| dc.description.abstract | Population growth and the expansion of industries have increased energy demand. In addition, the use of fossil fuel as an energy source produces greenhouse gases and increases air pollution. As a result, countries are looking for alternatives to fossil fuel for energy production. Using hydrogen as fuel is one of the most important ways to reduce fossil fuel consumption. Hydrogen can be used not only as a fuel but also as an energy carrier for producing electricity. Therefore, it is essential to know how hydrogen is produced. Hydrogen can be produced from different ways. It can be produced by splitting water molecules in an electrolyser. About 2/3 of the earth is covered by water, and it can be good resource for electrolyzer. However, this process requires high-quality water. In January 2018, there were 184 offshore oil and gas rigs in the North Sea. More than 60% of wells in these rings are going to be plugged and abandoned within 15 years and therefore these rigs will must be decommissioned. However, rigs may be excellent places to produce hydrogen from seawater as well. Because of the role of these rigs in oil and gas production, pipes already exist for transporting hydrogen onshore from them. The hydrogen production process described in this thesis is based on an electrolyser with input flow rate of 300 l/hr. An economically optimal system for producing water with a conductivity in the range of 0.1–1 µS/cm with seawater as the input was designed in this study. The system was optimised by analysing 24 design cases using the WAVE (Water Application Value Engine) design software. The cost of producing hydrogen using the optimal system was then calculated. For the optimal system, the cost of hydrogen production was $3.51/kg H2. In addition, the best option for low-cost power production using renewable resources, e.g., photovoltaic (PV) devices, wind turbines, and electricity from the grid, was assessed, depending on the location of the case considered. Models were created using the HOMER Pro (Hybrid Optimization of Multiple Energy Resources) software to optimise microgrids and distributed energy resources, assuming a nominal discount rate, inflation rate, project lifetime, and CO2 tax. Eight different scenarios were examined using HOMER Pro. The main findings are as follows:
The cost for producing suitable water for electrolyser to compare with the cost of electricity for electrolyser has a low effect on the total cost for hydrogen production (less than 1%)
The optimal solution was shown to be electricity from grid is the lowest levelised cost of energy (COE) among those analysed. Its hydrogen production cost was about $ 5 /kg H2.
When new costs for CO2 emissions in Norway starting in 2025 were considered, grids still had the lowest hydrogen production cost: approximately $9.42/kg H2.
The wind was found to be more economical energy resource than solar. | |