Energy management is pivotal to the cruise industry for economic and environmental reasons. From powering ships by sails and natural gas to reshaping hulls, slowing cruising speeds and simply switching off lights, saving energy is big business.

Sulphur Emission Control Areas (SECA), with an allowable sulphur content of 1%, came into force in July 2010. This limit is set to be further reduced to 0.1% by 2015, a tough deadline to meet.

A further drive for energy efficiency is the global regulatory regime being drafted by the IMO to limit and reduce greenhouse gas emissions from shipping operations. Mandatory requirements are being drawn up for an Energy Efficiency Design Index for new vessels and a Ship Energy Efficiency Management Plan for existing ships. Dr Zabi Bazari, ship energy services manager for Lloyd’s Register, says that all these factors are putting a strain on the industry.

“The cruise industry faces significant reductions in SOx, NOx emissions and possibly CO2 in the future.”

“In terms of the environment, the industry faces significant reductions in SOx, NOx emissions and possibly CO2 in the future,” he says. “Compliance to these regulations will be tough and costly. The incentives for the industry are normally a combination of financial, regulatory compliance and image or brand.

“So far, the financial dimensions have played a larger role in moving the industry to more energy-efficient shipping. However, with the IMO’s energy efficiency regulations at its latest stage of approval, plus prospects for future marine market-based instruments such as CO2 trading or fuel levy, the regulatory pressures will be building up.”

Action required

So, where will the efficiencies come from? There are three main areas of energy use: propulsion accounts for about 60% of fuel consumption, hotel loads including HVAC for around 30% and auxiliary equipment for the remaining 10%. The potential exists for energy savings of up to 40%, according to Bazari, but these have to be weighed against the environmental impact of the technologies themselves and the cost.

“I believe today’s technological potential for energy saving is not as high as 40% if the cost factor is taken into account,” he says. “However, with changes to financial parameters such as fuel prices, charging for CO2 and a reduction in the unit cost of new technologies, most of the technologies will become cost effective in the future. So target reduction levels of 40% over the medium to long term are realistic and achievable. Operationally, we have evidence that a big scope for energy saving exists if ship itinerary, ship trim, condition of hull, use of new paints and more operational and technical controls are implemented on existing vessels.”

Energy-saving refinements

One vessel where energy saving is a strategic objective is The World, which is operated by ResidenSea. Built in Rissa, Norway, in 2002, it has since incorporated many environmental and energy-saving technologies. A host of refinements underway in 2010 include engine configurations to use main engines as shaft engines to consume less fuel, replacing halogen lamps with infrared coated lower wattage lamps, replacing lighting with LED fixtures for savings of 90% and introducing an ‘energy save mode’ for heating, ventilation and air conditioning.

John Schneider is responsible for the overall management of The World within the Marine Operations Department of ResidenSea. He says that as time and technology move forward there are always new ways to make the vessel more efficient, resulting in less fuel consumption and emissions (NOx, SOx, CO2 and PM), which in turn reduce the vessel’s carbon footprint and make it one of the greenest vessels sailing the seas.

“The World is the first ship of its size burning only marine gas oil rather than heavy bunker fuel.”

“We are always exploring these new technologies along with the vessel operations in order to accomplish these energy savings initiatives,” he says. “Some of these can be implemented while the vessel is underway and others during the 2013 dry docking.”

He explains that the dry dock will offer an opportunity to reduce the resistance of the hull by grinding the hull welded seams, using silicon-based foul release coatings, and looking at propeller blade design and gratings on bow thruster tunnels to reduce resistance.

Fuel cells and sail power

Across the industry there are several options for energy optimisation. In the short term, operation and technical management and speed reduction are the easy gains, with hull and propeller optimisation also a focus. Longer term, research is focusing on alternative fuels, renewable energy, biofuels, heat recovery and engine efficiency. Fuel cells and even the re-introduction of sails to ships are ideas being considered.

“Fuel cells produce very little exhaust pollutant and as such are considered a very clean technology but they are still in their infancy,” Bazari explains. “Fuel cells are being prototype-tested and will take several years before they move to full standard production units. They will be deployed initially to supply part of auxiliary power, then after full scale production they will gradually replace the ship’s auxiliary power. Over very long term, they will supply power for propulsion.”

A return to sail power is less certain. “Although the use of sails could give another interesting dimension to the cruise experience, my view is that sails will have limitations due to shorter port-to-port voyage times, passenger safety, lack of wind or the difficulty of aligning to the wind along a cruise route,” he adds.

More efficient fuels

“There are three main areas of energy use: propulsion, which accounts for 60%, hotel loads at 30% and auxiliary equipment at 10%.”

The exploration of alternative fuel sources is high on the agenda for The World, with projects looking at fuels such as residuals (IFO-380) and biodiesel (B-100).

“The World is the first ship of its size burning only marine gas oil (MGO) rather than heavy bunker fuel (IFO-380), making for a much more environmentally friendly ship and allowing the vessel to call in ports where ships burning heavy fuel are banned,” Schneider says. “The use of biodiesel, a renewable energy source, has been a proven alternative fuel for not only diesel engines but also for gas turbines. Light cycle oil (LCO) is also an alternative to MGO for gas turbines.”

The World is evaluating the use of solar panels and vertical windmills and the optimisation of cooling water and air supply.

“There are initiatives underway or being developed for fuel cells, solar power, wind power, nuclear power and cold ironing,” he adds. “Also, the development of exhaust scrubbers and other abatement techniques will assist in the environmental challenges and fuel sourcing.”

There is no doubt energy efficiency is high on the industry agenda. Celebrity Cruises is also steaming ahead in the efficiency ratings, with Celebrity Solstice designed to be the most energy-efficient class of cruise ships at sea. Its initiatives include solar panels, LED lighting, low energy HVAC systems, silicone hull coatings and an electric propulsion system.

“Being large-scale modes of passenger transport, ships lend themselves easier to energy management,” Bazari concludes. “With activities pursued by the owners and operators voluntarily and the advent of IMO energy efficiency regulations, I believe that the maritime industry is now in a very good position.”