Various zero emission technologies for mitigating greenhouse gas emissions are being developed to limit the impact of climate change. Nuclear energy, fossil fuels with carbon capture and storage technology and renewable energy are major candidates for zero emission technologies. Hydrogen, which is considered in most global energy models as an energy carrier, is being actively developed but the specifics on its international transportation are yet to be clearly described.
In a recent paper published in International Journal of Hydrogen Energy, Yuki Ishimoto and colleagues at The Institute of Applied Energy studied the importance of hydrogen in both local and global energy systems as well as the amount of deployed carbon dioxide-free hydrogen, with special attention to the case of Japan.
A long-term intertemporal optimization energy model was used with the assumption that carbon dioxide-free hydrogen is produced in all regions and is transported to other regions around the globe. Projections of energy-related statistics were used to estimate the energy demand scenarios in the transportation, power and stationary sectors. The global energy structure of demand and supply was determined to reduce the costs of global energy systems while meeting the energy demand under constraints such as energy resources and carbon dioxide emissions. The simulation base year was 2010 and terminal year was 2050.
There is a rise in fossil fuel prices with time due to increase in primary energy and the associated consumption accumulation. Due to technological progress between the years 2020 and 2030, there is a decrease in hydrogen prices which increases after 2040, as a result of increase in the renewable energy share due to constraints of carbon dioxide emissions.
In the year 2050, the global hydrogen demand is about 621 Mtoe, with the transportation sector using the majority of the hydrogen share. Additionally, the world stock share of fuel cell vehicles is about 18% with their energy consumption share at 23%. The share of internal combustion engines decreases to about 2% due to the increase in use of biofuel and fuel cell trucks.
In Japan, due to severe carbon dioxide emission constraints towards 2050, there is an increase in power generation technologies with zero emissions. Power plants that are fired by natural gas gradually reduce the share of those fired by coal. Internal combustion engines are replaced with fuel cell vehicles, electric vehicles, and plug-in hybrid electric vehicles whose.
The authors compared indicators for both hydrogen and no-hydrogen cases and noted that the global energy system cost difference in the two cases was about 1% in 2050 which translates to about 200 billion USD. This shows an improvement in the energy system cost.
In both cases, the net carbon dioxide emissions in Japan are almost similar until 2040 after which there is a decrease in the hydrogen case. The research team noted that in the power sector, the carbon intensity drops to almost zero in 2050 which is improved due to hydrogen utilization. This results in a wide distribution of primary energy resources as well as the energy self-sufficiency ratio. A reduction in imports of natural gas and increased use of wind for electrolysis significantly improves this ratio. From this, it is observed that carbon dioxide-free hydrogen improves both local and global energy systems.
Yuki Ishimoto, Atsushi Kurosawa, Masaharu Sasakura, Ko Sakata. Significance of CO2-free hydrogen globally and for Japan using a long-term global energy system analysis. International Journal of Hydrogen Energy, 42, (2017), 13357-13367.Go To International Journal of Hydrogen Energy