LNG is no longer creating the buzz, ammonia is

Ammonia is emerging as the likely front-runner in the fourth propulsion revolution in the maritime industry driven by the sector’s urgent need to decarbonize. According to the predictions from the International Energy Agency (IEA), it will account for around 45% of global energy demand for shipping in 2050.

As was the case with LNG, ammonia is faced with a chicken and egg dilemma both from the supply side and the creation of the necessary bunkering infrastructure to the very technology that would be installed on board ships.

Nevertheless, engine manufacturer MAN Energy Solutions is confident that it would meet its target of developing a commercially viable, ammonia-powered marine engine by 2024. The engine would be intended for large, ocean-going containerships. Once the engine enters the market, the company plans to follow up on this breakthrough in 2025 by offering shipowners a retrofit package intended for existing maritime vessels.

“We will make an ammonia-engine, one way or the other, that’s for sure,” Kjeld Aabo, Director of New Technology for two-stroke promotion at MAN Energy Solutions, confirmed in an interview with Offshore Energy – Green Marine.

“It may be the fourth quarter of 2024, but that’s still our target and we do believe we can do that.”

The two-stroke engine being developed builds on the MAN B&W Dual-Fuel ME-LGIP Engine platform, which uses liquefied petroleum gas (LPG) as a low-emission fuel.

The research and development activities are taking place at the 2 stroke headquarters and  Research Center in Copenhagen, where multiple tests are being made to prove the technology works.

As a zero-carbon fuel, ammonia has an acceptable energy density and could be an economically viable option as it could be stored onboard vessels at a temperature of -33°C. There are two ways to produce carbon-free / neutral ammonia: via renewable sources such as hydrogen to get green ammonia or natural gas combined with CO2 capture to get blue ammonia.

The major issue when it comes to burning ammonia is its high toxicity, as its combustion may produce Nitrous oxide (N2O), which is a potent greenhouse gas. Hence the most important aspect to developing an ammonia-powered engine is making sure potential ammonia releases are prevented or minimized, and safe and quick handling of potential leakages is ensured.

“Testing of ammonia is different from other fuels being tested. It burns quite slowly, and you must have a lot of energy to ignite it. That means that it might have to run on a different amount of pilot oil, and we might even have to derate the engine. We don’t believe that we would have to opt for derating the engine, but quite frankly, it is the first time we operate a two-stroke engine on ammonia, so there might be some surprises. However, we are not in any way afraid that we cannot do it,” Aabo said.

Talking about overcoming the safety challenges in developing the engine, the deadline will be a tough one to achieve. Still, MAN Energy Solutions believes the target is realistic as there are no major bottlenecks to tackle.

“We have to ensure that the ammonia-burning engine is safe, and highly reliable. We also have to ensure that there is no N20 release, also known as laughing gas, which is a very harmful greenhouse gas. Furthermore, we need to make sure the ammonia slip is not too high in the exhaust gas. There will always be a little bit because that’s the way the process is. Finally, we need to make the engine compliant with Annex VI, Tier II, and III NOx Emission Standards and we know that actually, ammonia produces more NOx than diesel.”

Therefore, there will be a lot of things to consider when the company starts testing the technology in the beginning of 2022 on one of its big two-stroke test engines.

As explained, the engine is one part of the process, and MAN Energy Solutions is also working closely with classification societies in relation to the design of fuel components and the fuel gas supply systems.

“We are now going to Hazard 4 on the fuel gas supply system for the ammonia engine. This covers the ammonia tank all the way to the engine itself, including pumps, filters, as well as the gas valve trains that can ensure that the gas supply to the engine stops when the alarm sounds. We also need to ensure that when this happens, the system is in place to purge the piping with nitrogen, so pipes are cleaned from ammonia when you are operating on diesel or going into the harbour. We are working with DNV GL, ABS, BV and ClassNK on this,” Aabo noted.

“Last year, we hosted an event gathering 32 people from the industry for two full days. We looked at all the hazards that could arise from such a system. The outcome was for all three hazard scenarios that there was nothing safety-wise that was a bottleneck for making such systems. Our final design of the fuel gas supply system will be presented at the end of June this year, and we have also built that up in our test facility for testing.”

Our interviewee agrees with industry predictions that in the first decade of the shipping’s transition toward a greener future, we will see more engines operating on methane and LNG.

It is the most obvious solution, commercially available on the market. Yet, there are two sides of the coin when talking about LNG. Namely, even though it is being touted as the best available solution, there are numerous questions about LNG’s real carbon footprint well to wake.

“The IMO still faces difficulties in defining this issue and is yet to bring some clarity, so everyone is on the same page. The trend we see right now is that most owners are going for LNG, definitely. We have over 240 engines running on LNG ordered so far, in different sizes. Even though we have a methanol engine we don’t have a methanol engine of 60, 70 or 80 bore size yet in our programme. These are yet to be designed, and based on the overall request coming from the market. As technology providers, we have to listen to the market and adjust our development priorities accordingly when a business case matures and can cover the development overhead.  If you look at our engine portfolio, it is enormous and there is so much overlap because you have different engines for different applications in the marine business,”  Aabo said.

The trend so far has been to introduce alternative fuels on ships transporting those fuels as cargo, so methanol engines on methanol carriers, and the case has been similar for LPG and ethane carriers.

However, with the announcement from companies like A.P. Moller Mærsk on choosing methanol burning engines for one + one  2,200 TEU containership newbuilds this trend is starting to change, Aabo noted, adding that these different types of fuels are going to be utilized in other applications.

MAN Energy Solutions has been the maritime industry’s trailblazer when it comes to the production of dual-fuel engines, primarily focusing on LNG and LPG engines. Nevertheless, the company is keeping a close eye on the growing interest in using methanol as fuel.

“LPG has really taken the market by storm and we have now 79 engines sold. It is our last diesel cycle dual-fuel engine that we marketed in late 2019. In the last six months or so, all engines sold to LPG carriers were our engines, so you could say that we hold 100% market share for this segment thanks to this engine,” Aabo said.

Offshore Energy wanted to know whether there was still room for improvement of the dual-fuel engines running on the different dual fuels.

“As technology providers, we continue to improve our engines with different technologies, both the existing ones and those running on dual fuels,” Aabo said. “However, when it comes to significant improvement in efficiency looking at CO2 footprint of existing LNG dual-fuel engines, the answer is basically, no.”

“If you take our diesel principle methane burning gas engine, they have a very low methane slip and they are highly optimised. There is a possibility to start utilising the heat from the exhaust gas and cooling water, but ultimately, that heat would not make a big difference on the CO2 footprint.

“We can theoretically go from 55% to 63% efficiency, but that will only be at certain loads and it would result in high Capex, since you would need to invest in a lot of different equipment to collect and transfer the heat to whatever type of energy conversion system you would like to use it for.”

Dual-fuel engines running on LNG, LPG and methanol are by some part of the industry considered to be intermediate fuels and not long-term low carbon or carbon neutral solutions.  All can, though, be produced as e-fuels or for methanol or bio-methanol.

“Our experience shows that shipowners, yards, and many other companies these days are mostly looking at ammonia and methanol as long-term fuels,” he added.

“Of course, the funny thing is that there is no green ammonia right now, but there are many companies in and outside the marine industry that are looking at its development and utilization. So  at the moment we are mostly  speaking to customers about ammonia not about LNG.”

Be that as it may, ammonia will not be the silver bullet as the shipping industry presses ahead on its decarbonization path. The more likely scenario is that instead the industry is moving towards a multi-fuel future.

Aabo estimates there will be quite a number of different dual-fuel engines and fuels utilized in the future depending on the course of their respective developments.

“I don’t think that in 2040s there will only be ammonia that will be fuelling the marine industry,” he pointed out. Biofuels are expected to be part of the mix as well, even though they are likely to play a minor role.

“Some owners would like to operate on biofuels, which are quite costly right now, but that is likely to change in the future. Minor part of the shipping industry will be operating on biofuels and our engine is already ready for that.”

“We do believe that ‘dual-fuel’ is the future, because we see different interests for different fuels. As technology providers, we are not concentrating on one option, but on what we hear from market. This is what we prioritize in our development and I think that’s the way it has to go. Even so, you have to bear in mind that it is not easy to make a new dual-fuel engine. Despite the obvious technical challenges, which is always existing, it also takes a lot of power, human resources, testing and, at the end of the day, the endavour is quite costly.”

Commenting on the potential of nuclear power to play an important role in the shipping’s decarbonization path, Aabo indicated:

“The technology works, because we have seen it on large submarines and aircraft carriers in the U.S. Navy, so there is no issue from that perspective. I think it is the public and public acceptance, or lack thereof, which is an issue here.

“The possibility of collisions between nuclear-powered ships, and collision are quite common in the shipping industry, and the potential ramifications of such incidents is what the public is afraid of.

 “Basically, the question is whether these would be small nuclear bombs out at sea and whether we could see a lot of pollution from such incidents. I don’t think it’s the right way to go, because it would be far too difficult. What could be more realistic, since nuclear is one of the cleanest types of fuel available, is to use existing nuclear power stations to produce electricity to produce hydrogen and ammonia.”

In a recent announcement, Höegh Autoliners revealed that its new generation of car carriers, set for delivery in 2023, would be zero-carbon ready. The Aurora Class’ ships will feature a MAN E&S multi-fuel engines that can run on various biofuel and conventional fuels, including LNG. With minor modifications, they will be able to transition to use any type of zero-carbon fuels, including green ammonia.

Talking about the key considerations that need to be taken into account when designing multi-fuel and multi-function engines and preparing that for the future zero-carbon fuels, Aabo explained:

“Our foundation engine that will be used for the project is called ME-C fuel oil burning, and that’s what is sold today. An ME-C engine can technically be converted from fuel oil burning to one of the dual fuels currently available in dual-fuel engines. What is being referred to as multi-fuel does not refer to one engine but the number of fuels you can choose from now.

“There is no doubt that the intention in our development is to ensure that there are not too many variations of dual-fuel technologies. For example, for fuels like methanol, LPG and ammonia, which are all in a liquid state until they are injected into the engine system, all three of them use the same pump and piping system.

“It would be smart if we could have one concept that fits all, but we’re not there yet. This is especially the case for ammonia, which is harder to ignite etc. Therefore, we need to be completely sure what the design for ammonia-powered engines and fuel supply will look like before we can see if there’s anything that could be utilised both for methanol, LPG and ammonia-powered engines.”

Right now, the solution being proposed is a separate dual-fuelled engine for ammonia, and that also applies to other piping installation parts when considering retrofitting a vessel operating on LPG to ammonia.

“Basically, all the things that are dual-fuel LPG on this engine have to be exchanged to ammonia parts, since there are no similar components right now to fit both options. Nevertheless, that it is a hope for the future, but we are far from that and right now,” he pointed out.

“We are not far from making a common design, but how much can be used for both or all three liquid fuels we don’t know yet. What we are saying to customers in order not to promise anything is that today it is separate dual-fuel engine, but we have an ambition to make something common.”

The shipping industry has been notorious for moving too slow in the decarbonization process and, it has even been accused of not being too ambitious in setting its goals. From a technological standpoint, the engine manufacturing industry seems to be ready to produce engines that can run on zero-carbon fuels.

Speaking from a wider perspective, the uptake of those engines and new technologies faces the risk of remaining a challenge as numerous companies remain on the side-lines pending some type of incentive to take the plunge.

Commenting on what type of incentive that might be to drive the industry forward, regulatory, financial, governmental, or even a total ban on fossil fuels, Aabo said:

“Without a CO2 tax, the transition to zero-carbon fuels would be extremely difficult to implement. Being a very competitive business, of international character, shipping needs a common regulation and the transition cannot be done by single companies or regions, since CO2 is everywhere. The IMO would be the right body to enforce such a regulation. We see a lot of developments when it comes to Energy Efficiency Existing Ship Index (EEXI) and operational Carbon Intensity Indicator (CII), but this is not something that will actually change the situation for the environment .”

“Banning fossil fuels would be very difficult. Therefore, I think there needs to be a business case for operating on low or zero-carbon fuels supported by subsidies or, what is more realistic, regulated through a CO2 tax so that shipping companies can start using the green fuels.

“As soon as the IMO comes up with a CO2 tax, industry stakeholders can start considering what type of fuel will be the right option for them for the future. The good news is that most of the vessels ordered today are prepared for a dual fuel, in some way or the other,” Aabo concluded.