Energy experts support carbon-free ammonia as a marine fuel

Energy experts support carbon-free ammonia as a marine fuel
According to Ricardo, these are the key benefits of using ammonia from renewable sources, such as wind and solar, as a marine fuel. Image courtesy of Ricardo

The transition to low and zero-carbon fuels must happen in 2020 if international shipping is to meet the IMO’s 2050 target of cutting greenhouse gas (GHG) emissions by at least 50 per cent compared with 2008 levels, Tim Scarbrough, associate director, Ricardo Energy and Environment confirmed this week.

Green ammonia, which can be used in engines and fuel cells, is produced using surplus or untapped renewable electricity sources, water and air. This results in near-zero lifecycle GHG emissions.  A webinar hosted by Ricardo with the Environmental Defense Fund discussed the role of ammonia in shipping’s transition to low carbon operations.

What are the benefits of green ammonia?

Ammonia is relatively energy-dense as a liquid, providing sufficient energy storage for ship voyages lasting several weeks, much longer than other renewable sources such as batteries.  Ammonia can be used without complicated onboard processing in internal combustion engines and in future fuel cells.

A key benefit of using ammonia to decarbonise is that it can already be done with existing and familiar technologies available today. It has existing global logistics infrastructure and as it is already used in ships today, often in selective catalytic reduction (SCR) systems, the transition to using it as a marine fuel should be simple, Mr Scarbrough explained on Thursday.

There are currently several actors involved in investing further into ammonia. One of these is MAN, which has indicated a development lead time of 2.5 years to adapt its engines to run on ammonia. The company announced plans to develop a two-stroke engine that will be based on its existing dual-fuel engine type to safely burn ammonia for marine fuel production.

According to Ricardo, the potential to develop green ammonia could provide long-term revenue and unlock investments in renewable plants in developing nations.

Morocco is one example where abundant renewable resources and ability to expand makes ammonia production viable. As well as being ranked 33rd in the world for total container output and with 10 active ports[1], Morocco also has an established inorganic ammonia sector where ammonia is stored near ports. According to Ricardo, Morocco has significant potential for development of solar and wind plants in the areas around existing ports that could be used to produce ammonia for marine fuel.

To bunker ammonia, facilities would need to be situated around the world. Morocco, as previously mentioned, is placed in a convenient location for delivering ammonia-based fuel to vessels on long voyages. Ricardo believes that bunkering facilities should be designed with the aim of optimising equipment to capitalise on economies of scale and operate effectively with electricity supplied by renewable sources.

How is ammonia stored and is it safe to handle?

Ammonia is stored in liquid at a temperature of around -33o C or moderate pressure, 1MPa (10 bar). It can also be mixed as a gas to be operated in dual-fuel mode. In addition, because ammonia is produced and shipped on a global scale, there are existing standards for the safe handling, storage and transport of ammonia in bulk on ships.

Cost and other considerations

Ammonia is currently not used as a marine fuel largely due to the high associated cost, said Mr Scarbrough. “It’s higher than existing fuels available for international shipping, including marine gas oil, LNG,” he explained. “Green ammonia cannot compete on price with current fuels so we need to incentivise. We need coordinated policy and regulatory incentives and to not penalise early adopters.”

One drawback of ammonia as a renewable fuel is the production of Nitrogen Oxides (NOx) from engine combustion. While Sulphur Oxides (SOx), Volatile Organic Compounds (VOCs), Particulate Matter (PM) are lowered with ammonia production, Mr Scarbrough acknowledged that the generation of NOx is something to consider.  However, as previously mentioned SCR systems that are often installed on ships to meet IMO NOx regulations can be used to cut NOx generated from the production of ammonia as a fuel.

As with all fuels, ammonia can be hazardous. Ricardo suggested that ammonia is less flammable than other fuels, posing a lower fire risk. Ammonia gas is toxic and corrosive, and existing safety principles and systems used throughout the ammonia industry would also need to be deployed on ships such as gas detection systems and appropriate chemically resistant protective clothing.

Current projects

A Dutch consortium including Yara is testing ammonia to establish its potential for use in the maritime industry. The two-year project is carrying out theoretical and laboratory work, which will result in a pilot-scale demonstration of the “the technical feasibility and cost effectiveness of an ammonia marine tanker fuelled by its own cargo.”

C-Job’s naval architect Niels de Vries, stated previously that, “One option that is just too promising to be overlooked is ammonia. Ammonia is easily sourced and has carbon-free emissions.” Last month, the company published new research on using ammonia as a marine fuel and found that as long as the right safety measures are in place, ammonia could be a viable zero GHG marine fuel.

Continued interest and buy-ins from leading actors within the sector as well as ongoing research from universities and institutions, and trialling technologies onboard smaller ships in Europe as is currently happening indicates that there is a lot of promise for the development of renewable ammonia as a marine fuel, confirmed Mr Scarbrough.

Hydrogen versus ammonia

To produce ammonia, nitrogen is combined with hydrogen via the Haber Process. There is some discussion in the industry as to whether hydrogen or ammonia is more viable as a long-term solution. Hydrogen requires cryogenic storage at -253 degrees Celsius, unlike ammonia, which means that ammonia requires less energy than hydrogen to liquefy, store and evaporate.  Ammonia also has a lower fire risk than hydrogen as it has a narrower flammable range.

Mr Scarbrough explained, “Ammonia offers more potential for longer range shipping, IF shipping wants to retain longer distances between refuelling. If the industry considers shorter distances between refuelling and bunkering then we might see more of a shift. Batteries could be suitable for short sea shipping but due to their size and weight, getting them on long distance ship maybe not so viable. Green ammonia versus green hydrogen – it is difficult to tell which one is better to invest in.”

Political will

Delivering renewable energy will partly be based on political will. Aoife O’Leary, senior legal manager, Environmental Defense Fund, Europe, said that the transition to low carbon fuels will be led by the IMO, however, if they fail to deliver the decarbonisation agenda, the EU will step in and push ahead. According to Ms O’Leary, the rate of decarbonisation will be based on countries’ understanding of the opportunities that new technologies and fuels can offer and the investment into developing countries around the world to build renewable plants. “Most countries focus on the negative impacts at the moment so we’re focussing on spreading positivity,” she explained.

To read more about ammonia as a marine fuel, click here to access Ricardo’s report ‘Sailing on Solar – Could green ammonia decarbonise international shipping?

[1] https://www.researchgate.net/publication/332845713_Sailing_on_Solar_-_Could_green_ammonia_decarbonise_international_shipping