Container ships are the giants of world trade. Whether bananas, T-shirts or televisions most of our goods reach us by sea. But these huge ships leave a major environmental footprint.
Their stacks spew out masses of greenhouse gases. Can the shipping industry transition to green fuel before it's too late? It’s a cold January day in Berlin.
An unusual boat the Elektra is about to embark on an important test voyage from Berlin's big industrial harbor. It has taken Sebastian Apenbrink and his colleagues years to get to this day. Together, they have developed the world's first zero-emission towboat.
The ship’s motors don’t run on diesel, but on batteries and three hydrogen fuel cells. The team from Berlin’s Technical University is nervous. It's a new ship, a new system.
It’s all new so anything might happen. Maybe a fuel cell won’t start, or the hydrogen system will leak. Maybe an inverter will fail, and we can’t switch over to the batteries.
Anything could happen, and that makes me a bit nervous. I hope everything goes to plan tomorrow. If the Elektra doesn’t pass its certification test tomorrow, six years of work will have been in vain.
This is how the ship’s propulsion system works. Hydrogen stored in fuel cells reacts with oxygen which the ship takes in from the air generating electricity to power the motors. The only emission is clean water vapor.
It’s a milestone in the fight against climate change. A lot depends on tomorrow's test, and not just for the project team. Is the last test still running?
It’s done. I’m starting the fuel cell. The Elektra could become a model for the entire industry.
Most ships still run on marine diesel and heavy fuel oil, which negatively affect the climate. All in all, shipping consumes about 300 million tons of fuel per year. Shipping vessels release massive amounts of air pollutants and greenhouse gases into the environment, including one billion tons of CO2 per year.
That’s more than Germany’s total annual output. Thousands of these ships travel international routes each year. They have long been exempt from climate policy.
Because these ships are always traveling between countries and continents, it is difficult to attribute their emissions to individual nations. The International Maritime Organization, based in London, is responsible for regulating maritime transport. Its 176 member countries all have very different interests.
. . but in 2018, they did agree to the first joint climate target: a 50% reduction of CO2 emissions by 2050 from 2008 levels.
Climate activists called it irresponsible and took to the streets. They point to the fact that many countries aim to be climate-neutral by 2050. Countries don’t take responsibility for their own shipping emissions.
Everything falls between the lines. The amount that shipping emits is more than countries, it’s a vast amount, and what’s on the table at the moment will not work. It might come as a surprise that the push for increased climate action is coming from the ships’ owners, the shipping companies.
One of the largest is the Danish company Maersk. It wants to be CO2-neutral by 2050. Maersk has recruited biologist Jacob Sterling from the World Wildlife Fund to devise a corresponding strategy for its fleet.
Maersk and our ships alone, a bit over 700 ships, actually emit 0. 1% of the global CO2 emissions. So, one of every thousand tons of CO2 that is being emitted on this planet comes from one of our ships.
I think that's a massive responsibility that we need to do something about. But doing something would require building new types of ships. What should these vessels look like and what fuel should they use?
Building a container ship costs 100 million euros or more. A vessel normally has a life span of more than 20 years. Betting on the wrong technology would be a disaster.
But time is running out. Climate action and ecological responsibility are now key factors shaping many corporate strategies. Our direct customer behavior is changing.
Our investors are beginning to ask different questions about this and being much more serious about it. If we don’t act with speed on this as a company, we might become irrelevant. So far, shipping companies have focused on saving fuel through better ship design, because this also saves money.
An optimized bow shape reduces energy consumption by up to 8%. A streamlined hull can save up to 20%. And reducing speed also cuts fuel consumption significantly.
Harnessing the wind can also help save energy, an idea being pursued by Michael Vahs, a ship’s captain and university professor. He has rediscovered a sail system invented by German engineer Anton Flettner in the 1920s. Flettner placed rotating cylinders on the decks of ships.
Since diesel was cheap back then, his idea did not catch on. The Flettner rotor, essentially wind-assisted propulsion for ships, always re-emerges when fuel prices are high. This was the case in 2007 when Michael Vahs decided to develop a Flettner rotor for modern cargo ships at the Emden-Leer University of Applied Sciences.
He uses a model ship placed in a wind tunnel to test the rotating cylinder’s properties. He wants to know what type of surface is best and how big the cylinder should be. This is how the Flettner rotor system works: an integrated motor starts rotating the cylinder.
The cylinder draws air past it. When wind hits this air flow, it is carried along and accelerated on one side of the rotor and slowed down on the other side. This propels the ship forward.
The amount of propulsion depends on wind speed and direction as well as rotor speed. Since the weather at sea cannot be controlled, researchers are running tests to find the optimal rotor speed for different wind conditions. They’ve learned that faster isn’t better.
Rotor speed must be adapted to wind conditions. That was a bit of a breakthrough for us. We realized that you get a lot more out of a rotor when you control it well.
I think we were the first in the world to do that. Of course, others are now doing it, too, but I believe our research led the way. This is where Ralf Oltmanns comes in.
He studied with Michael Vahs years ago and has been a fan of the Flettner rotor ever since. He advises shipping companies on installing rotors on their vessels something that requires careful planning. We’ll reduce the diameter of the base, and then it can go through the focsle deck.
Installation would require several changes be made to the ship’s deck, but Oltmanns must convince the ship owner first. We’ll go up through the bridge, cut through the deck, and then into the wheelhouse. .
. Ralf Oltmanns is determined. I would like to see these rotors become standard equipment in the shipping sector, allowing it to become more sustainable.
I’d like to see that happen as soon as possible. Like, now. That's my dream.
But things move slowly in the shipping industry. Only a few ships have been equipped with rotors so far. Although ship owners are reluctant to invest in the technology, a few projects are now in the planning stage.
Higher energy prices and the need to reduce CO2 are making the investment worthwhile. That’s because a Flettner rotor can reduce fuel consumption by about 15%. But while improved propulsion systems like rotors as well as better ship design and piloting can greatly reduce CO2 emissions, studies show this won't be enough.
For shipping to become climate-neutral, the industry needs a new fuel. But what alternatives to diesel and heavy fuel oil are there? These days, there’s an especially good supply of liquefied natural gas or LNG.
It’s already used by German shipping company Hapag-Lloyd. While it’s still a fossil fuel, LNG produces less pollution. We are constantly looking at what is technically possible to reduce emissions.
LNG is widely available, the infrastructure exists, and regulations are in place. This means we can reduce emissions here and now. The world's first conversion of a container ship to liquefied natural gas propulsion occurred in 2020.
The seminal moment was the installation of the LNG tank a 13-hundred-ton receptacle placed into the belly of the ship by a floating crane. It’s precision work. An entire cargo hold had to make way for the new piece of equipment.
The conversion was a pilot project incorporating many custom-made components. Planning and installation took two years. These days, the Brussels Express transports containers between Asia and northern Europe.
Hapag-Lloyd has placed orders for more LNG-powered vessels, because gas has several advantages over heavy fuel oil and diesel. Above all, it cuts down the carbon footprint of these giants. Compared to diesel, burning LNG releases 80% fewer nitrogen oxides and about 20% less CO2.
But there’s a catch: some engines allow methane to escape a greenhouse gas that, measured over a century, is 30 times more harmful than CO2. Methane can also escape into the atmosphere during LNG production and transport. As a fuel, it’s not yet climate-neutral.
The goal is clearly to become climate-neutral, and we won’t achieve that with fossil fuels. LNG lets us reduce emissions, but it's only an interim solution. In the long term, we’ll need synthetic fuels.
And for that, a lot of green energy must be available, which is not yet the case. One such solution is green hydrogen as used on the Elektra towboat in Berlin. It’s about to undergo its certification test.
Whether the Elektra can become a model for the future of shipping depends on what the inspectors say. The ship’s hydrogen-powered engine must be able to deliver enough power. The Elektra's power system, a novel combination of batteries and fuel cells, is up and running.
No one has any experience with such a system, but everything will have to work right away. First, the team prepares for a speed test. The Elektra must reach 10 kilometers per hour.
Otherwise, it may hold up other ships. Right now, speed is definitely our biggest concern. The next question is whether we can travel as far as planned with the energy on board.
Can the Elektra reach 10 kilometers per hour? I was a bit nervous during the speed test at full throttle. We were all relieved when the speedometer showed 10.
2 kilometers per hour. We could have done more, but decided to pull back. On this part of the canal, the speed limit is 10 km/h anyway, and we didn’t want to take unnecessary risks.
With the first stage completed, the Elektra docks at a harbor in nearby Spandau. But that was just the start. A second 65-meter-long barge is lashed to the boat.
It looks empty but is loaded with many tons of ballast water. This will test the Elektra even further. So far, Sebastian Apenbrink and his university colleague are pleased with how things are going.
But more challenges lie ahead. The team is in uncharted waters. How will the boat perform pushing this huge barge?
It's 150 meters long. The team is heading towards Wannsee. The Elektra is now pushing a load of around 15 hundred tons.
Will the hydrogen and battery charge be enough? If all goes well, the Elektra will be pushing barges like this one from Berlin to Hamburg next year. The test run is over.
It was very interesting. It was my first time out on the ship, and it was really nice, quiet, like you’re just gliding along. The boat did well in all the tests.
It's great that everything worked so well, from the initial idea all the way to realization. It was a lot of work. Lots of blood, sweat and tears from many people.
But we have reached a huge milestone. Now we can carry on. Such pilot projects also interest Martin Cames from one of Germany’s largest ecological institutes.
For over 15 years, he has been working to advance a transition to green energy in shipping and has just written a study on alternative fuels. For him, hydrogen propulsion has both benefits and drawbacks. Hydrogen is certainly an option for shorter distances.
But to cross the Atlantic, we need other fuels. We're a bit skeptical as to whether hydrogen would be feasible. The hydrogen supply and batteries should allow the Elektra to travel about 400 kilometers on a single charge.
For ships traveling close to shore, that’s not an issue. But container ships spend many days crossing the Atlantic. They would need to store so much hydrogen for their trips, there would hardly be any room left for cargo.
On top of that, the batteries would have to be so big and heavy that the ship would sink. Two reasons hydrogen isn’t suitable for powering container ships. These vessels need a different climate-friendly fuel, one that performs well because these giants require massive amounts of energy.
The engines in their bowels are as big as houses. On an average day at sea, they burn 120 tons of fuel. That corresponds to the daily energy use of around 30 thousand households in Germany.
What’s more, all systems on board cargo ships are geared towards the use of diesel and heavy fuel oil. And their crews are only trained in using that type of engine. Another advantage of using fossil fuels: bunkering, or refueling, is possible at any time and almost anywhere in the world.
We've been used to basically using diesel for the last hundred years in shipping. Now we have a fairly short time frame to ramp out something completely different. But which fuel should it be?
Jacob Sterling and his colleagues agree that neither the production nor consumption of the new fuel should emit greenhouse gases. The team is considering hydrogen, ammonia and methanol. All three can be produced with green energy.
But they all have one major drawback. The green fuels that we believe are the future, green fuels, do not exist at scale today. I think our main challenge is that we need to build basically a completely new marine fuel industry from scratch.
Many experts believe that ammonia would be the most suitable. It is already mass-produced and can be easily transported and stored in tanks. Like here in Rostock.
Ammonia is not yet produced using green energy. But Angela Kruth and her colleague Jens Wartmann are convinced this can change. Both specialize in developing green technologies.
They are part of a larger team seeking to advance the production of green ammonia in north-east Germany. They hope the fuel can become a mainstay in commercial shipping. To that end, they founded Campfire, a research and business consortium.
If we want to reduce emissions and stop producing CO2, we need an energy-dense, carbon-free energy source, and ammonia is the solution. This region is ideal for ammonia production: for years, large volumes of the chemical have been shipped to and from Rostock. The Campfire consortium can make use of existing infrastructure.
The port of Rostock already has an ammonia storage facility. It's a relatively short distance across the Baltic Sea to Scandinavia. Green ammonia is also being pioneered there, so that’s a key focus for our collaboration.
We in the region believe we’ll soon be able to use ammonia as shipping fuel. But as is the case with so many green fuels, there’s a catch with ammonia, too: to date, there are no market-ready engines available. Scientists from the University of Rostock are hoping to change that.
They are involved in developing ammonia engines for use on ships. And here is the heart of the future yacht. Engineers and technicians are working on it now.
The scientists plan to install this engine in a yacht to research how ammonia-fueled engines behave at sea. None of this has been done before. We’ve installed a lot of safety checks, so if there’s a leak, we won't get any flashback fires.
We’ll dismantle the engine and reassemble it on the yacht. Safety measures are required because ammonia is toxic. Even at low concentrations, it can damage the skin, eyes and lungs.
While they work, the scientists must follow a strict set of guidelines. There has been little research into how ammonia behaves when burned in an engine. Nobody knows what to expect.
The scientists hope their work with this research engine will change that. They are ready to monitor everything from fuel consumption to engine temperature and composition of the exhaust. A ship running on ammonia would emit mainly nitrogen, which is already present in the air.
Another by-product: water vapor. Burning ammonia doesn’t produce carbon dioxide. .
. but it can create harmful nitrogen oxides, including nitrous oxide, a potent greenhouse gas that must not be released into the atmosphere. Sensors throughout the engine measure what levels of nitrous oxide or other nitrogen oxides are produced during combustion.
The researchers still need to develop catalysts to neutralize those unwanted compounds, but they are confident they will soon succeed. Only then can this type of engine be used in a ship. Beyond spearheading the development of these engines, Campfire is advancing the production of green ammonia.
The needed renewable energy is expected to come from wind turbines in the region. We cannot wait another 20 years to bring ammonia fuel to the market. We’ll need to get this job done within three to five years if we’re to achieve our goal.
There’s still a long way to go. But even industry leaders are interested in ammonia as a new shipping fuel. Jacob Sterling and his team are expected to launch Maersk's first zero-emission ships soon.
The company has brought its climate target forward: it now aims to be climate-neutral by 2040. Could ammonia be the solution? German physicist Berit Hinnemann, head of green fuel sourcing at Maersk, is looking into it.
Today, she will be inspecting a world first. Engineers at the research center of marine engine builder MAN in Copenhagen are developing a large ammonia engine that could be used to power container ships. The head of the research center, Bjarne Foldager, has come in to show Hinnemann the test engine.
Here you can see the bottom, and here where the piston connects to the crankshaft. At first, only one of the four cylinders will run on ammonia. Step by step, the team aims to test the whole engine.
We have, I think, more than 2000 sensors, including also high-speed cameras inside the combustion chamber. So, we can follow exactly what happens in each revolution of the engine. Then we can follow exactly how the flame is expanding and how efficient the process.
And we can make the adjustments. MAN estimates that developing the ammonia engine will last through 2024. Nobody knows exactly when the first engine will reach the market.
It must be really difficult to prioritize between all the things you need to test. Berit Hinnemann can see that ammonia isn’t a viable option yet. A lot of issues still need to be explored.
How do we design the ship so it’s safe? Bunkering how do we get the fuel on board? We need to answer all these questions.
Perhaps ammonia will be a solution in the future. But Maersk doesn't want to wait much longer. Global trade is growing and with it the fleets of cargo ships.
According to the International Maritime Organization, this could mean an increase of CO2 emissions of up to 50% by 2050. Without countermeasures, our increasing consumption will continue to burden the climate. It presents an ever-growing risk for humans and the environment.
But calls for change are growing louder. The impact of climate change is already being felt. And legal frameworks are being tightened.
In 2021, the EU published its "Fit for 55" program, with new climate protection legislation. We now have a package that can take us to our goal, which is now a legal obligation of reducing our emissions with at least 55% by 2030, which will set us on a path of climate neutrality by 2050. This proposal makes us front-runners.
Because this is the first legislative initiative of its kind for maritime transport. In 2024, regulators added maritime transport to the European emissions trading scheme. The Commission also ruled that, by 2050, ships must reduce their greenhouse gas emissions by 80%.
It was pretty clear that we needed to step up our efforts on decarbonization. And one of the results of that was the establishment of a decarbonization team that is dedicated for this agenda only. And, whereby now I think we are 50, 60 people working actually.
The team is working hard on finding a solution. We fairly quickly came to the solution that if we want to have impact in this decade, then methanol, green methanol, would be the right choice because the engine technology is ready. The Alfred Wegener Institute has also decided to back methanol technology.
The institute researches climate change and operates several research ships. In 2019, they decided to replace the science vessel Uthörn with a more climate-friendly ship. Biologist Michael Klages is overseeing the construction of the new Uthörn.
At the start, the team carefully considered various propulsion systems. Batteries would have been too heavy, liquid gas too expensive. Now we’re entering the engine room.
The engine is the heart of the ship. These are the two special engines. These were originally marine diesel engines but were converted to run on methanol for this ship.
An expert had informed Klages that methanol was an option. One of our shipbuilding consultants had a liter bottle of methanol in his suitcase. He put it on the table and said: Look, gentlemen.
This is how easy it is for me to bring you the shipping fuel of the future. Imagine the effort if I had wanted to bring liquefied natural gas in a pressurized container. The downside?
Methanol is only half as energy-dense as diesel. Ships require much bigger fuel tanks. This is the room with all the scientific equipment.
It was a challenge for the team at the shipyard to fit everything in. But they seem to have succeeded. It's amazing how much you can pack onto such a small ship.
It will be the world’s first ship of this size to run on green methanol. Construction of the new Uthörn began in 2020 at the Fassmer shipyard in northern Germany. It took almost two years to complete.
These are the vessel’s methanol engines. Methanol is mostly produced from natural gas. But officials at the institute wanted these engines to run on green methanol, produced from sustainably sourced hydrogen and CO2.
This is where things get complicated. A ship running on methanol emits mostly water vapor. But during combustion, the engines also release the CO2 used to produce the methanol.
For the methanol to be considered “climate-neutral”, this CO2 must not come from fossil sources. The fuel is only green if the carbon dioxide was extracted from the air or came from a natural source like a biogas plant. The fuel powering the Uthörn matches these criteria.
Someone recently said: small ship, big role model. And there's a lot of truth to that. Because with this vessel, we are following a path that no one has ever taken with a ship of this size.
That we are putting a nearly CO2-neutral research vessel into service is unique. We're happy and proud that we've managed to do it. The ship was finally ready to launch in the summer of 2022.
The new Uthörn sat on a launching ramp above the Weser River, ready to be put into the water for the first time. The date had to be postponed twice because essential components could not be supplied due to the war in Ukraine. Finally, everything was ready to go.
Success! She’s sea-worthy! The vessel was towed to a wharf where work could be completed.
The Uthörn was just about ready to depart but there was just one more problem. The next step is to find suppliers who can produce and sell us green methanol. That's a job for our shipping company.
Maersk faced the same problem - but on a much larger scale. A single container ship needs almost 300 times as much methanol as the Uthörn: around 50 thousand tons a year. But in 2021, only 200 thousand tons of green methanol were produced worldwide.
We found ourselves, say one and a half years back, in this chicken and egg dilemma where we on the one hand, were ready to order a ship that could run on green methanol, but we couldn't really see who would fill the tank. And on the other hand, we were talking to a lot of different potential green methanol suppliers that would want to supply us with methanol, but they couldn't get started on building up the production because there was no customer that was willing to commit. With Maersk’s decision in favor of methanol, this is now changing.
The shipping company is certain to need the fuel soon. Berit Hinnemann is responsible for procurement and knows it won’t be easy. The challenge is that these are completely new supply chains.
These are new projects, and plants for producing green methanol or green fuels on this scale have not yet been built. This can only be done in partnership. We at Maersk can't do this alone.
The whole industry must work together closely. What’s more, the transition to green fuels could increase costs for shipping companies many times over. It doesn't really make sense that the green fuels that do not pollute the planet are way more expensive than the fossil fuels that do.
And that has to change. The very concrete and practical step that both the EU and IMO have to take now is the implementation of a CO2 tax, a CO2 tax on shipping that would make it more expensive to use fossil-based fuel. Jacob Sterling and his team are counting on that happening soon.
They have ordered 19 methanol ships, which are now being built in South Korea. All of them can run on both methanol and diesel. They will be ready by 2025.
Maersk has already secured the green methanol needed for these ships. Several of their partners will increase production to 2 million tons over the next few years. But even that won't be enough in the future.
We also said, to send a clear signal to everyone in the industry, both engine manufacturers and fuel producers, that we would, from now on, only order ships that could run on green fuels. When a company leads the way, that can affect which fuel prevails. But it also sets an example and may have a certain promotional effect.
My dream for the future is to get the first green fuel projects off the ground. The first green methanol projects. We must start implementing the solutions.
Shipping is on the brink of a transformation. New technologies stand ready to power these giants of the seas. There could soon be a revolution on the water, one that would make cargo ships one of the cleanest means of transport in the world.
Green shipping is ready to launch. It’s waiting for a tailwind from business and government.
