies is their rate of return on investment. Since these systems have high expected initial capital costs, it is difficult to instill investment confidence against the backdrop of untested construction and operation. Nonetheless, emerging nuclear technologies such as microreactors remain promising as their output is carbon-free and the high outlet temperature associated with many microreactor concepts enables them to generate process heat that can power industrial processes, thereby widening their versatility beyond electricity generation. The pairing of these systems with higher value commodities, such as hydrogen, could potentially improve the economic viability of microreactors. Hydrogen production has become a subject of great interest in recent years for numerous applications such as for transportation, metal refining, and fertilizers. With a profitable microreactor-powered hydrogen production system, the price dependency of these applications and downstream commodities on the volatile natural gas prices can be reduced. In this work, the pairing of a microreactor with natural gas reforming (NGR) and high-temperature electrolysis (HTE) was modeled and it was found that a 10 MWth to 20 MWth microreactor could become economically viable through revenue from hydrogen production. The technology-agnostic microreactor energy source paired with the NGR and HTE plants was able to generate achievable principal loan values that were above $4.5 M/MWth for a 15 MWth reactor over a 20-year period. The cost of a first-of-a-kind microreactor according to available estimates exceeded the average achievable loan values for the HTE system while the NGR system was able to achieve these estimates within 21 years. The pairing of HTE with autothermal reforming was also investigated and it was found to be uncompetitive as compared with NGR and HTE.
Coupling and Economic Analysis of Nuclear Microreactor Enabled Ammonia Production
Nuclear microreactors present a promising opportunity for the deployment of nuclear power technologies due to their anticipated lower initial capital costs. Even so, the rate at which investment costs are recovered remains a concern with the technology and acts as a barrier to its deployment. The economics of many microreactor concepts may be improved by leveraging the high-temperature heat that they generate for powering chemical processes with high value products such as ammonia. Ammonia is of particular interest due to an existing mature market in fertilizer applications and is currently experiencing a rise in market price. Pairing ammonia production with microreactors could increase their economic competitiveness while still providing a stable demand that enables efficient baseload operation. In this work, microreactor driven ammonia production was modeled for systems based on natural gas reforming (NGR) and high-temperature electrolysis (HTE) for steady-state operation and economic viability was demonstrated for 10 MWth to 20 MWth microreactors. The NGR based system demonstrated a netback against estimated costs for a between first-of-a-kind and nth-of-a-kind (BOAK) reactor in 8 years but required a carbon tax exceeding $75.6/tonneCO2 to be competitive with existing ammonia production plants. The HTE based system meanwhile achieved a netback in 18 years and its competitiveness with renewable electricity-based ammonia production depended on the assumptions around electricity costs. When more moderate ammonia market prices were considered, the NGR based system required 17 years to achieve a netback while the HTE system was unable to do so in the studied pay off period of 25 years.
Nuclear Microreactors and Thermal Integration with Hydrogen Generation Processes
Nuclear microreactors offer reliable, low-carbon dispatchable power and heat for various end use applications. Although the direct electricity end uses are straightforward, the feasibility of microreactors’ integration for thermal end use has not been analyzed in literature in sufficient detail. Delivering process heat generated by nuclear microreactors to supply the high temperatures essential for hydrogen production has been proposed as one cogeneration option that can further aid in the alleviation of climate change, since hydrogen can replace carbon-emitting fuels such as gasoline, diesel or natural gas. This review provides a novel perspective on the intersection of microreactors and process heat use by investigating hydrogen production technologies, microreactor designs and process heat integration options. A comprehensive overview of hydrogen production methods including electrolysis and thermochemical conversions of hydrocarbons and water is presented by classifying the methods based on process temperatures and maturity. Additionally, an in-depth summary detailing the reactor type, power output, and maximum operating temperature of many prospective microreactor designs has been created. Finally, heat transfer options for integrating microreactors to hydrogen production systems were evaluated. The intermediate heat exchanger (IHX) assessment considers IHX material, IHX type, and heat transfer media utilized within the apparatus.
Modeling Microreactor Requirements for High-Performance Computing
The potential deployment of microreactors as a zero-emission source for critical applications within integrated energy systems such as microgrids has been gaining interest in recent years owing to the microreactors’ dispatchable nature, modular design, small site footprint, and carbon-free generation. A particularly high-value but challenging application with rapidly growing demand is in the deployment of high-performance computing (HPC) clusters within microgrids. In this work, a model of a HPC cluster in an energy-diverse microgrid is developed to determine the requirements of a technology-agnostic microreactor deployed for such a challenging application. The minute-resolution simulations revealed that the cluster’s electrical load fluctuation of up to 4.1 MW/min required a fast and responsive load-following capability. When the load-following capability of the microreactor was perturbed, the required microgrid storage capacity associated with having a 0.1 MW/min dispatchable microreactor decreased by two orders of magnitude as compared with load-following solely by energy storage devices, indicating that load-following capability in microreactors is of great value in such applications. The analysis methods described in this work can be extended to other microgrids, other HPC clusters, or other types of challenging applications, and can help microgrid planners in determining the storage size, output capacity, and ramping capabilities of the storage devices required for a given microgrid configuration.
Detailed reviews of a past advanced nuclear reactor–based integrated energy system, as well as other nuclear reactor and fossil fuel–based integrated energy systems, have been performed for this work. A review of the utilization of heat from nuclear reactors for various applications and cogeneration has been done. The heat can be utilized by extracting the steam from the turbine while the steam is still at a desired temperature. While the use of nuclear process heat for district heating in countries like Finland, France, China, Poland, and elsewhere is discussed, more focus of the review has been given to nuclear desalination processes.
Integrated energy systems (IESs), where distinct types of reactors like pressurized water reactors, boiling water reactors, sodium-cooled fast reactors, heavy water reactors, and other advanced reactors are coupled with various nuclear desalination processes, like multi-effect distillation (MED), multistage flashing, and reverse osmosis methods, are discussed. The nuclear desalination plant at Aktau is discussed in more detail due to its decades of successful operation. The IES of the Aktau plant coupled with a five-effect MED desalination plant was taken as a reference for modeling the Open Modelica (OM)–based IES in this work. The OM IES model shows good agreement with the MED plant output of Aktau and can be extended for future applications of IESs.
Coupling and Economic Analysis of Nuclear Microreactor Enabled Ammonia Production
Nuclear microreactors present a promising opportunity for the deployment of nuclear power technologies due to their anticipated lower initial capital costs. Even so, the rate at which investment costs are recovered remains a concern with the technology and acts as a barrier to its deployment. The economics of many microreactor concepts may be improved by leveraging the high-temperature heat that they generate for powering chemical processes with high value products such as ammonia. Ammonia is of particular interest due to an existing mature market in fertilizer applications and is currently experiencing a rise in market price. Pairing ammonia production with microreactors could increase their economic competitiveness while still providing a stable demand that enables efficient baseload operation. In this work, microreactor driven ammonia production was modeled for systems based on natural gas reforming (NGR) and high-temperature electrolysis (HTE) for steady-state operation and economic viability was demonstrated for 10 MWth to 20 MWth microreactors. The NGR based system demonstrated a netback against estimated costs for a between first-of-a-kind and nth-of-a-kind (BOAK) reactor in 8 years but required a carbon tax exceeding $75.6/tonneCO2 to be competitive with existing ammonia production plants. The HTE based system meanwhile achieved a netback in 18 years and its competitiveness with renewable electricity-based ammonia production depended on the assumptions around electricity costs. When more moderate ammonia market prices were considered, the NGR based system required 17 years to achieve a netback while the HTE system was unable to do so in the studied pay off period of 25 years.