Conceptual design of ammonia‐based energy storage system: System design and time‐invariant performance

Abstract

in Wiley Online Library (wileyonlinelibrary.com)Chemicals-based energy storage is promising for integrating intermittent renewables on the utility scale. High roundtrip efficiency, low cost, and considerable flexibility are desirable. To this end, an ammonia-based energy storage system is proposed. It utilizes a pressurized reversible solid-oxide fuel cell for power conversion, coupled with external ammonia synthesis and decomposition processes and a steam power cycle. A coupled refrigeration cycle is utilized to recycle nitrogen completely. Pure oxygen, produced as a side-product in electrochemical water splitting, is used to drive the fuel cell. A first-principle process model extended by detailed cost calculation is used for process optimization. In this work, the performance of a 100 MW system under time-invariant operation is studied. The system can achieve a roundtrip efficiency as high as 72%. The lowest levelized cost of delivered energy is obtained at 0.24 $/kWh, which is comparable to that of pumped hydro and compressed air energy storage systems.All cost data except that for the ammonia-based energy storage system are reproduced from Rastler. 8 [Color figure can be viewed at wileyonlinelibrary.com] 1 Stage number of the turbines [E-30/37,RE-5/7] Re HX 5000 Reynolds number of the main streams of all heat exchangers DV, decision variable; CP, calculated parameter; SP, specified parameter; SV, specified value.

Modeling and Optimal Design of Absorbent Enhanced Ammonia Synthesis

“…A finite and depleting supply of fossil resources, as well as a desire for increased sustainability of fertilizer production have motivated the idea of producing ammonia using renewable energy. Additionally, ammonia has the potential as an energy-dense, carbon neutral liquid fuel, which, when made using renewables, could be used in various applications such as long-term energy storage or transportation to further reduce carbon intensity [4,5]. A proposed production pathway for renewable ammonia is to use electricity generated from renewable sources such as wind or solar to obtain hydrogen from electrolysis, nitrogen from air and to power the ammonia synthesis process itself.…”

Renewable production of ammonia and nitric acid

“…As shown in Figure a, an ammonia production process is obtained from modification of the closed‐loop ammonia‐based energy storage process from our previous work . In the following, we will denote this as the standard concept .…”

“…Reese et al show technical feasibility of a lab‐scale Haber‐Bosch process driven by intermittent wind power. Millet, Petipas et al and Mougin investigate transient operability of electrolyzers, such as proton exchange membrane (PEM) electrolyzer and solid oxide electrolyzer (SOE), and report no additional degradation on the stack level; (b) on the process level, we propose an ammonia‐based energy storage process involving the usage of a reversible high‐temperature solid‐oxide fuel cell. Chen et al present a novel design of an ammonia synthesis system for a solar thermochemical energy storage system.…”

“…Investigation on heat integration of renewable ammonia production is rare. Our previous work shows that conducting heat integration between a Haber‐Bosch process and a high‐temperature SOE drastically enhances efficiency. Furthermore, few publications consider process dynamics and their influence on design, especially when intermittent renewables are considered as feeds.…”

Co‐generation of Ammonia and H2 from H2O Vapor and N2 Using a Membrane Electrode Assembly

“…Around 80 % of the produced NH 3 is converted to be used as fertilizer. Recently, Wang et al proposed an ammonia‐based energy storage system . NH 3 may also become an important intermediate chemical for energy and indirect H 2 storage , .…”