WHY THIS MATTERS IN BRIEF
The world’s cargo ships use bunker fuel which is the most polluting form of all fuels, and they need to reach carbon zero by 2050. Ammonia could be the answer.
There’s a lot to like about ammonia. But its smell isn’t one of them. This colorless fuel emits no Carbon Dioxide when burned. It’s abundant and common, and it can be made using renewable electricity, water, and air. Both fuel cells and internal combustion engines, like the one for this next generation hypersonic aircraft, can use it, and unlike hydrogen it doesn’t have to be stored in high-pressure tanks or cryogenic dewars like the ones in the latest superyachts. Plus, it has 10 times the energy density of a Lithium-Ion battery.
For all these reasons, ammonia (NH3) is gaining favor in the global shipping industry, a multi trillion-dollar industry that’s slowly turning itself electric as it desperately searches for cleaner fuels to power the freighters and tankers that haul manufactured goods and bulk materials across the ocean.
Maritime shipping contributes nearly 3 percent of annual carbon-dioxide emissions, according to the International Maritime Organization (IMO), the United Nations body that regulates the industry. In 2018, delegates agreed to reduce emissions by 50 percent from 2008 levels by 2050. But, needless to say, meeting that target will require swift and widespread development of diesel-fuel alternatives and new designs for freighters, tankers, and container ships.
Shipowners and industry analysts say they expect ammonia to play a pivotal role in decarbonizing cargo ships. But there’s a crucial caveat: No vessels of any size today are equipped to use the fuel. Even if they were, the supply of renewable, or “green,” ammonia produced using carbon-neutral methods is virtually non-existent. Most ammonia is the product of a highly carbon-intensive process and is primarily used to make fertilizers and chemicals.
Recently, though, a handful of projects aim to change that. Finland’s Wärtsilä plans to begin testing ammonia in a marine combustion engine in Stord, Norway, by late May. Germany’s MAN Energy Solutions and Korean shipbuilder Samsung Heavy Industries are also part of an initiative to develop the first ammonia-fueled oil tanker by 2024, and by 2024, the Viking Energy, which will be chartered by Equinor and fuelled using green ammonia from chemicals giant Yara, is poised to become the first vessel propelled by ammonia fuel cells.
The initiative “will open up a completely new option for zero-emission shipping,” says Henriette Undrum, Equinor’s vice president of renewable and low-carbon technology. “We are not just solving one small problem for one ship. It’s part of the bigger picture. It will be a starting point to build up the market for zero-carbon fuels.”
Still, industry experts say that revamping the global shipping fleet will be extraordinarily expensive. Researchers estimate that up to US $1.4 trillion will be needed to achieve the IMO’s emissions-reduction target. And fully eliminating emissions will require an additional $500 billion, according to a January 2020 study by a panel of maritime experts.
A number of climate-friendly technologies are being considered to reach that goal, including fuel cells, hydrogen-storage systems, and large battery packs, the latter of which was recently trialled in China.
Spinning metal cylinders, towing kites, and other propulsion methods are already helping to curb diesel fuel consumption by harnessing the wind. But ammonia will likely dominate among ocean-crossing vessels, which sail for days or weeks between refuelling and rely on common infrastructure worldwide.
“For such ships ammonia is the lowest-cost zero-emission fuel that we could find,” says Tristan Smith, a researcher at University College London’s Energy Institute, which evaluated more than 30 different shipping fuels.
Smith predicts green ammonia, so called because it’s produced using electricity from renewable green sources, will be produced in large volumes and will start to be used on ships during the coming decade. Other researchers make similar predictions. According to a September 2019 report from the international consultancy DNV, ammonia could make up 25 percent of the maritime fuel mix by mid century, with nearly all newly built ships running on ammonia from 2044 onward.
For ammonia-fuelled shipping to become a reality, though, several things need to go right. Manufacturers and engineers must overcome key technical hurdles and safety issues in the design of ammonia engines and fuel cells.
Port operators and fuel suppliers must build vast “bunkering” infrastructure so ships can fill ammonia tanks wherever they dock. And energy companies and governments will need to invest heavily in solar, wind, and other renewable energy capacity to produce enough green ammonia for thousands of ships. Globally, ships consume an estimated 300 million tons of marine fuels every year. Given that ammonia’s energy density is half that of diesel, ammonia producers would need to provide twice as much liquid ammonia, and ships will need to accommodate larger storage tanks, potentially eating into valuable cargo space. But, if these efforts succeed, it will mark a dramatic revival for a transportation fuel that’s largely sat on the sidelines since World War II.