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18 pages, 2976 KiB

Open AccessArticle

Renewable Electricity Generation in Small Island Developing States: The Effect of Importing Ammonia

by Victor N. Sagel, Kevin H. R. Rouwenhorst and Jimmy A. Faria

Energies 2022, 15(9), 3374; https://doi.org/10.3390/en15093374 - 5 May 2022

Cited by 5 | Viewed by 2503

Abstract

Recently, we demonstrated for Curaçao that renewable electricity generation from wind combined with energy storage in the form of ammonia is competitive with imported fossil fuels, such as LNG, oil, and coal. In the current work, we have expanded the model by considering [...] Read more.

Recently, we demonstrated for Curaçao that renewable electricity generation from wind combined with energy storage in the form of ammonia is competitive with imported fossil fuels, such as LNG, oil, and coal. In the current work, we have expanded the model by considering imported green ammonia as an alternative to local electricity generation and storage. Local production of ammonia as an energy storage medium was compared with imported ammonia to make up the electricity produced from onshore wind, for Curaçao and Fiji’s largest island Viti Levu. Curaçao and Viti Levu have been selected as two interesting extremes with favorable and non-favorable wind conditions, respectively. Assuming a market price of 500 USD/t NH₃, it is found that importing ammonia is the most feasible solution for both islands, with a levelized cost of electricity (LCOE) of 0.11 USD/kWh for Curaçao and 0.37 USD/kWh for Viti Levu. This compares to 0.12 USD/kWh for Curaçao; however, for Viti Levu, this value increases to 1.10 USD/kWh for a completely islanded system based on onshore wind and imported ammonia. These islands represent two extreme cases in terms of wind load factor and load consistency, as Curaçao has a high and consistent wind load factor when compared to Viti Levu. Thus, the conclusions obtained for these locations are expected to be applicable for other small island developing states. Full article

(This article belongs to the Special Issue Ammonia as an Energy Carrier)

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13 pages, 2245 KiB

Open AccessArticle

Economic Evaluation of an Ammonia-Fueled Ammonia Carrier Depending on Methods of Ammonia Fuel Storage

by Youngkyun Seo and Seongjong Han

Energies 2021, 14(24), 8326; https://doi.org/10.3390/en14248326 - 10 Dec 2021

Cited by 17 | Viewed by 5362

Abstract

This study proposed two concepts for ammonia fuel storage for an ammonia-fueled ammonia carrier and evaluated these concepts in terms of economics. The first concept was to use ammonia in the cargo tank as fuel and the second concept was to install an [...] Read more.

This study proposed two concepts for ammonia fuel storage for an ammonia-fueled ammonia carrier and evaluated these concepts in terms of economics. The first concept was to use ammonia in the cargo tank as fuel and the second concept was to install an additional independent fuel tank in the vessel. When more fuel tanks were installed, there was no cargo loss. However, there were extra costs for fuel tanks. The target ship was an 84,000 m³ ammonia carrier (very large gas carrier, VLGC). It traveled from Kuwait to South Korea. The capacity of fuel tanks was 4170 m³, which is the required amount for the round trip. This study conducted an economic evaluation to compare the two proposed concepts. Profits were estimated based on sales and life cycle cost (LCC). Results showed that sales were USD 1223 million for the first concept and USD 1287 million for the second concept. Profits for the first and second concepts were USD 684.3 million and USD 739.5 million, respectively. The second concept showed a USD 53.1 million higher profit than the first concept. This means that the second concept, which installed additional independent fuel tanks was better than the first concept in terms of economics. Sensitivity analysis was performed to investigate the influence of given parameters on the results. When the ammonia fuel price was changed by ±25%, there was a 15% change in the profits and if the ammonia (transport) fee was changed by ±25%, there was a 45% change in the profits. The ammonia fuel price and ammonia (cargo) transport fee had a substantial influence on the business of ammonia carriers. Full article

(This article belongs to the Special Issue Ammonia as an Energy Carrier)

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21 pages, 3472 KiB

Open AccessArticle

Thermochemical Recuperation to Enable Efficient Ammonia-Diesel Dual-Fuel Combustion in a Compression Ignition Engine

by Seamus P. Kane and William F. Northrop

Energies 2021, 14(22), 7540; https://doi.org/10.3390/en14227540 - 11 Nov 2021

Cited by 26 | Viewed by 4392

Abstract

A thermochemical recuperation (TCR) reactor was developed and experimentally evaluated with the objective to improve dual-fuel diesel–ammonia compression ignition engines. The novel system simultaneously decomposed ammonia into a hydrogen-containing mixture to allow high diesel fuel replacement ratios and oxidized unburned ammonia emissions in [...] Read more.

A thermochemical recuperation (TCR) reactor was developed and experimentally evaluated with the objective to improve dual-fuel diesel–ammonia compression ignition engines. The novel system simultaneously decomposed ammonia into a hydrogen-containing mixture to allow high diesel fuel replacement ratios and oxidized unburned ammonia emissions in the exhaust, overcoming two key shortcomings of ammonia combustion in engines from the previous literature. In the experimental work, a multi-cylinder compression ignition engine was operated in dual-fuel mode using intake-fumigated ammonia and hydrogen mixtures as the secondary fuel. A full-scale catalytic TCR reactor was constructed and generated the fuel used in the engine experiments. The results show that up to 55% of the total fuel energy was provided by ammonia on a lower heating value basis. Overall engine brake thermal efficiency increased for modes with a high exhaust temperature where ammonia decomposition conversion in the TCR reactor was high but decreased for all other modes due to poor combustion efficiency. Hydrocarbon and soot emissions were shown to increase with the replacement ratio for all modes due to lower combustion temperatures and in-cylinder oxidation processes in the late part of heat release. Engine-out oxides of nitrogen (NO_x) emissions decreased with increasing diesel replacement levels for all engine modes. A higher concentration of unburned ammonia was measured in the exhaust with increasing replacement ratios. This unburned ammonia predominantly oxidized to NO_x species over the oxidation catalyst used within the TCR reactor. Ammonia substitution thus increased post-TCR reactor ammonia and NO_x emissions in this work. The results show, however, that engine-out NH₃-to-NO_x ratios were suitable for passive selective catalytic reduction, thus demonstrating that both ammonia and NO_x from the engine could be readily converted to N₂ if the appropriate catalyst were used in the TCR reactor. Full article

(This article belongs to the Special Issue Ammonia as an Energy Carrier)

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14 pages, 849 KiB

Open AccessArticle

Public Attitudes and Concerns about Ammonia as an Energy Vector

by Andrea Guati-Rojo, Christina Demski, Wouter Poortinga and Agustin Valera-Medina

Energies 2021, 14(21), 7296; https://doi.org/10.3390/en14217296 - 4 Nov 2021

Cited by 6 | Viewed by 3065

Abstract

Ammonia is gaining popularity around the world due to its advantages as an energy vector over other zero-carbon fuels and has the potential to be a key component for deep decarbonisation of energy systems. However, little is known about public attitudes and concerns [...] Read more.

Ammonia is gaining popularity around the world due to its advantages as an energy vector over other zero-carbon fuels and has the potential to be a key component for deep decarbonisation of energy systems. However, little is known about public attitudes and concerns about the technology, one of the factors that will determine its successful implementation. This research examined public perception of green ammonia technologies through online surveys conducted in Mexico (n = 563) and the UK (n = 357). The results suggest that most of the participants in the two countries support the development of these technologies, with men being more likely to show support than women. Participants in Mexico and the UK had both negative and neutral associations of ammonia as a chemical, but overall perceptions of green ammonia were surprisingly positive. A multiple regression analysis indicates that support for this technology is highly dependent on the way participants perceive the benefits and the risks of implementing green ammonia as a fuel or for storage in their countries. Perceptions of green ammonia presented in this study must be interpreted cautiously because of the novelty of the concept. Therefore, additional research should be carried out to determine the positive opinion of green ammonia obtained in the research. Full article

(This article belongs to the Special Issue Ammonia as an Energy Carrier)

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20 pages, 38211 KiB

Open AccessArticle

Environmental Life Cycle Assessment of Ammonia-Based Electricity

by Andrea J. Boero, Kevin Kardux, Marina Kovaleva, Daniel A. Salas, Jacco Mooijer, Syed Mashruk, Michael Townsend, Kevin Rouwenhorst, Agustin Valera-Medina and Angel D. Ramirez

Energies 2021, 14(20), 6721; https://doi.org/10.3390/en14206721 - 15 Oct 2021

Cited by 26 | Viewed by 9000

Abstract

In recent years, several researchers have studied the potential use of ammonia (NH₃) as an energy vector, focused on the techno-economic advantages and challenges for full global deployment. The use of ammonia as fuel is seen as a strategy to support [...] Read more.

In recent years, several researchers have studied the potential use of ammonia (NH₃) as an energy vector, focused on the techno-economic advantages and challenges for full global deployment. The use of ammonia as fuel is seen as a strategy to support decarbonization; however, to confirm the sustainability of the shift to ammonia as fuel in thermal engines, a study of the environmental profile is needed. This paper aims to assess the environmental life cycle impacts of ammonia-based electricity generated in a combined heat and power cycle for different ammonia production pathways. A cradle-to-gate assessment was developed for both ammonia production and ammonia-based electricity generation. The results show that electrolysis-based ammonia from renewable and nuclear energy have a better profile in terms of global warming potential (0.09–0.70 t CO₂-eq/t NH₃), fossil depletion potential (3.62–213.56 kg oil-eq/t NH₃), and ozone depletion potential (0.001–0.082 g CFC-11-eq/t NH₃). In addition, surplus heat for district or industrial applications offsets some of the environmental burden, such as a more than 29% reduction in carbon footprint. In general, ammonia-based combined heat and power production presents a favorable environmental profile, for example, the carbon footprint ranges from −0.480 to 0.003 kg CO₂-eq/kWh. Full article

(This article belongs to the Special Issue Ammonia as an Energy Carrier)

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13 pages, 4005 KiB

Open AccessFeature PaperArticle

Methane/Ammonia Radical Formation during High Temperature Reactions in Swirl Burners

by Marco Osvaldo Vigueras-Zúñiga, Maria Elena Tejeda-del-Cueto, Syed Mashruk, Marina Kovaleva, Cesar Leonardo Ordóñez-Romero and Agustin Valera-Medina

Energies 2021, 14(20), 6624; https://doi.org/10.3390/en14206624 - 14 Oct 2021

Cited by 23 | Viewed by 3057

Abstract

Recent studies have demonstrated that ammonia is an emerging energy vector for the distribution of hydrogen from stranded sources. However, there are still many unknown parameters that need to be understood before ammonia can be a substantial substitute in fuelling current power generation [...] Read more.

Recent studies have demonstrated that ammonia is an emerging energy vector for the distribution of hydrogen from stranded sources. However, there are still many unknown parameters that need to be understood before ammonia can be a substantial substitute in fuelling current power generation systems. Therefore, current attempts have mainly utilised ammonia as a substitute for natural gas (mainly composed of methane) to mitigate the carbon footprint of the latter. Co-firing of ammonia/methane is likely to occur in the transition of replacing carbonaceous fuels with zero-carbo options. Hence, a better understanding of the combustion performance, flame features, and radical formation of ammonia/methane blends is required to address the challenges that these fuel combinations will bring. This study involves an experimental approach in combination with numerical modelling to elucidate the changes in radical formation across ammonia/methane flames at various concentrations. Radicals such as OH*, CH*, NH*, and NH₂* are characterised via chemiluminescence whilst OH, CH, NH, and NH₂ are described via RANS κ-ω SST complex chemistry modelling. The results show a clear progression of radicals across flames, with higher ammonia fraction blends showing flames with more retreated shape distribution of CH* and NH* radicals in combination with more spread distribution of OH*. Simultaneously, equivalence ratio is a key parameter in defining the flame features, especially for production of NH₂*. Since NH₂* distribution is dependent on the equivalence ratio, CFD modelling was conducted at a constant equivalence ratio to enable the comparison between different blends. The results denote the good qualitative resemblance between models and chemiluminescence experiments, whilst it was recognised that for ammonia/methane blends the combined use of OH, CH, and NH₂ radicals is essential for defining the heat release rate of these flames. Full article

(This article belongs to the Special Issue Ammonia as an Energy Carrier)

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13 pages, 2383 KiB

Open AccessArticle

Operating Limits for Ammonia Fuel Spark-Ignition Engine

by Christine Mounaïm-Rousselle, Pierre Bréquigny, Clément Dumand and Sébastien Houillé

Energies 2021, 14(14), 4141; https://doi.org/10.3390/en14144141 - 9 Jul 2021

Cited by 73 | Viewed by 5820

Abstract

The objective of this paper is to provide new data about the possibility of using ammonia as a carbon-free fuel in a spark-ignition engine. A current GDI PSA engine (Compression Ratio 10.5:1) was chosen in order to update the results available in the [...] Read more.

The objective of this paper is to provide new data about the possibility of using ammonia as a carbon-free fuel in a spark-ignition engine. A current GDI PSA engine (Compression Ratio 10.5:1) was chosen in order to update the results available in the literature mainly obtained in the CFR engine. Particular attention was paid to determine the lowest possible load limit when the engine is supplied with pure ammonia or a small amount of H₂, depending on engine speed, in order to highlight the limitation during cold start conditions. It can be concluded that this engine can run stably in most of these operating conditions with less than 10% H₂ (of the total fuel volume) added to NH₃. Measurements of exhaust pollutants, and in particular NOx, have made it possible to evaluate the possibility of diluting the intake gases and its limitation during combustion with pure H₂ under slightly supercharged conditions. In conclusion, the 10% dilution limit allows a reduction of up to 40% in NOx while guaranteeing stable operation. Full article

(This article belongs to the Special Issue Ammonia as an Energy Carrier)

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Review

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11 pages, 526 KiB

Open AccessReview

A Review of the Latest Trends in the Use of Green Ammonia as an Energy Carrier in Maritime Industry

by George Mallouppas, Constantina Ioannou and Elias Ar. Yfantis

Energies 2022, 15(4), 1453; https://doi.org/10.3390/en15041453 - 16 Feb 2022

Cited by 53 | Viewed by 12216

Abstract

This review paper examines the key barriers to using green ammonia as an alternative fuel in maritime industry. A literature survey is performed based on research articles and grey literature, with the aim of discussing the technoeconomic problems with and benefits of ammonia [...] Read more.

This review paper examines the key barriers to using green ammonia as an alternative fuel in maritime industry. A literature survey is performed based on research articles and grey literature, with the aim of discussing the technoeconomic problems with and benefits of ammonia and the relevant technologies. The limitations of ammonia as a maritime fuel and its supply chain, the expected percentage demand by 2030 and 2050, its economic performance compared to other shipping fuels such as hydrogen, and the current regulations that may impact ammonia as a maritime fuel are discussed. There are several key barriers to ammonia’s wide adoption: (1) High production costs, due to the high capital costs associated with ammonia’s supply chain; (2) availability, specifically the limited geographical locations available for ammonia bunkering; (3) the challenge of ramping up current ammonia production; and (4) the development of ammonia-specific regulations addressing issues such as toxicity, safety, and storage. The general challenges involved with blue ammonia are the large energy penalty and associated operational costs, and a lack of technical expertise on its use. Regardless of the origin, for ammonia to be truly zero-carbon its whole lifecycle must be considered—a key challenge that will aid in the debate about whether ammonia holds promise as a zero-carbon maritime fuel. Full article

(This article belongs to the Special Issue Ammonia as an Energy Carrier)

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