Hydrogen is a great fuel source compared to current carbon-intensive fuel sources, such as heavy-oil fuel that is mainly used on ships. When combusted with oxygen or consumed in a fuel cell, hydrogen does not directly emit carbon dioxide. Hydrogen is also versatile as a fuel, because it can be used as a feedstock for other fuels such as ammonia and methanol. ^[1]Fan, Zhiyuan, Emeka Ochu, Sarah Braverman, Yushan Lou, Griffin Smith, Amar Bhardwaj, Jack Brouwer, Julio Freeman, and Colin McCormick. Rep. Green Hydrogen in a Circular Carbon Economy: Opportunities … Continue reading  Hydrogen is particularly promising in the long-range shipping industry, since it can be stored for long periods of time and in large quantities. Hydrogen fuel cell technology for ship engines already exists, and can even be retrofitted to existing ships. ^[2]Reinsch, William Alan, and Will O’Neill. “Hydrogen: The Key to Decarbonizing the Global Shipping Industry?” Hydrogen: The Key to Decarbonizing the Global Shipping Industry? | Center for … Continue reading

While hydrogen itself is abundant in the form of various chemical compounds, pure hydrogen has to be produced from other compounds, since it is rare. Unfortunately, most of the processes to produce hydrogen also produce CO₂. 95% of hydrogen produced today is made from fossil fuels. ^[3]Gencer, Emre. “Hydrogen.” MIT Climate Portal. Accessed November 16, 2021. https://climate.mit.edu/explainers/hydrogen. Hydrogen is typically classified by how it is produced: “grey” hydrogen is produced from natural gas, “brown” or “black” hydrogen is produced from coal, and “blue” hydrogen is produced through one of these methods but with the CO₂ emissions captured and stored, having net zero emissions.  “Green” hydrogen is produced through electrolysis- the splitting of water into hydrogen and oxygen molecules- through various processes involving zero-carbon electricity. ^[4]Fan, Zhiyuan, Emeka Ochu, Sarah Braverman, Yushan Lou, Griffin Smith, Amar Bhardwaj, Jack Brouwer, Julio Freeman, and Colin McCormick. Rep. Green Hydrogen in a Circular Carbon Economy: Opportunities … Continue reading

When it comes to switching to hydrogen as a low-carbon fuel source, green hydrogen is ideal. Unfortunately, while the processes to produce green hydrogen exist, they are not currently widespread, mostly due to their comparatively high cost. ^[6]Fan, Zhiyuan, Emeka Ochu, Sarah Braverman, Yushan Lou, Griffin Smith, Amar Bhardwaj, Jack Brouwer, Julio Freeman, and Colin McCormick. Rep. Green Hydrogen in a Circular Carbon Economy: Opportunities … Continue reading One of the barriers to producing green hydrogen is the current electric grid. The net emissions of green hydrogen are dependent on the electricity used during its production process. If the green hydrogen is produced using electricity from a net-zero emissions grid, then it has no net carbon emissions. Thus, the switch to green hydrogen is largely dependent on the switch to zero-carbon energy sources on a larger scale. ^[7]Fan, Zhiyuan, Emeka Ochu, Sarah Braverman, Yushan Lou, Griffin Smith, Amar Bhardwaj, Jack Brouwer, Julio Freeman, and Colin McCormick. Rep. Green Hydrogen in a Circular Carbon Economy: Opportunities … Continue reading

There are other challenges to hydrogen as a fuel source in addition to its production. The largest of these challenges has to do with the storage of hydrogen. Since it is a small molecule, it must be compressed, liquified at extremely low temperatures, or stored using a porous material. It is also more prone to leakage than other gaseous fuels, and is not compatible with much of the current infrastructure due to how it reacts with pipeline steels. ^[8]Fan, Zhiyuan, Emeka Ochu, Sarah Braverman, Yushan Lou, Griffin Smith, Amar Bhardwaj, Jack Brouwer, Julio Freeman, and Colin McCormick. Rep. Green Hydrogen in a Circular Carbon Economy: Opportunities … Continue reading

In conclusion, while hydrogen is a very promising fuel alternative, the current challenges to green hydrogen production result in it being a more long-term solution. The transition to green hydrogen as a cost-competitive and widely available fuel source will require significant public investment in other green energy sources, government subsidies of hydrogen, and hydrogen storage and transportation infrastructure. That transition will also rely on technological advancements in the green energy sector and green hydrogen production. Unfortunately, minimizing the emissions from maritime trade cannot wait for the challenges of hydrogen fuel to be overcome. 

In many ways, ammonia is an extremely promising potential fuel source. Ammonia can be used to produce energy either by burning it in a combustion engine or with a fuel cell,^[9]Gallucci, Maria. 2021. “Why the Shipping Industry Is Betting Big on Ammonia – IEEE Spectrum.” February 23, 2021. … Continue reading or a device that uses chemical reactions to convert the energy in fuels to electricity.^[10] Schumm, Brooke. n.d. “Fuel Cell.” In Encyclopedia Britannica. https://www.britannica.com/technology/fuel-cell. However, there are several obstacles to using it as a fuel source for ships that make adoption in the short-term unfeasible.

Currently, ammonia production is fairly carbon-intensive. The process used to produce ammonia, known as the Haber-Bosch process, is responsible for 1.8% of the world’s annual CO₂ emissions.^[11]Gallucci, Maria. 2021. “Why the Shipping Industry Is Betting Big on Ammonia – IEEE Spectrum.” February 23, 2021. … Continue reading However, it is possible to produce green ammonia that has close to no CO₂ emissions. Ammonia is made up of hydrogen and nitrogen. Green ammonia is made from green hydrogen, which is hydrogen produced from water electrolysis powered by renewable energy. This hydrogen is then bound to nitrogen to produce ammonia in the Haber-Bosch process, also powered by renewable energy. ^[12]Murray, Adrienne. 2020. “The Foul-Smelling Fuel That Could Power Big Ships.” BBC News, November 6, 2020, sec. Business. https://www.bbc.com/news/business-54511743. Because all steps of the process are powered by renewable energy, there are minimal carbon emissions in the production of green ammonia. 

Despite its potential promise as a zero-carbon fuel, there are several dangers associated with the adoption of ammonia. Ammonia is toxic, and so it would require additional safety measures such as the installation of emergency ventilation systems to keep ship workers safe if using it. In addition, ammonia can corrode some metals and plastics. 

Ammonia also has several challenges when used in a combustion engine. It is difficult to burn and may have to be combined with other substances such as diesel fuel or liquid hydrogen to make it ignite more easily. While ammonia has no CO₂ emissions, it does produce nitrous oxide emissions when burned. Nitrous oxides cause acid rain and are a more potent greenhouse gas than CO₂. Using ammonia in a fuel cell does eliminate these harmful emissions. However, current fuel cells cannot produce enough power for a ship. ^[13]Gallucci, Maria. 2021. “Why the Shipping Industry Is Betting Big on Ammonia – IEEE Spectrum.” February 23, 2021. … Continue reading

While there are multiple projects in progress to develop ammonia ships, they are all years from completion. For example, the Norwegian company Eidsvik is planning to use ammonia fuel cells to power an electric motor on one of its vessels by the end of 2023,^[14]Murray, Adrienne. 2020. “The Foul-Smelling Fuel That Could Power Big Ships.” BBC News, November 6, 2020, sec. Business. https://www.bbc.com/news/business-54511743. and Samsung Heavy Industries is working with MAN Energy solutions to create an oil tanker that runs on ammonia by 2024.^[15]Gallucci, Maria. 2021. “Why the Shipping Industry Is Betting Big on Ammonia – IEEE Spectrum.” February 23, 2021. … Continue reading

The main reason that Terrascope 2025 chose not to focus on ammonia is that it cannot be implemented at a large scale in the short term. The technology to make ammonia vessels is still not well developed. While it may be a promising fuel for the long-term future in shipping, Terrascope 2025 chose to focus on solutions that could be implemented in the relatively near future.

Powering ships using nuclear power has many advantages. It’s carbon neutral, allows ships to travel about 50% faster than oil-fueled ships, ^[16]Contributor, Glenfiddich. “Glenfiddich Brandvoice: Meet High Achievers Reimagining Wealth.” Forbes, Forbes Magazine, 28 Oct. 2021, … Continue reading a chunk of uranium the size of a grapefruit will power the ship for upto 60 years with the proper set up. ^[17]“Economically Feasible Mobile Nuclear Power Plant for Merchant Ships and Remote Clients.” Taylor & Francis, https://www.tandfonline.com/doi/full/10.1080/00295450.2018.1546067 It’s also a huge cost saver in the long run since the running cost of fuel is no longer an economic factor  and the ships won’t need to stop for refueling or waste a lot of space on fuel storage. However, it’s not a solution that can be immediately implemented since ships can’t be simply modified to use nuclear-power; they need to be specially built for nuclear-power.^[18]“Nuclear Merchant Ships: Five Fast Facts.” ANS, https://www.ans.org/news/article-2010/nuclear-merchant-ships-five-fast-facts/ A ship needs to have the proper safety parts and a completely different engine which is too large to install in an existing ship. Since ships are a large economical investment, this may be a problem for companies expecting a 20-30 lifespan.^[19]Maritime Vessel Obsolescence, Life Cycle Cost … – Iopscience. https://iopscience.iop.org/article/10.1088/1757-899X/95/1/012067 Another important point to mention is that the initial costs associated with building and fueling a nuclear-powered ship are 2-2.5 times ^[20]Namikawa, Shunichiro, et al. “Nuclear Powered Ships. Findings from a Feasibility Study.” Nuclear Powered Ships. Findings from a Feasibility Study (Conference) | ETDEWEB, 1 July 2011, … Continue reading greater than those in an oil-powered ship. This is yet another discouraging factor for companies in the short-term. Finally, it should also be noted that the public image of nuclear energy is negative at the moment, due to the past accidents involving leakages and improper disposal. Companies might face a lot of backlash from people who are against the use of nuclear-power, and employees could possibly leave due to fear for their health.

While electrification of shipping is promising for short distance routes, implementation in longer routes is largely agreed to be infeasible. ^[21]Appl-Scorza, Sophia, Jana Lippelt, and Christina Littlejohn. “Challenges of Electrification of Heavy and Long-Haul Traffic.” CESifo, 2018. … Continue reading The key problem with introducing electricity as a fuel for ships is the challenge of scaling up batteries to support the amount of energy necessary to travel over long distances. The first electric container ship, the Yara Birkeland, began operating in 2019. However, the most advanced diesel ships can currently carry 150 times as much cargo as the Yara Birkeland, 400 times further and three to four times faster.^[22]Smil, Vaclav. “Electric Container Ships Are Stuck on the Horizon.” IEEE Spectrum, February 29, 2019. https://spectrum.ieee.org/2021-top-10-tech-cars. Additionally, existing diesel ships utilize diesel fuel with an energy density of about 11,700 watt-hours per kilogram (Wh/kg), while today’s lithium-ion batteries run at 300 Wh/kg.^[23]Smil, Vaclav. “Electric Container Ships Are Stuck on the Horizon.” IEEE Spectrum, February 29, 2019. https://spectrum.ieee.org/2021-top-10-tech-cars. For a ship to run on an electric engine that produces as much energy as a diesel engine, the batteries would need to have an energy density more than 10 times as high as existing lithium-ion batteries to account for both battery weight and efficiency .^[24]Smil, Vaclav. “Electric Container Ships Are Stuck on the Horizon.” IEEE Spectrum, February 29, 2019. https://spectrum.ieee.org/2021-top-10-tech-cars. Additionally, the energy density of the most advanced commercial batteries hasn’t yet quadrupled in the past 70 years .^[25]Smil, Vaclav. “Electric Container Ships Are Stuck on the Horizon.” IEEE Spectrum, February 29, 2019. https://spectrum.ieee.org/2021-top-10-tech-cars. Considering the immediate nature of the climate crisis and the short term scope of this proposed solution, electrification of shipping is not further considered.

Liquefied natural gas (LNG) is sometimes considered a popular alternative fuel because it is seen as a transition phase from coal to green fuels. ^[26]The Carbon-Neutral LNG Market: Creating a Framework for Real Emissions Reductions. Columbia Sipa Center on Global Energy Policy. (2021, July 8). Retrieved November 17, 2021, from … Continue reading It is increasing in popularity, and over 150 ships are already using LNG. ^[27]Hickin, P. (2020, June 4). Analysis: LNG fails to Answer Shipping’s big energy transition question. S&P Global Platts. Retrieved November 17, 2021, from … Continue reading However, when accounting for its costs and unintended consequences, LNG is relatively ineffective in addressing the goal of reducing greenhouse gas emissions. 

Methane, the main component of liquefied natural gas, is a much stronger greenhouse gas than carbon dioxide, contradicting its goal of reducing emissions. ^[28]Questions grow on LNG’s carbon footprint, despite demand increase. IHS Markit. (2021, June 14). Retrieved November 17, 2021, from … Continue reading Estimates from IHS Markit, an information analytics company, state that methane is 84 times more potent than CO₂. ^[29]Questions grow on LNG’s carbon footprint, despite demand increase. IHS Markit. (2021, June 14). Retrieved November 17, 2021, from … Continue reading This means that within 20 years, each kilogram of methane captures around 84 times more heat than that same amount of carbon dioxide. ^[30]UNECE. (n.d.). The Challenge. Methane Management. Retrieved November 17, 2021, from https://unece.org/challenge.  Although LNG emits around 50% less carbon dioxide than burning coal does, many calculations of the total greenhouse gas emissions do not consider methane slippages. ^[31]The Carbon-Neutral LNG Market: Creating a Framework for Real Emissions Reductions. Columbia Sipa Center on Global Energy Policy. (2021, July 8). Retrieved November 17, 2021, from … Continue reading Most of the engines for LNG are around 98% efficient, meaning that around 2% of the methane is not burned and is released into the air as a gas, which is called a methane slip. ^[32]Barry, M. (2019, November 14). Reducing methane emissions from energy use. Methane Guiding Principles. Retrieved November 17, 2021, from … Continue reading
In addition, although the cost per volume of LNG is cheaper than methanol, there are other costs associated with modifying the ship engines for LNG that are much greater than methanol’s modifications. It is estimated that modifying the ship engines to adapt to LNG costs two to three times the cost that it takes to make those modifications for methanol. ^[33]Methanol as a marine fuel report – Methanol Institute. (n.d.). Retrieved November 17, 2021, from … Continue reading Investing in LNG could potentially be equally or even more harmful than the status quo in the long run; therefore, methanol is the recommended option.

Biofuels carry energy derived from organic materials usually referred to as biomass. In the current transportation sector, liquid biofuels made from vegetable oil (biodiesel) or other types of crops are used. These are known as first generation biofuels, or fuels such as bioethanol and biodiesel that are produced from agricultural products such as sugar cane and rapeseed. Second generation biofuels are made from non-food plant matter such as agricultural or municipal wastes, or crop residues. These are currently being developed and could be used in the long run, approximately 10 years. ^[34] Glossary: Biofuels. Accessed November 20, 2021. https://www.greenfacts.org/glossary/abc/bio-fuels.htm.

SVO (Straight Vegetable Oils), biodiesel, and bio-LNG (Liquified Natural Gas) are usually considered the first generation of biofuels. While SVO is produced from soybeans and rapeseed, biodiesel is a fatty acid alkyl esters mixture. ^[35]Kesieme, Uchenna, et al. “Biofuel as an Alternative Shipping Fuel: Technological, Environmental and Economic Assessment.” Sustainable Energy & Fuels, vol. 3, no. 4, The Royal Society of … Continue reading However, there are some problems connected to these fuels. They are made of biomass that has to be produced somewhere, oftentimes the same space  food could be produced. Every area where biofuels are produced takes place away from the food production. This means that the production of biofuels is potentially limited, making the worldwide implantation of them hard. The cost of feedstock for the biomass accounts for 75% of the cost of diesel ^[36]Kesieme, Uchenna, et al. “Biofuel as an Alternative Shipping Fuel: Technological, Environmental and Economic Assessment.” Sustainable Energy & Fuels, vol. 3, no. 4, The Royal Society of … Continue reading Because of this, a cheaper method of production of biofuels is needed in order to compete with fossil fuels. The cost of biodiesel is higher than diesel fuel. The price of the biodiesel is around $0.40 to $0.53 per litre before taxes, while diesel only costs $0.20–0.24 per litre. ^[37]Kesieme, Uchenna, et al. “Biofuel as an Alternative Shipping Fuel: Technological, Environmental and Economic Assessment.” Sustainable Energy & Fuels, vol. 3, no. 4, The Royal Society of … Continue reading Because of the financial and productional problems mentioned above, first generation biofuels are not easily implemented or economically feasible in the short run.Bio-methane or bio-LNG could be options in the long run (~10 years). Transporting biomethane and bio-LNG requires cryogenic tanks ^[38]Kesieme, Uchenna, et al. “Biofuel as an Alternative Shipping Fuel: Technological, Environmental and Economic Assessment.” Sustainable Energy & Fuels, vol. 3, no. 4, The Royal Society of … Continue reading to be installed on the ships, as well as storage facilities along the way.

Retrofitting ships is not being pursued as a potential solution because we are narrowing our scope and focusing on short term solutions. However, retrofitting is a strong solution for long term plans. 

Retrofitting a ship is building upon current infrastructure to improve energy efficiency, meet equipment standards, and save costs. Rather than building an entire new fleet of ships, ship owners can make adjustments to the current ship structure to keep ships in line with current sustainability standards and reduce CO₂ emissions. For example, ship owners can implement technology like Blueflow, an online cloud system, which integrates easily with already existing onboard technology and enables crews to evaluate navigation and monitor energy consumption on the ship. According to a study by The Retrofit Project, using Blueflow can cut fuel consumption and reduce CO₂ emissions by up to 1,989 tons/year.^[39]“The Retrofit Project.” Green Ship of the Future, 2020.  

Despite this potential solution, most retrofit projects are not feasible as a part of our solution. Examples of retrofitting solutions and ship design changes include rotor sail technology and LED energy efficiency lighting. These projects are not being pursued as potential solutions because they require more significant changes to ship structure, and the payback period for these projects is often too long to incentivise ship owners to make the investment. For example, LED energy efficiency lighting can reduce CO₂ emissions by up to 101 tons/year, but the return on investment would not be realized for 8.2 years.^[40]“The Retrofit Project.” Green Ship of the Future, 2020.  Thus, this lighting system is considered a long term solution and not logical within the scope of our project, as there is no immediate economic benefit for ship owners. 

Originally, we thought that including retrofitting in our proposal would effectively minimize ship CO₂ emissions and make shipping more sustainable. However, the scope of our research was too large. As a team, we did not have the capacity to thoroughly investigate retrofitting as a potential solution, so we came to the conclusion that cutting all forms of retrofitting and changes to ship design was the best way to help us narrow our scope and focus our research. Instead, we chose to pursue forms of alternative energy because this solution will have more immediate economic and environmental benefits.