– By Neville Smith
Current high fuel prices and progressive regulation are acting as a two-prong driver for greater energy efficiency among shipowners. On the one hand, owners need designs that are increasingly fuel efficient as bunker costs continue to escalate, but they also understand the need to demonstrate energy efficiency for purposes of regulatory compliance and commercial differentiation.
Asian shipyards have mostly found that ships recently delivered or currently under construction could largely meet the IMO’s Energy Efficiency Design Index (EEDI), says ABS Vice President, Environmental Solutions Group, Ah Kuan Seah.
“Fundamentally the required EEDI is the average EEDI of existing ships built between 1999 to 2009, so newer ships, which, in general, have had the advantage of more recent and hence improved designs, tend to have better chances of meeting the 2013- 2015 EEDI Phase 0 requirements without re-inventing the wheel,” he says.
But he says Asian shipyards are investing in improving energy efficiency for their new designs with an eye to future requirements. The yards are taking this new requirement ‘very seriously’, and see energy efficiency as the competitive advantage to meet owners’ requirements for more commercially-attractive ships.
The work being undertaken by shipyards can be summarized in three main areas: machinery, propeller and hull form. The machinery aspect could typically include, for example, improving the waste heat recovery system for additional power generation. The propeller aspects may include devices that improve the wake as well as devices that recover energy downstream of the propeller. For the hull itself, further hull form optimisation could be achieved and hull resistance could be reduced with application of low friction coatings.
“A combination of these measures would potentially improve the ship’s energy efficiency enough to meet the EEDI Phase 1 requirements, which are 10% tougher than Phase 0,” adds Mr Seah. “More research and development is needed to make further improvements to meet the Phase 2 requirements and beyond. There are many emerging technologies on the horizon, but more work is needed on their development before they become widely available.”
Looking further ahead, shipyards and engine manufacturers are examining ways to optimise ship and engine designs across multiple operating speeds. The current practice is to design engines and ships for idealized conditions, which in practice the ship will hardly ever experience. Intuitively, says Mr Seah, ships should be designed and optimized for actual but variable operational conditions. Such a design approach could well be one of the means to achieve a more energy efficient ships of the future.
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