Shipping is heavily reliant on fossil fuels, and the huge majority of ships globally are powered today by hydrocarbon based fuel oils, albeit with some variation in grade and specification. Burning this fuel releases large quantities of carbon dioxide into the atmosphere, which significantly contributes to its insulative properties and to global warming and climate change.
Fuel oils have found favour in the marine industry, and almost all other industries, due to their high energy density, wide availability and the relative ease with which they may be stored, transported and handled, says an article published on Hill Dickinson website.
A challenge
Replacing ubiquitous and convenient fossil fuels is a challenge, which all industries face. However, some dimensions of the challenge specific to shipping include:
- Limited storage capacity on board ships coupled with, in some cases, long distances between land based refuelling stops
- The necessary proximity of fuel storage and human living quarters on board ships
- Uncertainty as to schedule and future ports of call and a preference to retain flexibility as to port calls
- limited storage capacity ashore at ports and terminals
Alternative fuels – candidates
Hydrogen
Pros: speed and ease of refuelling; green production by way of electrolysis powered by renewable energy is possible; suitable for use in fuel cells; falling cost of renewable energy may lower green production costs.
Cons: currently produced mostly from fossil fuel sources; green production currently expensive; low energy density, requiring 8 x more volume than fuel oils for equal power output, and consequent storage capacity issues; must be kept at -253C to be stored as a liquid; large capital investment needed for storage and refuelling infrastructure for shipping.
Ammonia
Pros: speed and ease of refuelling; green production, using green hydrogen and renewable power for the conversion process, is possible; conversion process relatively cheap and uncomplicated; already produced in substantial volumes for the chemical industry; handling issues in relation to marine transportation are already well understood.
Cons: highly toxic; the conversion process requires an additional input of energy compared to green hydrogen; requires energy input for refrigeration; less energy dense than fuel oils, requiring larger storage capacity and/or more frequent refuelling; large capital investment needed for storage and refuelling infrastructure for shipping.
Methanol
Pros: speed and ease of refuelling; low cost for conversion of existing engines; minor modifications to existing storage and bunkering facilities only; biodegradable, with a lower impact on the environment in the event of spillage; more energy dense than hydrogen and ammonia; relatively clean burning with low levels of SOx and NOx; liquid at ambient temperatures, no need to heat or cool.
Cons: lower energy density than fuel oil, requiring larger storage tanks and/or more frequent bunkering; low flash point represents a fire risk; toxic when inhaled, ingested or handled; increased corrosion risks; large capital investment needed for more widespread storage and refuelling infrastructure for shipping.
Can one fuel serve all needs?
As the ongoing machinations of the International Maritime Organisation (IMO) testify, accomplishing a single solution for shipping globally is challenging, and even if the industry were to agree to switch to a single alternative fuel, it is not practically possible to flick the switch overnight.
Changing fuel means huge investments in fuel production, infrastructure and supply chains, retrofitting of ship engines and storage and bunkering facilities, modification of fuel tanks and fuel delivery systems, retraining of crew and terminal staff, adjustments to contracts, and reappraisal and recertification of equipment and processes. It requires foresight, planning and collaboration extending beyond the shipping industry. It also requires fuel availability, at scale and at a viable price.
As recognition of this reality spreads, owners and operators are increasingly looking to find a solution that is right for their fleet and its activity, rather than waiting for a one-size-fits-all solution, and pockets of new practise are now emerging around the world in the form of trials, and one to several ship experiments.
Keeping the big picture in mind
Two important considerations for the industry to keep in mind throughout its transition to alternative fuels, are that:
- The objective of reducing greenhouse gas emissions from shipping exists in the context of an urgent need to reduce greenhouse gas emissions from all human activities; and
- The move to alternative fuels in industries other than shipping is an opportunity for shipping to downsize, given that a large percentage of the cargo it carries (some put it as high as 40%) is fossil fuel.
Conclusion
A variety of fuels may be deployed across the industry with not all sectors, or even ships within sectors, utilising the same fuel and possibly even with some ships utilising multiple fuels, and fuel supplements such as wind and solar power, aboard.
Production and upstream pollution, and the emissions of combustion products other than CO2, will be factors for consideration when selecting alternative fuels and at some point the industry may start to downsize, as a result of a global drop in demand for fossil fuels.
Summary
- Shipping is heavily reliant on fossil fuels, and the huge majority of ships globally are powered today by hydrocarbon based fuel oils.
- Replacing ubiquitous and convenient fossil fuels is a challenge, which all industries face.
- The industry has by no means agreed on a shortlist of alternative fuels.
- As the ongoing machinations of the International Maritime Organisation (IMO) testify, accomplishing a single solution for shipping globally is challenging.
Did you subscribe to our daily newsletter?
It’s Free! Click here to Subscribe!
Source: hilldickinson.com
