Saudi Arabia can produce green aviation fuel for the world by taking CO2 from the air
Saudi Arabia has huge reserves of oil under the ground, but it also has a huge resource of solar energy and huge areas of desert above it. My calculations show that 320 square kilometers of Photovoltaic cells in this nation can produce the energy required to meet the demand for all of the world’s aviation fuel. 320 square kilometers amounts to 0.017% of the land area of Saudi Arabia.
The technologies required involve the production of methane (CH4) from CO2 and water (the Sebatier process), and the process of converting methane into liquid fuels, with further CO2 capture, according to the processes researched by the Carbon Engineering Group.
Given the abundance of solar energy in Saudi Arabia and the vast areas of desert, this nation is a wonderful candidate for leveraging this technology for a greener future. Unbeknownst to many, Saudi Arabia has the cheapest per unit cost of solar energy production in the world.
The prospect of huge solar farms in the desert also have the added benefit of cooling the local climate around these solar farms, by converting a portion of the sun’s energy into electricity and then liquid fuel for export.
Here are my workings
To Make the Liquid Fuel from CO2, Gas and Electricity
To capture 1 tonne of CO2 and turn it into liquid fuel, 5.25GJ of methane is required, and 366kWh of electricity.
Assuming 90% energy efficiency, this results in [5.25+(366*0.0036)] * 0.90 = 5.91GJ of oil
5.91GJ of oil produced
…from 5.25GJ of methane
…and 366kWh of electricity
To Make Gas from CO2, Water and Electricity
To make 5.25GJ of methane, using the Sebatier process, with 95% efficiency, 5.25*278/0.95 = 1536kWh of electricity is required.
Given that CO2 + 2H2O => CH4 + 2O2
… which means 2.75 tonnes of CO2 is required for every tonne of CH4 produced
… and 1 tonne of methane is equivalent to 41.9GJ of gas
…the process removes 2.75/41.9=0.0656 tonnes of CO2 for every GJ of methane produced.
To make 5.25 GJ of methane,
… 0.0656*5.25=0.34 tonnes of CO2 is removed from the atmosphere,
… requiring 1536kWh of electricity
To Meet Electricity Demands for the Above
Therefore, 1536+366=1902kWh of electricity is required to remove 1+0.34=1.34 tonnes of CO2 from the atmosphere. 5.91GJ of liquid oil is produced in this process.
1902kWh of electricity input
… resulting 1.34 tonnes of CO2 removed
… producing 5.91GJ of liquid oil
The Demand for Airline Fuel
Global aviation fuel consumption annually in 2019 was 97 billion gallons
97 x 10^9 gallons = 12.7 x 10^9 GJ of oil required to meet world demand for aviation fuel
Solar Power Required in Saudi Arabia
To power the process using solar power in Saudi Arabia, note:
- solar irradiation averages 6.0kWh/m2 per day
- efficiency of PV cells at converting sun’s energy into electricity is about 20%
For each 1GJ of liquid oil production from air, 321.8 kWh of electricity is required
To produce 12.7 x 10^9 GJ of oil, 4,087 x 10^9 kWh of electricity is required.
Per day: 0.0348 x 10^9 GJ of oil, 11.2 x 10^9 kWh of electricity
To meet demand, (11.2×10^9 / (6.0*0.2)) = 0.37 x10^9 m2 of PV cells are required.
… or 370km2 of PV cells produces 12.7 billion GJ of oil
Total area of Saudi Arabia is 2,149,690 km2
Therefore, covering 0.017% of the ground in Saudi Arabia will produce enough energy to provide fuel for the entire aviation sector of the world.