Energy savings as high as 40 per cent and considerable reduction of greenhouse gas emissions can be achieved by incorporating new systems and approaches into the design of new ships, said a top official at Lloyd's register.
Fuel cells could eventually become the main energy unit in commercial ships when low-carbon technologies and renewable sources of energy are firmly in place, according to Dr Zabi Bazari, Ship Energy Services Manager for Lloyd's Register Marine Consultancy Services.
"Options such as optimised hull forms, latest foul release paints, the use of air cavity or air bubble systems, the use of sails for capturing wind and solar energies can save a considerable amount of energy," said Zabi.
He underlined how the energy lost in propulsors can be mitigated by the use of contra-rotating propellers, flow-wise integrated propeller-rudder systems and propeller boss cap fins as well as hull mounted fins upstream of propeller for streamlining flow at entry to propeller.
Zabi also identified the use of waste heat recovery systems, alternative fuels and electronic control common rail fuel injection system as the most effective and immediate means of reducing fuel consumption and emissions with existing engines.
But he considered fuel cells as the important and most likely long-term low and zero-carbon alternative.
"After a further three year period of research and development, we will see a period of adoption of fuel cell technology – primarily to gradually replace auxiliary power generation engines. But full replacement of existing engines/fuels combinations to fuel cell would not be likely for 20-30 years yet," he said.
Zabi also advocated improvements in measurement and monitoring, especially wide-scale ship-board energy metering to facilitate subsequent operational energy management.
The wider use of smart sensors and control systems, in particular for heating ventilation and air-conditioning systems (HVAC) and lighting systems, are now appropriate for new ships.
In a reference to current IMO initiatives on ship's energy efficiency design index, Zabi stated that regulatory changes will be the main driver for use of energy efficient and clean technologies.
New technologies will support future compliance and will deliver financial benefits if energy efficiency is taken into account at design stage by companies.