A global, spatially granular techno-economic analysis of offshore green ammonia production

Decarbonisation will see mass installation of wind turbines and solar panels to replace conventional energy systems. However, these renewables face two challenges: renewable energy production is intermittent, and land requirements are considerable. We propose a solution to both problems: production of green ammonia, a carbon-free fuel, in the ocean. Green ammonia can be produced from intermittent renewables, and can be dispatched as a hydrogen carrier, energy vector, shipping fuel, or decarbonised fertiliser. It is well suited to marine production — it benefits from the ocean's reliable wind resource, is easily transportable, can be stored cheaply under mild conditions, and only requires water, power and air for production. This article presents the first global heat map for ammonia production which considers ocean production, land availability restrictions, and transport to major demand centres. We show that, even considering the high costs of floating wind turbines, it is likely that cost savings will be realised by producing some of the global ammonia demand in the ocean (the precise fraction depends on the distribution of demand), predominantly because competition for land will limit onshore capacity in the best locations

MATHEMATICAL SIMULATION OF ADJACENT-COUPLING AMMONIA ABSORPTIVE REACTOR

The development of an efficient process for ammonia synthesis is a goal that has been long sought after; therefore, the application of an absorptive reactor for ammonia synthesis is important since it allows the reaction to occur under milder conditions. In the adjacent-coupling absorptive reactor, absorbent particles are positioned downstream the fixed ammonia synthesis catalyst bed. This kind of absorptive reactor leads to the enhanced conversion of ammonia synthesis under milder conditions, compared to the equivalent reactor used without absorbent. Here, we present the transient backflow cell model (BCM) to explain and analyse the phenomenon of absorption-enhanced reaction. The transient BCM, based on the first principle of mass balances, is developed to simulate that the backflow existing through the absorptive reactor. As a reference, the transient cell model (CM) is also implemented to simulate the absorptive reactor when assuming no existing backflow existing. These two models demonstrated that backflow through the absorptive reactor promotes the ammonia reaction conversion via two mechanisms: longer residence time for reaction and faster reaction rate due to the absorption of ammonia absorbed.The development of an efficient process for ammonia synthesis is a goal that has been long sought after; therefore, the application of an absorptive reactor for ammonia synthesis is important since it allows the reaction to occur under milder conditions. In the adjacent-coupling absorptive reactor, absorbent particles are positioned downstream the fixed ammonia synthesis catalyst bed. This kind of absorptive reactor leads to the enhanced conversion of ammonia synthesis under milder conditions, compared to the equivalent reactor used without absorbent. Here, we present the transient backflow cell model (BCM) to explain and analyse the phenomenon of absorption-enhanced reaction. The transient BCM, based on the first principle of mass balances, is developed to simulate that the backflow existing through the absorptive reactor. As a reference, the transient cell model (CM) is also implemented to simulate the absorptive reactor when assuming no existing backflow existing. These two models demonstrated that backflow through the absorptive reactor promotes the ammonia reaction conversion via two mechanisms: longer residence time for reaction and faster reaction rate due to the absorption of ammonia absorbed

Optimization of green ammonia distribution systems for intercontinental energy transport

Green ammonia is a promising hydrogen derivative which enables intercontinental transport of dispatchable renewable energy. This research describes the development of a model which optimizes a global green ammonia network, considering the costs of production, storage, and transport. In generating the model, we show economies of scale for green ammonia production are small beyond 1 million tonnes per annum (MMTPA), although benefits accrue up to a production rate of 10 MMTPA if a production facility is serviced by a new port or requires a long pipeline. The model demonstrates that optimal sites for ammonia production require not only an excellent renewable resource but also ample land from which energy can be harvested. Land limitations constrain project size in otherwise optimal locations and force production to more expensive sites. Comparison of current crude oil markets to future ammonia markets reveals a trend away from global supply hubs and toward demand centers serviced by regional production

Assessing the impact of climate change on the cost of production of green ammonia from offshore wind

Green ammonia has received significant interest as a zero-carbon energy vector. However, current techno-economic models used to estimate the cost of producing green ammonia only use historical weather datasets as their inputs. Climate change is beginning to have an observable impact on global weather systems, so it is therefore important to examine how resilient locations for green ammonia production will be to the effects of climate change on renewable energy resources. This work examines how the cost of producing green ammonia from offshore wind farms at four locations in the UK could change due to climate change. It uses the 1981–2000, 2021–2040 and 2061–2080 2.2km projections under the RCP8.5 scenario from the Met Office's UK Climate Projections 2018 dataset, which were bias corrected with reference to the ERA5 reanalysis dataset. Using an islanded green ammonia production model, the achievable levelised cost of ammonia (LCOA) was evaluated at four sites taken from confirmed projects in the UK's Offshore Wind Licensing Round 4, with the achievable LCOAs found to range between 935 and 1696 USD/t. Results from the three time periods were compared to assess the impact of climate change and were benchmarked against LCOAs from conventional production pathways. At all sites, increases of between 6% and 8% of the average LCOAs were observed for the 2021–2040 and 2061–2080 scenarios respectively, with the changes found to be statistically significant through application of a two tailed T-test with a confidence level of 5%

A Semantic Information Model for Capturing and Communicating Design Decisions

A semantic information model to improve reuse and communication of engineering design knowledge is presented in this paper. We consider design to be a process involving a sequence of decisions informed by the current state of information. As such, the information model developed is structured to reflect the conceptualizations of engineering design decisions with a particular emphasis on semantically capturing design rationale. Through the approach presented, knowledge reuse is achieved by communicating design rationale. A case study is presented to illustrate two key features of the approach: (1) seamless integration of separate modular domain ontologies and instance knowledge related to engineering design that are needed to support decision making and (2) the explicit documentation of design rationale through design decisions

An Experimental DUAL Model of Advanced Liver Damage

Individuals exhibiting an intermediate alcohol drinking pattern in conjunction with signs of metabolic risk present clinical features of both alcohol-associated and metabolic-associated fatty liver diseases. However, such combination remains an unexplored area of great interest, given the increasing number of patients affected. In the present study, we aimed to develop a preclinical DUAL (alcohol-associated liver disease plus metabolic-associated fatty liver disease) model in mice. C57BL/6 mice received 10% vol/vol alcohol in sweetened drinking water in combination with a Western diet for 10, 23, and 52 weeks (DUAL model). Animals fed with DUAL diet elicited a significant increase in body mass index accompanied by a pronounced hypertrophy of adipocytes, hypercholesterolemia, and hyperglycemia. Significant liver damage was characterized by elevated plasma alanine aminotransferase and lactate dehydrogenase levels, extensive hepatomegaly, hepatocyte enlargement, ballooning, steatosis, hepatic cell death, and compensatory proliferation. Notably, DUAL animals developed lobular inflammation and advanced hepatic fibrosis. Sequentially, bridging cirrhotic changes were frequently observed after 12 months. Bulk RNA-sequencing analysis indicated that dysregulated molecular pathways in DUAL mice were similar to those of patients with steatohepatitis. Conclusion: Our DUAL model is characterized by obesity, glucose intolerance, liver damage, prominent steatohepatitis and fibrosis, as well as inflammation and fibrosis in white adipose tissue. Altogether, the DUAL model mimics all histological, metabolic, and transcriptomic gene signatures of human advanced steatohepatitis, and therefore serves as a preclinical tool for the development of therapeutic targets.Supported by EXOHEP-CM (S2017/BMD-3727), Ramón y Cajal (RYC-2014-15242 and RYC-2015-17438), NanoLiver-CM (Y2018/NMT-4949), COST Action (CA17112), AMMF (2018/117), ERAB (EA 18/14), MINECO Retos (SAF2016-78711 and SAF2017-87919-R), and German Research Foundation (DFG NE 2128/2-1, SFB 1382-403224013/A02, and SFB/TRR57/P04). FJC is a Gilead Research Liver Scholar. The research group belongs to the validated Research group Ref. 970935 “Liver Pathophysiology”, 920631 “Lymphocyte immunology”, 920361 “Immunogenética e inmunología de las mucosas” and IBL-6 (imas12-associated). FG and KZ are Chinese Scholarship Council (CSC) fellows. O.E.-V is supported by Beca FPI (associated to MINECO SAF2017-87919R) and R.B.-U. by Contratos predoctorales de personal investigador en formación UCM-Banco Santander (CT63/19)