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

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

2023 Roadmap on ammonia as a carbon-free fuel

The 15 short chapters that form this 2023 ammonia-for-energy roadmap provide a comprehensive assessment of the current worldwide ammonia landscape and the future opportunities and associated challenges facing the use of ammonia, not only in the part that it can play in terms of the future displacement of fossil-fuel reserves towards massive, long-term, carbon-free energy storage and heat and power provision, but also in its broader holistic impacts that touch all three components of the future global food-water-energy nexus

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

Impact of grid connectivity on cost and location of green ammonia production: Australia as a case study

Green ammonia is a promising derivative of hydrogen with the capability to decarbonise the fertiliser and maritime industries, and to supplement clean energy supply in nations where renewable energy potential cannot satisfy demand. However, green ammonia production requires significant hydrogen and electricity storage infrastructure in order to convert variable renewable energy supply into a stable production process, which can meaningfully increase project costs. Here, we explore how a connection to the electricity grid may reduce these additional infrastructure costs. While previous authors have considered green ammonia plant optimisation without a grid connection (islanded production), or a grid connection with a fixed electricity price, this work considers the possibility of using both variable renewable energy and variably priced grid electricity for a large number of locations. Using Australia as a case study, we use a MILP model to optimise the production cost of green ammonia at a 1° spatial resolution, where the model can both buy and sell electricity from the grid if the connection costs are economically justified. The minimum Levelised Cost of Ammonia (LCOA) achievable when a grid connection is possible is almost 11% lower than if no grid connection is used, which amounts to savings of 2.5 USD GJ−1. Benefits from the grid are most significant in the state of Tasmania; although it does not have the cheapest power on average, it provides the best opportunity for green ammonia plants to exploit low prices when they occur. We demonstrate that where an ammonia plant is both a consumer from and supplier to the national electricity network, it is robust to price fluctuation in the grid. Although no Australian electricity market is yet decarbonised, only a small fraction of total power supply for green ammonia production (<15%) comes from the grid, meaning that production using a semi-islanded approach can still be considered green in most Australian locations; in some cases, where power is sold back to the grid, the emissions avoided from electricity sale may be larger than the emissions generated from electricity purchase

“Green” ammonia: Impact of renewable energy intermittency on plant sizing and levelized cost of ammonia

Ammonia production currently contributes almost 11% of global industrial carbon dioxide emissions, or 1.3% of global emissions. In the context of global emission targets and growing demand, decarbonization of this process is highly desirable. We present a method to calculate a first estimate for the optimum size of an ammonia production plant (at the process level), the required renewable energy (RE) supply, and the levelized cost of ammonia (LCOA) for islanded operation with a hydrogen buffer. A model was developed to quantitatively identify the key variables that impact the LCOA (relative to a ±10 GBP/tonne change in LCOA): levelized cost of electricity (±0.89 GBP/MWh), electrolyzer capital expenditure (±65 GBP/kW), minimum Haber–Bosch (HB) load (±12% of rated power), maximum rate of HB load ramping, and RE supply mix. Using 2025/2030 estimates results in a LCOA of 588 GBP/tonne for Lerwick, Scotland. The application of the model will facilitate and improve the production of carbon-free ammonia in the future

Formulating a policy package : what to start with? a new technique for the ranking of policy measures

A way forward to increase the success of policies which is increasingly discussed is the formulation of a policy package, rather than a combination of measures considered and deployed in isolation. Policy measures are the building blocks of policy packages and primary measures ‐ those policy measures that can directly affect the policy objectives – are the foundations of every package. In the process of formulating a policy package to address a certain policy problem, which is briefly discussed in this paper, an important step is deciding ‘what to start with’ given the range of primary measures available. This essentially involves a process of ranking the alternatives, commonly done using multi‐criteria decision making (MCDM) techniques. In this paper a new methodology for analysis and ranking of policy measures is introduced which combines network analysis and MCDM tools. This methodology not only considers the internal properties of the measures but also their interactions with other potential measures. Consideration of such interactions provides additional insights into the process of policy formulation and can help the domain experts and policymakers to better assess the policy measures and to understand the complexities involved. This new methodology is applied in this paper to the formulation of a policy to increase Walking and Cycling. The results demonstrate the advantages of such a method over the traditional MCDM ranking and the usefulness of the information provided by the policy measure network in the visualisation and analysis of the network structures. Such visualisation can clearly identify for policy makers the effects of the interaction between the measures and of their centrality on their likely effectiveness in influencing the policy targets or their (in)efficiency with respect to implementation and their dependence on other measures

Renewable methanol production: Understanding the interplay between storage sizing, renewable mix and dispatchable energy price

Chemical production using renewable energies is an important element on the roadmap of industry decarbonisation. This work investigates the optimisation of renewable power supply for a fully electrified methanol process, with a focus on the interplay between renewable fix, storage sizing and the use of backup dispatchable power source. The analysis is performed using the meteorological data obtained from two locations, i.e. Kramer Junction (US) and Norderney (Germany), which have excellent solar and wind source, respectively. The minimum levelised energy cost, which is optimised in terms of renewable power generation, renewable mix and storage size, is found to be 106USD/MWh and 103USD/MWh for operations in Kramer Junction and Norderney, respectively, based on a dispatchable energy price of 230USD/MWh. This leads to a levelised methanol cost of 1490USD/tonne and 1459USD/tonne with a respective renewable penetration of 81% and 96% in the production. The correlation between renewable penetration and dispatchable energy price in the most economical scenario exhibits a two-regime behaviour: the renewable penetration increases dramatically at the beginning and then slowly approaches 100% when the dispatchable energy price is above a critical point. For a fully renewable operation, the optimised levelised energy cost is found to increase to 167USD/MWh and 114USD/MWh for Kramer Junction and Norderney, respectively. The results show the importance of the dual functionality of hydrogen in the energy storage system, which improves the overall energy efficiency

“Green” ammonia: Impact of renewable energy intermittency on plant sizing and levelized cost of ammonia

Ammonia production currently contributes almost 11% of global industrial carbon dioxide emissions, or 1.3% of global emissions. In the context of global emission targets and growing demand, decarbonization of this process is highly desirable. We present a method to calculate a first estimate for the optimum size of an ammonia production plant (at the process level), the required renewable energy (RE) supply, and the levelized cost of ammonia (LCOA) for islanded operation with a hydrogen buffer. A model was developed to quantitatively identify the key variables that impact the LCOA (relative to a ±10 GBP/tonne change in LCOA): levelized cost of electricity (±0.89 GBP/MWh), electrolyzer capital expenditure (±65 GBP/kW), minimum Haber–Bosch (HB) load (±12% of rated power), maximum rate of HB load ramping, and RE supply mix. Using 2025/2030 estimates results in a LCOA of 588 GBP/tonne for Lerwick, Scotland. The application of the model will facilitate and improve the production of carbon-free ammonia in the future