Energy efficiency: regulatory impact and the role of technology

21 Jul 2014
Current propeller designs offer energy saving potential, but for best results the various parts of the ship have to work together, and this means collecting and analysing data

Current propeller designs offer energy saving potential, but for best results the various parts of the ship have to work together, and this means collecting and analysing data

Shipping and offshore industries have gone through many changes in the last 10 years and it is likely that both will go through even more dramatic changes in the next decade and beyond, says Kirsi Tikka, president and COO, ABS Europe Division.

Oil exploration is moving to deeper waters and harsher environments and trade flows are evolving as new discoveries and unconventional sources join the energy mix. Shipping’s fundamental mission remains the same, but owners and operators must learn to adapt to ‘the new normal’.

This landscape combines a volatile earnings environment with the challenge of high fuel costs and an influx of new regulations with a hefty price tag attached. These are developments that will require the application of new technology, some of which has not yet been developed, in the quest for more efficient designs and operations.

The industry in general agrees that there is potential for improvement in fuel efficiency and in reduction of pollution emissions and with a couple of exceptions, the improvement is expected to come from new ways of thinking about ship design and operations.

The question is how much improvement is possible and cost efficient, with the technology available to the industry in the next decade?

While there have been technology improvements such as improved hull forms, better coatings, more efficient propellers and improvements to the efficiency of main and auxiliary engines, these have not had the same impact as conceptual changes and the introduction of bigger and bigger vessels.

The industry has also lacked a feedback system for operational performance. Classification has traditionally provided this for structural and machinery performance, by collecting data on failures and developing and amending rules to which the future ships are built, but no such system exists for operational performance and energy efficiency. Designers therefore have limited knowledge on the performance of their designs in actual operational and different weather conditions.

The current regulatory and economic drivers for energy efficiency have led the engine manufacturers, propeller designers, ship designers, and increasingly the shipyards, to work on new, energy efficient designs and equipment that can be used on both new and existing ships.

Many old energy saving ideas have been resurrected and, with the help of more efficient computational tools, some of them have been commercialised successfully. Some novel ideas have been introduced but are still only at a concept stage. At the same time, the industry is looking at ways to improve, measure, and benchmark operational efficiency.

Improvements in energy efficiency start with the hull form, which is constrained by the functional requirements of the vessel. The changes for ships with a high block coefficient, such as bulk carriers and tankers, are focused on the bow and the stern, whereas for lower block coefficient ships such as containerships, the hull lines overall are being optimised.

Available numerical tools have also improved and a large number of different hull forms can be analysed before verification of the results by model tests. The same applies to the various energy saving devices such as ducts, propeller boss fin caps, and pre-swirl devices. CFD (computational fluid dynamics) makes it possible to investigate the losses in the flow fore and aft of the propeller and to customise energy saving devices to a specific hull form and rudder propeller configuration, as well as to study the propeller/rudder interaction

Modern ships have sophisticated control and monitoring systems and if the data from the ships can be accurately collected and analysed, it may allow the operators to make better-informed decisions that can also improve operational efficiency. Performance monitoring systems with varying levels of sophistication are already available - some use hydrodynamic models, others are based on statistical models.

This is an opportunity to demonstrate to shipping that the collection and analysis of ‘big data’ can have a positive benefit. Many of the solutions being implemented today have been around for decades but were not commercially feasible in the past. It is the market economics and the regulations that have changed the landscape.

The scale of energy efficiency and regulatory challenge facing the shipping industry is considerable. Even with the resurrection and refinement of some old concepts and the introduction of new tools and methodologies, we will very soon hit a ‘wall’ in terms of the degree of savings that can be practically achieved.

These market needs and regulatory drivers have together created exciting opportunities for engineers and scientists. However, to make significant improvements in energy efficiency, a step-change is needed. The challenge to the research community is in the development of novel concepts and solutions that can significantly reduce the environmental footprint from shipping and make what is already an efficient mode of transportation, even more effective.

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