To understand the driving change behind the types of fuel used in shipping, particularly for modern container ships, we need to understand a little of the history behind the shipping industry.
It wasn't until the beginning of the 19th century that cargo ships, which used sails to harness wind energy, began to be phased out in preference to steamships.
Towards halfway through the 20th century, motor ships using internal combustion engines took over, with their use favored in all large vessels, including container ships.
By the 1950s, Marine Heavy Fuel (MFO) had become popular due to the introduction of high alkaline cylinder lubrication, which neutralized acids generated by the high sulfur content of the heavy fuel oil.
Today, 98% of the world's fleet runs on heavy fuel oil. Large container ships can consume more than 63,000 gallons of marine fuel per day when running at top speeds. Naturally, environmentalists, scientists, and politicians are concerned about the impact on the environment.
While transporting goods by sea is estimated to only produce 75kg of carbon dioxide (CO2) emissions per ton of freight, compared to 3300kg per ton carried by plane for the same distance. However, heavy fuel also emits significant amounts of sulfur. So, is there a better solution?
The International Maritime Organization's mission
In response to the Paris Climate Accord, the International Maritime Organization (IMO) has set ambitious goals of halving all greenhouse gas emissions by 2050 (Compared to 2008) and carbon dioxide emissions by 40% by 2030, with a further target of 70% by 2050.
The Rise of Liquified Natural Gas Fuel
Liquified Natural Gas (LNG) is chemically very close to the natural gas currently used in homes and industry. LNG is almost entirely free of sulfur due to its production process. Although it is not a complete solution to the carbon dioxide target, it does emit significantly less CO2. In combination with carbon capture technologies, both present and future, LNG has proven to be the biggest contender for rapid change in the shipping industry.
Of course, converting vessels with a 20–30-year lifespan over to alternative technologies is a significant investment. While other technologies exist that could step into the role soon to be vacated by MFO, companies are hesitant to make changes that might prove to be wrong in terms of competitiveness and longevity. For this reason, significantly fewer organizations are considering biofuels, electricity, hydrogen fuel cells, or ammonia as alternatives. LNG has come out on top, with 60% of shipping operators planning to use LNG or Liquid Petroleum Gas (LPG) in the next five years.
Converting to LNG
There are already many companies, such as MAN Energy Solutions, that promote and facilitate the conversion of vessels to LNG. These vessels can be retrofitted with state-of-the-art environmentally friendly engines, capable of maintaining the same speed and duration of journey for enormous container ships, with significantly lower sulfur, soot, and carbon dioxide.
The world's longest container ship powered by LNG is the CMA CGM Jacques Saadé, launched in September 2019 at 399.9 meters long and carrying up to 23,112 twenty-foot long containers.
A long way to go
However, more will need to change to hit the IMO targets. Although LNG is significantly more environmentally friendly than heavy fuel, with 90% less soot and virtually no sulfur, it only produces 18% less carbon dioxide.
It's likely that as we see the last of the HFO powered vessels finally being decommissioned or converted, LNG will already be giving way to newer, cleaner technologies as they become established.