An official website of the United States government
The storage of renewable energy is the major hurdle during the transition of fossil resources to renewables. A possible solution is to convert renewable electricity to chemical energy carriers such as hydrogen for storage. Herein, a highly efficient formate-piperidine-adduct (FPA) based hydrogen storage system was developed. This system has shown rapid reaction kinetics of both hydrogenation of piperidine-captured CO 2 and dehydrogenation of the FPA over a carbon-supported palladium nano-catalyst under mild operating conditions. Moreover, the FPA solution based hydrogen storage system is advantageous owing to the generation of high-purity hydrogen, which is free of carbon monoxide and ammonia. In situ ATR-FTIR characterization was performed in order to provide insight into the reaction mechanisms involved. By integrating this breakthrough hydrogen storage system with renewable hydrogen and polymer electrolyte membrane fuel cells (PEMFC), in-demand cost-effective rechargeable hydrogen batteries could be realized for renewable energy storage.
more »
« less
This content will become publicly available on January 1, 2027
Nonlinear predictive regulation of an integrated green hydrogen and ammonia production system under time-varying renewable energy supply
This work presents a comprehensive model for a modular system that integrates green hydrogen and ammonia production with renewable energy generation. The chemical module comprises a high-temperature water electrolyzer for hydrogen production and an ammonia synthesis reactor. When solving the models over time, the system exhibits complex yet predictable dynamics, with the chemical module having a much faster response than other components. Under typical weather conditions, the renewable energy module generates over 50 kW for most of the day, partially meeting the chemical module’s energy demands. Nonlinear model predictive control (NMPC) is employed to manage the operation of the chemical module in response to variable renewable energy availability. The proposed NMPC framework determines the optimal supplemental energy required from the conventional energy grid to sustain the process. When renewable energy availability is high, the controller minimizes grid energy usage, maintaining the chemical module near its desired operating conditions with minimal reliance on external sources. Conversely, during low renewable energy availability periods, the controller increases grid energy acquisition to ensure stable system operation, demonstrating a greater dependence on external energy supplies.
more »
« less
- Award ID(s):
- 2414683
- PAR ID:
- 10650004
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Computers & Chemical Engineering
- Volume:
- 204
- Issue:
- C
- ISSN:
- 0098-1354
- Page Range / eLocation ID:
- 109376
- Subject(s) / Keyword(s):
- Predictive modeling, Integrated systems, Green chemical production, Model predictive control, Renewable energy, Modular systems
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Affordable synthetic ammonia (NH3) enables the production of nearly half of the food we eat and is emerging as a renewable energy carrier. Sodium‐promoted chemical looping NH3synthesis at atmospheric pressure using manganese (Mn) is here demonstrated. The looping process may be advantageous when inexpensive renewable hydrogen from electrolysis is available. Avoiding the high pressure of the Haber‐Bosch process by chemical looping using earth‐abundant materials may reduce capital cost, facilitate intermittent operation, and allow operation in geographic areas where infrastructure is less sophisticated. At this early stage, the data suggest that 0.28 m3of a 50 % porosity solid Mn bed may suffice to produce 100 kg NH3per day by chemical looping, with abundant opportunities for improvement.more » « less
-
Most large-scale ammonia production typically relies on natural gas or coal, which causes harmful carbon pollution to enter the atmosphere. The viability of a small-scale “green” ammonia plant is investigated where renewable electricity is used to provide hydrogen and nitrogen via electrolysis and air liquefaction, respectively, to a Haber-Bosch system to synthesize ammonia. A green ammonia plant can serve as a demandresponsive load to the electricity distribution system and provide long-term energy storage through chemical energy storage in ammonia. A coordinated operational model of an electricity distribution system and an electricity-run ammonia plant is proposed in this paper. Case studies are performed on a modified PG&E 69-node electricity distribution system coupled with a small-scale ammonia plant. Results indicate the ammonia plant can adequately serve as a demand response resource and positively impact the distribution locational marginal price (DLMP).more » « less
-
Abstract The ability to withstand and recover from disruptions is essential for seaport energy systems, and in light of the growing push for decarbonization, incorporating clean energy sources has become increasingly imperative to ensure resilience. This paper proposes a resilience enhancement planning strategy for a seaport multi‐energy system that integrates various energy modalities and sources, including heating, cooling, hydrogen, solar, and wind power. The planning strategy aims to ensure the reliable operation of the system during contingency events, such as power outages, equipment failures, or extreme weather incidents. The proposed optimization model is designed as a mixed‐integer nonlinear programming formulation, in which McCormick inequalities and other linearization techniques are utilized to tackle the model nonlinearities. The model allocates fuel cell electric trucks (FCETs), renewable energy sources, hydrogen refueling stations, and remote control switches such that the system resilience is enhanced while incorporating natural‐gas‐powered combined cooling, heating, and power system to minimize the operation and unserved demand costs. The model considers various factors such as the availability of renewable energy sources, the demand for heating, cooling, electricity, and hydrogen, the operation of remote control switches to help system reconfiguration, the travel behaviour of FCETs, and the power output of FCETs via vehicle‐to‐grid interface. The numerical results demonstrate that the proposed strategy can significantly improve the resilience of the seaport multi‐energy system and reduce the risk of service disruptions during contingency scenarios.more » « less
-
Solid State Transformers (SSTs) are being considered as a replacement to the classic transformers especially for renewable energy and energy storage systems mainly due to their much smaller size and controllability and regulation over the transferred power. Multi-Port SSTs share one high frequency core for the isolation between several devices and hence are even more compact and efficient but the system is complex and the control of such a system is a challenge. This paper considers a four-port, MPSST connected to a renewable source, battery, load, and the grid and discusses various scenarios and operating points. It is shown that several factors including the ratio of the renewable power to the load, battery SOC status and role of the battery in the system change the desired power flow in the system and there are several control structure needed for each mode of operation. These modes of operation and the boundary between them are recognized and eventually a MIMO control scheme is suggested that includes several switches to changes the structure of the controller to adjust the controller structure to the operating condition. Eventually, input-output linearization technique has been adopted to the system to linearize the model and achieve a better control performance.more » « less
