26 Jul 13 - 15:13
Royal Academy of Engineering study examines future ship powering options
A new study by the Royal Academy of Engineering examines all future options for ship propulsion.
The Royal Academy of Engineering working party of more than 20 eminent engineering experts, led by John Carlton FREng, Professor of Marine Engineering at City University London, made a comprehensive survey of current and potential future marine propulsion systems, measuring them against the twin but related objectives of energy efficiency and environmental sustainability. Options investigated included greater use of LNG (liquefied natural gas) in current power units, battery and alternative fuel technologies, and nuclear-powered ships.
The working party identified a range of short-, medium- and long-term ship propulsion options:
- In the short term and with current propulsion units, LNG is a known technology with standards already in place, and is cheaper and cleaner than diesel, but requires a global infrastructure. Gas turbines are a niche and the fuel is expensive, while renewables such as wind and solar may have application as auxiliary sources of power.
- In the medium and long term, biofuels and synthetic fuels are potential direct replacements for current fuels, but more needs to be done on the practicalities of storage, handling and environmental impact. Fuel cells of varying kinds offer promise, but require infrastructure investment and technological development to meet shipboard power requirements. Shipborne nuclear power has been used in naval ships, but for merchant shipping there would need to be changes in design, building and operational methods. Current battery technology may be restricted as a prime mover to smaller ships, but offers potential as an auxiliary power source.
Further ahead, the report says that hydrogen could be an option for marine propulsion, but there are significant infrastructure issues as well as technology issues to be overcome. To develop future ship propulsion systems within reasonable timescales, research and funding are needed in a number of areas
According to the study, the following options are considered appropriate:
- For existing ships, reciprocating engines with exhaust gas attenuation technologies are the principal option together with fuels that produce fewer CO2 emissions. LNG is one such fuel and, together with some other alternatives, would require an adequate bunkering infrastructure to be developed, particularly for deep sea voyages. Some attention could also be usefully paid to reducing the demand for shipboard energy.
- For new buildings planned in the near-term, the scenario is broadly similar but with the option to include hybrid propulsion systems depending on ship size and intended use.
- In the case of ships to be built in the medium- to long-term, further propulsion options include alternative fuel options, fuel cells, batteries and nuclear. The former methods await technological development but nuclear, while well understood technically, would require a major change to ship owning and operation infrastructure and practices
Find more information by reading the study conducted by the Royal Academy of Engineering entitled as Future Ship Powering Options: Exploring alternative methods of ship propulsion. The study is available at www.raeng.org.uk/futureshipping
