A scientifically researched schema promoting green ammonia as the best near-term way forward for shipping to achieve its carbon emission reduction targets is being presented to the IMO.

Ammonia made from renewable energy-generated electricity is the most practical zero-carbon marine fuel in the short to medium term if emissions are considered across the whole life cycle, argues the Environmental Defense Fund (EDF), an independent not-for-profit organisation.

There are downsides to ammonia, but unlike hydrogen, it has existing marine handling and risk procedures and does not require cryogenic storage. It is also relatively energy-dense as a liquid, making it possible to store sufficient volumes in tanks for long journeys. Existing dual-fuel engines can be relatively easily adapted to its use, or it can be co-fired with other fuels.

Ammonia, like hydrogen, does not contain carbon, so it produces zero CO2 emissions at the point of use. More importantly, green ammonia and renewably produced hydrogen offer nearly a 95% reduction in life cycle greenhouse gas emissions compared with high- or low-sulphur fuel oil or marine distillates, according to Lloyd’s Register.

But EDF international climate manager Marie Hubatova concedes: “The manufacture of ammonia and hydrogen is so energy-intensive that if you don’t do it from renewables, the emissions and the impact on the climate might be much worse than using conventional fuels.”

That is why the use of renewables-derived electricity is so important. But Hubatova also asserts that investment in solar and wind power can be an incentive for many less developed IMO member states and will in part be paid for from whatever bunker levy is adopted.

Professor Harilaos Psaraftis. Photo: DTU

The theory fits the case presented by last month’s report from University College London (UCL)’s University Maritime Advisory Services, which put a $1.4trn bill on realising the IMO target to halve carbon emissions between 2030 and 2050. Most of that would pay for land-based infrastructure to produce and supply new fuels.

It’s big money, but it won’t be wasted on green ammonia, whereas it might be on the fuel many are grasping at now — LNG —Hubatova insists.

“If you look at full life cycle emissions of LNG, it is as bad as other conventional fuels. When LNG escapes into the atmosphere unburnt, which occurs throughout the production chain, it releases methane, which has a 20-year warming potential over 80 times greater than carbon dioxide. It is still a climate-polluting fossil fuel that can worsen the current climate crisis,” she says.

“So from my perspective, LNG is a very poor investment decision. Why would you splash your cash on something that is not the solution?

“We are expecting the first commercial zero-emission vessels to be on the water by 2030, and that will require a substantial investment in infrastructure either for LNG or electrofuels. I think trying to undergo two major transitions in a decade is risky. It will divert the focus and split the money that could be used to build the right global infrastructure to deliver genuine zero-emission vessels.”

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Ammonia has to be stored at -34°C or under moderate pressure (1MPa or 10 bar) to be used as liquid fuel, when its volume is 4.1 times that of marine gas oil for a fixed level of energy content (compared with -253°C and 7.6 times for hydrogen).

About 1.4GWh of electricity is needed to provide enough ammonia fuel for one day’s sailing of a panamax boxship. The fertiliser industry exported 18.8m tonnes of ammonia from an average total annual production of 175m tonnes from 2015 to 2017. Current production levels would need to rise by 3.5 times to power the entire international shipping fleet.

Alternative zero-carbon fuels, renewable energies and a bunker levy can come together in a holy trinity; the aim being to clean up emissions across the whole life cycle of the fuels that shipping uses.

“We should look at these things together. The levy will be the tool to put alternative zero-carbon fuels in place,” Hubatova says. “The key is to ensure we reflect the full life cycle of a fuel when considering policy options.”

So, who is EDF to be telling the shipping industry how to put its house in order?

In the 1960s, a group of US scientists teamed up with a lawyer in response to research showing a decline in osprey chicks hatching due to poisoning from DDT. It led to a ban on the pesticide.

That court victory led to the founding of EDF, which has evolved into a global organisation with 2.5m members funding the development of policies on climate change and other environmental issues backed by scientific research. It is not linked to any governments or business groups.

Three years ago, the fund opened a European head office in London working mainly on climate and health issues. Hubatova started out working on carbon markets, then moved into the shipping sphere because the organisation felt it had something special to offer the debate.

“We find ways that work,” Hubatova says. “EDF is more connected to the science. We are somewhere between academia and NGOs and policy-makers — a mediator in the space, with everything we say backed by science and numbers.”

EDF has applied for consultative status with the IMO and will know by July if it has succeeded.

Before then, the IMO will this spring debate the market-based mechanisms it needs to help in the effort towards decarbonisation and to raise funds to develop greener fuels and technologies.

“The International Chamber of Shipping proposal for a bunker levy [of $2 per tonne for research] could be more ambitious, but it is a good start,” Hubatova comments. “I think it is more important to focus on the design [of the levy] than the figure, because you can change the numbers as you go. But it is most important now to get some kind of legislation in place.”

Any levy system must be robust and there has to be a ratchet mechanism to make sure the price can change over time, she adds, but it is equally vital to avoid wasting more time and to use the levy to put green ships on the water, not just pay for research.

But there are concerns about the costs of a levy. Some less developed countries are worried at even the low figure of $2 per tonne. And analysts agree a level many times higher would be needed to hit the $1.4trn final cost estimate.

It is more important to focus on the design [of the levy] than the figure, because you can change the numbers as you go. But it is most important now to get some kind of legislation in place

Marie Hubatova

In separate research into the market effects of a bunker levy versus speed reduction, Professor Harilaos Psaraftis of the Technical University of Denmark says some in the shipping industry are arguing that $10 per tonne should be used as a yardstick for a reasonable level.

But his calculations show a $500-per-tonne levy is required to halve CO2 emissions — a level so high as to be politically unacceptable. “Conversely, a low to modest levy (for instance, up to $10 per tonne) would not achieve much, in terms of either speed reduction or CO2 emissions reduction,” Psaraftis says.

Hubatova claims a tax on carbon emissions, rather than on fuel, would better reflect the environmental impact and be more motivating to shipowners or charterers wanting to prove their green credentials.

“The exciting part of the zero-carbon fuel transition is that investment into renewables is good for developing countries. Shipping can create so much demand for renewable energies that it would make it easier for them to become cheaper.”

A lesser reliance on fossil fuel imports would also be beneficial to many nations, and renewables development would improve their energy security as well as climate change prospects, she adds.

“Demand for green ammonia as a maritime fuel could provide a dependable long-term revenue stream — supported by long-term supply agreements — to unlock investment in renewable plants in developing nations,” argues an EDF report, Sailing on Solar, issued last year.

But there is also a long way to go with expanding renewable energies, and there are also nitrous oxide (NOx) emissions to consider.

“Combustion of ammonia also produces NOx, which is a greenhouse gas and depletes the ozone,” another EDF report, Electrofuels for Shipping, admits. “However, [nitrous oxide] emissions are not expected to be higher than those currently generated by combustion of conventional marine fuels.”

In Sailing with Solar, however, EDF claims: “Selective catalytic reduction [SCR] equipment can be used to reduce these emissions, similarly to new fossil fueled vessels in complying with Tier III requirements of Emission Control Areas [ECAs].”

SCR is a catalytic reaction using ammonia to reduce NOx to harmless nitrogen and water, and as it requires ammonia or urea to function, new vessels operating in ECAs already need systems to handle and store the chemicals.

Ammonia, like hydrogen or methanol, needs to be mixed with a small amount of carbonaceous fuel to maintain stable combustion in compression ignition engines. That results, according to EDF, in a small amount of additional CO2 emissions, which for ammonia would be more than 90% lower than diesel.

EDF adds that engine maker MAN plans to develop one of its models to run on ammonia, with efficiencies in the region of 50%, and has indicated that up to 3,000 existing engines could be retrofitted to use ammonia. The manufacturer expects it will take 2½ years to develop and test its engine for ammonia firing.

A longer-term aim is for shipping to use fuel cells that can operate directly on ammonia and eliminate emissions of nitrogen oxides and particulate matter. Solid oxide fuel cell technology is not yet commercially available for marine applications, but further development is expected to make it viable in the 2030s, according to EDF.Hubatova says her organisation is working on an emissions accounting system for shipping with UCL, in part using experience from the airline industry. They aim to present it to the IMO’s Marine Environment Protection Committee meeting in April.

The hope is that the IMO can enact global regulations that are in place by 2023 setting a carbon tax and rules accounting for whole-fuel emissions as an amendment to Marpol Annexe VI.

“I think there is a will within the shipping industry — hopefully there is a way as well,” Hubatova says.

A 210MW combined CSP and PV plant in Antofagasta, northern Chile. Electricity for a potential project to supply four plants in the Antofagasta port of Mejillones to produce ammonia for marine fuel would be generated by a PV array supported by two CSP plants. Photo: Cristobal Olivares/Bloomberg

The wind in their sails, the sun on their backs

The Environmental Defense Fund has commissioned two reports on the development of renewables-generated ammonia as a green marine fuel, focused on Chile and Morocco.

Chile, a strong voice at the IMO, is reliant on long-distance shipping connections to trading partners. The country is well suited to and relatively committed to wind, solar and hydro power.

The Electrofuels for Shipping study says solar plants covering 1,600 sq km would be needed to generate the electricity to meet Chile’s shipping demand for green ammonia every year, at a total investment cost of $70bn-$95bn. About 30% would pay for chemical plants and the rest for renewables development.

It calculates that producing green ammonia to refuel two 17,000-dwt vessels each day at the port of Mejillones in northern Chile would require four production plants each manufacturing 700 tonnes of the fuel daily. The electricity for the plants would be generated by a 306MW photovoltaic (PV) array supported by two 150MW concentrating solar power (CSP) plants with molten salt energy storage to allow operation through the night.

The entire merchant fleet serving Chile would need nearly 60m cubic metres of green ammonia per day.

An earlier EDF report, Sailing on Solar, predicts that up to $6trn would have to be spent building green ammonia and renewables plants round the world by 2050 to decarbonise the containership and non-coal dry bulk fleets, representing 40% of international shipping. Cost mechanisms to incentivise early fuel adopters would be required.

Sailing on Solar estimates a 250GW potential for offshore wind along Morocco’s coast — about 25 times its current total power plant capacity. That would provide enough electricity, 770 terawatt hours per year, to produce green ammonia for about one-third of the international fleet in 2012.

“The potential investment value (aggregate capital costs) of green ammonia plants and associated renewable electricity facilities in Morocco is in the region of $100bn,” the report adds.