New ocean mapping technology helps ships cut fuel use and CO₂ emissions

A UNSW academic’s innovative research uses ocean currents to optimize shipping routes and reduce the environmental impact of sea transport.

Each day more than 50,000 cargo ships ply the world’s oceans, carrying about 90% of all the goods that are traded worldwide.

Global shipping is an enormous industry—and it’s responsible for 3% of the world’s greenhouse gas emissions: if the shipping industry were a country, it would rank as the sixth-largest emitter of greenhouse gases.

To find more efficient routes for cargo ships, Associate Professor Shane Keating, a researcher in oceanography and applied mathematics at UNSW Sydney, has developed an algorithm using state-of-the-art ocean models and artificial intelligence (AI).

“With better ocean forecasts, ships can use the power of currents as they travel, reducing fuel use and cutting emissions,” says A/Prof. Keating.

His innovation will deliver ocean forecasts to the shipping industry under UNSW Sydney spinout company, CounterCurrent.

The company is built on 15 years of research studying ocean currents with a focus on forecasting, satellite remote sensing and data science.

“The algorithm is like a Google Maps for the sea, giving the most efficient route in real time based on the behavior of ocean eddies.”

Mapping the ocean

A/Prof. Keating is an expert in a type of ocean current called eddies, swirling circular currents that are the oceanic equivalent of atmospheric storms.

Eddies are found in every ocean basin and make up 90% of the kinetic energy of the ocean, but they aren’t well represented in existing ocean current forecasts.

By better incorporating ocean eddies in forecasts, Keating says that commercial ships can harness these currents to find more efficient routes across the ocean.

Most ships travel the shortest distance between two points on Earth’s surface. It’s known as a great circle route.

But that route, although it’s the shortest distance, is not the most fuel-efficient route because ocean currents are constantly moving the ship off that perfect geometrical line. The ship has to use its engines and therefore burn more fuel to stay on the line.

By going with ocean currents, ships will travel slightly longer distances over the surface of Earth, but they’ll travel more efficiently because they’re moving with ocean currents rather than against them.

You can do this in real time if you know where those ocean currents are.

Empowered by satellite images

One of the reasons this is possible is due to improved satellite technology, which now provides images that allow eddies to be tracked.

A/Prof. Keating began to look at how satellites could be used to measure the ocean from space after completing his doctoral degree in astrophysics at the University of California San Diego.

“In the past few decades, satellite technology has completely revolutionized the way we look at the ocean,” he says.

“Before the satellite era, our picture of the ocean was of a giant bathtub of seawater with just a few large ocean currents—like the Gulf Stream and the East Australian Current.

“Thanks to satellites, we now know that the ocean is highly turbulent and chaotic, like our atmosphere, and is filled with thousands of ocean eddies that can range in diameter from ten to 300 kilometers and depths of up to 2000 meters.”

Although eddies rotate slowly, with current speeds of up to two meters per second, the fact that seawater is 800 times denser than air means that each of these eddies has more momentum than a tropical cyclone.

Our view of ocean currents got a major upgrade in December 2022 with the launch of the Surface Water and Ocean Topography (SWOT) satellite.

SWOT is a joint US-French satellite mission capable of mapping ocean currents with 10 times the resolution of existing satellite technology.

A/Prof. Keating is a member of the international science team for the SWOT satellite and leads the Australian SWOT working group (AUSWOT), a consortium of researchers and stakeholders working to support the SWOT mission in the Asia-Pacific region.

To make the most of observations from satellites such as SWOT, researchers need to compare them with measurements taken at the surface.

In October 2023, A/Prof. Keating and a team of UNSW oceanographers boarded the state-of-the-art CSIRO research vessel RV Investigatorto gather essential ocean data under the satellite’s path as it orbits Earth.

Data collected from commercial vessels also plays an important part in helping improve our understanding of ocean currents and how they might be changing in a warming world.

In April 2024, A/Prof. Keating participated in a voyage on board a 140 meter-long cargo vessel traveling from the Port of Newcastle to Auckland, as part of the Ships of Opportunity Program (SOOP), a global partnership between the maritime industry and research scientists that uses commercial vessels to gather ocean observations for marine weather forecasts.

“It was amazing,” says A/Prof. Keating. “You are traveling across the ocean at the speed of a golf cart, so you can really see the impact of ocean currents on the vessel.”

Putting the puzzle together

A/Prof. Keating’s voyage onboard the cargo vessel gave him an inside look at a virtually invisible industry.

“Shipping is the lifeblood of the global economy, worth a staggering $20 trillion per year,” A/Prof. Keating says, “but we almost never hear about it unless something goes wrong.

“All of that shipping has a huge carbon footprint—over a billion tons of CO₂ equivalent per year is emitted by the shipping industry.”

The International Maritime Organization—the UN body that regulates the global shipping industry—has set a target of zero shipping emissions by 2050, with mandatory uptake of zero emission fuels such as green hydrogen and green methanol.

However, it will take time to replace the existing merchant vessel fleet with ships that can use alternative fuels, and, even then, these fuels will be 6–10 times more expensive than traditional bunker fuel.

A/Prof. Keating’s ship routing technology allows vessels to cut costs and emissions by making small adjustments to the ship’s route to take advantage of natural currents.

Having tested his technology on more than a hundred vessels, A/Prof. Keating has been able to demonstrate consistent fuel savings of up to 20%.

He is now engaging with several shipping companies and ship builders to commercialize the technology and make it accessible to the wider industry quickly.

“It’s a win-win for shipping companies,” says A/Prof. Keating. “They can save money and meet their emissions reductions targets right now, without any modification to the vessel or change in the vessel transit time.

“My hope is that, within the next five years, this research will change the way that ships cross the ocean so that shipping companies can meet their emissions targets.”