The term “decarbonization” is a hot keyword in various industries, appearing daily in the news these days.
Companies around the world are making various efforts to reduce greenhouse gas (GHG) emissions such as Carbon Dioxide for the sake of the global environment. It is the same in the shipping industry.
The International Maritime Organization (IMO) has set a goal of reducing greenhouse gas emissions from ships by at least 50% by 2050.
In order to achieve this goal, the shipping industry is beginning to reconsider its use of marine fuels.
There are three steps in the IMO’s transition to decarbonization:
- Reduce GHG emissions by at least 40% by 2030
- Reduce GHG emissions by at least 50% by 2050
- Reduce GHG emissions to zero by the end of this century.
The goals are broken down into phases like this; therefore from the present year of 2021, there are practices to be implemented by 2030 as short-term goals and the one by 2050 as a mid-term goal.
Heavy oil is currently used as ship fuel. If you work in the logistics or shipping industry, you have probably heard of low-sulfur fuel oil, which became mandatory in January 2020.
The next generation fuels that are attracting particular attention are LNG (liquefied natural gas), ammonia, hydrogen, and more recently methanol.
It is not only the fuel that needs to be changed. As we switch to these fuels, it is also essential to change engines, fuel tank, and fuel supply infrastructures.
LNG is already in practical use as a marine fuel. It is set to reduce CO2 emissions by about 26%, Sulfur Oxides (SOx) by zero, and Nitrogen Oxides (NOx) by about 30%, compared to oil.
However, it is said that when LNG is burned in an engine, unburned methane (methane slip) leaks out. Unburned methane is about 25 times more potent, than CO2 as a greenhouse gas. It is also considered a problem that cows as livestock emit methane.
Since there are no regulations on unburned methane suppression yet, it is assumed that International Maritime Organization (IMO) will develop international standards related to methane slip in the future.
Ammonia has been used mainly as fertilizer, but in recent years, the use as a fuel has been attracting attention. Since ammonia for use as fertilizer is commonly distributed, the know-how for transportation and storage is well established. If you use ammonia, it reduces CO2 emissions to zero, but fuel engines to use ammonia have not yet been developed.
Technology is needed to burn ammonia efficiently, since it is difficult to burn. Also, measures are needed to prevent the generation of Nitrous Oxide (N2O), which has a greenhouse effect about 300 times greater than CO2.
In addition, the volume is 2.7 times larger than oil, so it needs larger fuel tanks and causes less space for transportation. This is an important point to look at as efficiency is very important in cargo transportation.
Also, ammonia itself is a toxic and corrosive hazardous material, so it is important to pay utmost attention to the safety while handling it.
Hydrogen fuel has been attracting a lot of attention in automobiles. Even if hydrogen is burned, it does not emit CO2 or SOx, but it does produce NOx, so technology is needed to suppress this.
Hydrogen, like ammonia, has not yet been developed as a fuel engine for ships. It needs to be cooled -253 degrees Celsius to store hydrogen as a liquid.
In addition, the volume is 4.5 times larger than oil, so the fuel tank must be large. And contrary to ammonia, hydrogen is very flammable and burns very fast, therefore high combustion control technology is needed. Additionally, the infrastructure for transportation and fuel supply is not in place as for now.
Methanol can be produced from natural gas, coal, and renewable energy. And it is said that when it burns, it reduces CO2 by 10%, SOx by zero, and NOx by 30%. As for the reduction of CO2, we cannot expect much effect, if the raw materials are made from natural gas, but if they are made from renewable energy, it effects significantly.
Just recently, Maersk, a major shipping company, has already ordered the industry’s first container feeder ship that uses methanol. In this sense, there’s a possibility that the introduction of methanol will proceed faster than ammonia and hydrogen.
Each fuel has its own characteristics and future technological development is also a major factor.
First of all, in order to achieve the short-term goal of 40% GHG reduction by 2030, shipping companies are now ordering LNG carriers.
As for ammonia and hydrogen, the future depends on technological development. Regarding hydrogen, so far we have succeeded in developing passenger ships using hydrogen fuel cells, but the adoption of hydrogen for cargo ships still has a long way to go.
While it is expected that LNG is the main fuel in the short to medium term, major companies have recently established or begun investing in companies that produces raw materials, ammonia, and methanol.
The battle for the leading role in the next generation of energy will certainly be interesting.