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dc.contributor.advisorBrodal, Eivind
dc.contributor.authorJackson, Steven
dc.date.accessioned2021-11-22T22:08:32Z
dc.date.available2021-11-22T22:08:32Z
dc.date.issued2021-12-10
dc.description.abstractTo avoid the worst impacts of climate change a rapid green energy transition is required where traditional fossil fuels are replaced by low-carbon alternatives. One attractive route to emissions reduction is blue hydrogen, which has lower CO<sub>2</sub> emissions that traditional hydrogen production. For hydrocarbon exporters, increased blue hydrocarbon production can be achieved in two main ways: continued gas export with end-user-based hydrogen production or in-country hydrogen production and export. The cold climate in Norway provides a particular advantage to the performance of some industrial processes. A good example of this being the LNG plant at Melkøya, which is the most efficient of its type. Several other processes associated with blue hydrogen production could also benefit from low ambient temperature, increasing the attractiveness of in-country hydrogen production and potentially better supporting a future green hydrogen economy. The work summarised in this thesis includes a set of process optimization studies that look at the impact of ambient temperature on performance for several key links in the blue hydrogen supply chain. Along with this, a supply chain model is developed for a scenario where hydrogen is supplied from northern Norway to the UK. The focus of the work is process modelling and optimization, and several new sets of performance data are developed for important industrial processes. The main conclusion of this study is that the advantage offered by low ambient temperature in northern Norway is sufficient to make the export of blue hydrogen more efficient that a conventional LNG export based scenario over a range of realistic operating cases. The implication of this is that the basis for projects based on a conventional approach should be considered in more detail to ensure that they are based on a sound footing.en_US
dc.description.doctoraltypeph.d.en_US
dc.description.popularabstractIt is now obvious to many that to avoid the worst impacts of climate change a rapid green energy transition is required. This transition will involve the replacement of traditional fossil fuels with low-carbon alternatives such as hydrogen. Hydrogen can be used to supply heat and generate electrical power; it can be used as a transport fuel, and it can be used as an alternative to a fossil fuel feedstock in several important industrial processes. When renewable energy is generated in a remote location, or when it is available intermittently, hydrogen can also act as an energy storage medium. Because of these useful advantages the demand for hydrogen is set to grow with the. The recent EU Hydrogen Energy Roadmap , for example, estimates a seven-fold increase in the in Europe by 2050. When renewable energy is used to produce hydrogen using is produced via electrolysis using renewable energy, it is referred to as green hydrogen because the manufacturing process results in very low CO2 emissions. However, in most likely near future scenarios, total renewable energy supply will not meet total energy demand, putting large scale green hydrogen production in competition with other renewable energy consumers. Most currently produced hydrogen—often referred to as grey hydrogen—is derived from fossil fuels with associated CO2 emissions released. However, these emissions can be captured and transported to a storage site using a set of technologies referred to as Carbon Capture and Storage, CCS. Hydrogen produced in this way is called blue hydrogen. Although the overall level of greenhouse gas emissions avoided by blue hydrogen production is debated, its role in meeting emissions targets is still assumed by many to be important. The recently released UK hydrogen strategy, for example, is based around a ‘twin-track’ approach utilizing both blue and green hydrogen. For natural gas exporters, such as Norway, increased production of blue hydrogen offers an attractive pathway for emissions reduction, but choices remain on how this is best realized. One approach, that could be called conventional, is to maintain the existing approach to natural gas supply and generate hydrogen at the point of demand. The main alternative is to generate hydrogen where fossil fuels are first produced, with subsequent export in re-purposed natural gas pipelines or in tanker ships as a liquid. A disadvantage associated with the latter option is that the liquefaction of hydrogen consumes a large amount of energy, which represents a significant drawback for the development of ship-based supply chains. Seawater temperature along the coast of northern Norway is often 5 °C cooler than in southern Norway and 10 °C cooler than EU counties bordering the North Sea. Access to a low temperature cooling medium has benefits for many industrial processes that is well illustrated in the high efficiency achieved by the Snøhvit Liquefied Natural Gas, LNG, plant. This inherent advantage of cold climates has a potential impact on several elements the blue hydrogen supply chains that could link Norway to end-users in the Europe. In particular, the energy consumption associated with the liquefaction of hydrogen and the energy required for CO2 transportation are affected by ambient temperature. The aim of the research work presented in this thesis is, then, to study how the cumulative impact of low ambient temperature on elements in a blue hydrogen supply chain linking northern Norway to the UK could affect the relative efficiency of two specific supply scenarios: one where LNG is shipped from northern Norway and hydrogen is produced in the UK; the second, where hydrogen is produced in northern Norway, liquified and shipped to the UK. The method used in the this research work is to conduct a set of detailed process modelling studies for all of the links in the blue hydrogen supply chains where ambient temperature is expected to significantly affect performance. The individual performance studies are based on the optimization of process operating parameters at different cooling temperature cases. Common system design parameters are carried throughout each of the different parts of the modelling work to ensure a consistency in approach. In the latter part of the work, the results of each optimization study are combined into a system model for the two blue hydrogen supply chain alternatives identified earlier. Sensitivity studies are conducted where there exists significant uncertainty in the modelling parameters, and this is used to better understand the results. The results from the individual optimization studies highlight the important role that ambient temperature plays in the performance of several industrial processes. For example, when ambient temperature is reduced from 30 °C to 20 °C, the energy consumption of an LNG process is found to improve by around 10%, that of CO2 compression by around 8% and that of hydrogen liquefaction by around 5%. The results of the modelling work for the CO2 transportation process show that the impact of ambient temperature can be more significant that other aspects of the system design such as pipeline length and storage reservoir location. The results from the modelling of blue hydrogen supply chains shows that that the efficiency of the Norway based production scenario is always higher than the conventional scenario, which is based on LNG export, if more than 75% of the hydrogen product is required as liquid by the end user. Sensitivity studies also show that the trade-off fraction for liquids supply could be as low as 30% and that ambient temperature plays a significant role in the performance of the Norway based production scenario. The main conclusion of this work is that the advantage offered by low ambient temperature in northern Norway is sufficient to make the supply of blue hydrogen from northern Norway more efficient that a conventional supply scenario based on LNG export in a range of cases. The implication of this is that the basis for projects based on a conventional approach should be considered in more detail to ensure that they are based on a sound footing.en_US
dc.identifier.isbn978-82-7823-233-0
dc.identifier.isbn978-82-7823-234-7
dc.identifier.urihttps://hdl.handle.net/10037/23115
dc.language.isoengen_US
dc.publisherUiT Norges arktiske universiteten_US
dc.publisherUiT The Arctic University of Norwayen_US
dc.relation.haspart<p>Paper 1: Jackson, S., Eiksund, O. & Brodal, E. (2017). Impact of Ambient Temperature on LNG Liquefaction Process Performance: Energy Efficiency and CO<sub>2</sub> Emissions in Cold Climates. <i>Industrial & Engineering Chemistry Research, 56</i>(12), 3388 - 3398. Also available at <a href=https://doi.org/10.1021/acs.iecr.7b00333>https://doi.org/10.1021/acs.iecr.7b00333</a>. <p>Paper 2: Jackson, S. & Brodal, E. (2019). Optimization of the Energy Consumption of a Carbon Capture and Sequestration Related Carbon Dioxide Compression Processes. <i>Energies, 12</i>(9), 1603. Also available in Munin at <a href=https://hdl.handle.net/10037/15645>https://hdl.handle.net/10037/15645</a>. <p>Paper 3: Jackson, S. & Brodal, E. (2021). Optimization of a Mixed Refrigerant Based H<sub>2</sub> Liquefaction Pre-Cooling Process & Estimate of Liquefaction Performance with Varying Ambient Temperature. <i>Energies, 14</i>(19), 6090. Also available in Munin at <a href=https://hdl.handle.net/10037/23104>https://hdl.handle.net/10037/23104</a>. <p>Paper 4: Jackson, S. (2020). Development of a Model for the Estimation of the Energy Consumption Associated with the Transportation of CO<sub>2</sub> in Pipelines. <i>Energies, 13</i>(10), 2427. Also available in Munin at <a href=https://hdl.handle.net/10037/18325>https://hdl.handle.net/10037/18325</a>. <p>Paper 5: Jackson, S. (2020). Sensitivity Analysis and Case Studies for CO<sub>2</sub> Transportation Energy Consumption. <i>Proceedings of the 61st SIMS Conference on Simulation and Modelling SIMS 2020, September 22-24, Virtual Conference, Finland. Linköping Electronic Conference Proceedings, 176</i>(36), 257-263. Also available in Munin at <a href=https://hdl.handle.net/10037/20684>https://hdl.handle.net/10037/20684</a>. <p>Paper 6: Jackson, S. & Brodal, E. Case Studies into Low-Carbon derived Hydrogen Energy Supply to the UK from Norway. (Manuscript).en_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2021 The Author(s)
dc.subject.courseIDDOKTOR-008
dc.subjectChemical engineering: 560::Chemical process engineering: 562en_US
dc.titleThe Impact of Ambient Temperature on Low Carbon Energy Supply - Modelling and optimization studies on the supply of hydrogen energy from northern Norwayen_US
dc.typeDoctoral thesisen_US
dc.typeDoktorgradsavhandlingen_US


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