By
Susan Parker |
The International Maritime Organization aims to cut the shipping sector’s overall greenhouse gas emissions by 50 per cent by 2050. In December 2019, Carnival Corporation joined the Getting to Zero Coalition as one of its many efforts to achieve the goal.
“We wanted to work with others in the industry to learn from their achievements (and mistakes) and not to duplicate the efforts,” says Tom Strang, senior vice president of maritime affairs at Carnival Corporation. “What we are doing is looking at different fuels and technologies to push forward.”
Presently the corporation has nine LNG-powered ships on order. Two additional vessels, AIDA Cruises’ AIDAnova and Costa Cruises’ Costa Smeralda, are already running on LNG 98 per cent of the time. While LNG is not a carbon-neutral fuel, Strang says it has a good infrastructure and can reduce the carbon footprint by up to 30 per cent depending on the type of technology used. LNG also virtually eliminates sulphur, decreases particulate matter by 95-100 per cent and significantly reduces nitrogen oxide emissions, providing a strong base from which Carnival can move forward.
Another of Carnival’s partnerships is the Pa-X-ell2 research project, which will develop fuel cells that are powered by hydrogen derived from methanol. This has the potential to supply power at even lower emissions than LNG. A pilot will be deployed on AIDAnova as early as 2021. “This is one of the first integrations of this type of technology,” says Strang. “There are very few ships at sea with fuel cells. It will be a significant size to prove the project.”
Being installed on AIDAperla this year is a first-of-kind lithium ion battery power system capable of generating an output of 10 megawatts. “We’re striving ahead so we can operate in port as close to zero as possible,” comments Strang. “You could use the batteries to manoeuvre in and out of port, or for around two hours alongside. It might also allow for an engine to run at optimum power during operations without needing an extra generator, again saving energy and reducing emissions.”
Different fuel types, such as hydrogen, ammonia and biofuel, are also being investigated. However, there is very limited infrastructure to provide these fuels to ships. There are also problems with the toxicity and lack of bunkering support and regulations for ammonia, as well as the large space required for storing hydrogen (four times that of a conventional fuel) and the requirement to keep it at minus 253C (minus 423F).
Gas turbines could also make a comeback due to their better emissions signature. “The challenge is to get the right combination of sizes based on the different load profiles,” says Strang. “A large turbine is not efficient on low load. Gas turbines and diesel engines are both around 50 per cent efficient in transforming fuel to energy. A fuel cell at 60 per cent or 80 per cent efficiency offers a very different possibility. We could potentially replace the engine with a fuel cell and battery. We’re in an interesting space, which is why we’re partnering with others to jointly explore options.”
Looking at a decarbonised future, Strang says there are several options when it comes to power development – even nuclear power is technically feasible. “We’re faced with a larger dilemma: what is the decarbonised fuel of the future?” he says. “We’re trying to find the optimum pathway to success.”
Strang says that in every case: “There are a lot of challenges and regulatory uncertainty.” However, he notes that not so long ago, ships were unable to carry an LNG tank, but now AIDAnova is continuously running on LNG with very positive feedback.
As the industry grapples with new nitrogen and sulphur oxide emission restrictions and regulations, it is also facing a call for zero-emission ships. Strang accepts the challenge, but says: “We always need to be safe and reliable which is why we’re doing the projects to reduce emissions and find a way towards a fully sustainable cruise industry.”
This article was first published in the Spring/Summer 2020 issue of Cruise & Ferry Review. All information was correct at the time of printing, but may since have changed.
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