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Ship Power and sustainability

The need for operational flexibility, energy efficiency, and emissions reduction increases the complexity of maritime solutions, resulting in increased demands during each phase of the installation's lifecycle. Wärtsilä Ship Power's strategy is to be the most valuable business partner in each lifecycle phase.

Operational flexibility

For vessel types requiring considerable operational mode variations, flexible machinery arrangements have been specified for decennia. Vessel speed is increasingly used as a mean of adapting fleet capacity and is replacing constant speed operating, which in turn means that more vessel types have a need for flexible operating arrangements.

Machinery solutions have traditionally focused mainly on achieving the best performance at a specified design point. However, enhanced flexibility requires good performance from the installation over a much wider operating range. Electric and hybrid solutions provide a flatter vessel efficiency curve at the expense of more complex solutions. Each ship is built for a dedicated purpose making it unique and as such the prototype of itself. To limit risk, yards and owners tend to be very conservative in introducing new concepts. Wartsila is stepping into this opportunity by offering integrated solutions for which performance guarantees can be given, thereby lowering the threshold for yards and operators to implement more sustainable solutions.

The electronically controlled RT-flex engines offer merchant vessels maximum flexibility within mechanical propulsion solutions. RT-flex engines can be operated at 10% of the nominal speed, and the electronic control enables the engine efficiency curve to be easily adapted to operational requirements.

Continuously rising energy consumption is driving fuel prices up. Prior to the first maritime emissions legislation entering into force, seaborne transportation typically used the lowest remaining residue from crude oil distillation. Fuel composition has a direct impact on some emission types, and several emissions reduction technologies place requirements on the fuel. However, increased requirements on liquid fuels result in higher fuel costs and the increased cost of traditional fuels has decreased the price gap between these and alternative energy sources. Already today, natural gas can result in a lower total cost of ownership, depending on the emission limits that have to be achieved. Bio-fuels and high viscosity fuels may also become economically attractive solutions.

Energy efficiency

Many Wärtsilä products offer the highest efficiency in the market. Full scale measurements of the electrical losses from Wärtsilä's electrical power distribution system have shown values that exceed even our own expectations. In order to minimise electrical distribution losses for larger installations, Wärtsilä is currently scaling up its low loss concept by creating a variant for medium voltage as well. The power range of this solution will cover the demands of the largest cruise vessels.

The Wärtsilä Energopac is another example of a market leading component. Energopac is a rudder solution, which minimises the drag of the rudder by streamlining the water flow from the propeller to the rudder. Full scale measurements for this project have also exceeded expectations.

Wärtsilä Energopac

If quantum leaps in operational efficiency are to be made, improving the performance of individual products is not enough. In order to minimise safety margins between components, and to match the performance characteristics of the different components in the power train, an integrated approach is necessary. But it all starts with the propulsive power demand, which comes from the design of the vessel. Here again, Wärtsilä's involvement in ship design enables the achievement of truly optimised solutions.

Having a properly designed installation does not guarantee the vessel having the most efficient operation. The complexity of installations has increased the number of parameters that influence performance, making it more difficult to achieve optimal operation of the vessel. Therefore, Wärtsilä has introduced the Wärtsilä Econometer, which measures actual performance and provides the crew with real time advice on how to operate the machinery more efficiently. Further steps are under development in this direction with Wärtsilä 3C, the Wärtsilä control and command centre.

To make sustainable shipping a more achievable goal, Wärtsilä continues to challenge the industry with innovative conceptual designs that provide operators and owners with a vision for the specifications of more efficient vessels in the future. A large number of these suggestions have been collected and published in Wärtsilä's energy efficiency catalogue.

An innovative conceptual design combining several efficiency optimisers

Emissions reduction

Sea-born transportation competes with road, rail and air freighters. Because shipping is by far the most efficient form of transportation, the number of ships in operation worldwide has a significant impact on global emissions.

The existing nitrogen oxide (NOx) emission requirements set by the IMO will be tightened as of January 2011, a change known as IMO TIER II. Tier III, which comes into force in 2016, will require an 80% reduction in NOx emissions from current levels. Unlike TIERs I and II, the TIER III requirements for NOx emissions will only be applicable in designated areas (NECA).

All Wärtsilä engines are IMO Tier II compliant and feature competitive fuel consumption performance. As the Tier III emission restrictions will be different inside and outside the designated areas, and because lowering NOx emissions has a negative impact on fuel efficiency, a switch on - switch off solution is favoured. This allows vessels to meet emission requirements in the most efficient way, depending on where they are actually sailing. A number of similarly flexible concepts have been defined. The selection of the best concept is a project specific evaluation, and one that depends on the time the ship is operated inside and outside the emission control areas, and on the types of fuel available. Mathematical models that provide support for comparing alternative solutions based on the project specific mission profile are available.

To meet sulphur dioxide (SOx) emission requirements, operators have a choice between primary and secondary methods. Wärtsilä engines are designed to operate on any fuel sulphur content. Exhaust gas scrubbing is an alternative solution for reducing SOx emissions. The Wärtsilä sulphur oxides (SOx) scrubber is the first of its kind to be granted the Sulphur Emission Control Area (SECA) Compliance Certificate by the classification societies Det Norske Veritas and Germanischer Lloyd.

Secondary Nitrogen Oxides Reducer (NOR) equipment, fulfilling the most demanding NOx emission requirements, has been successfully applied for over a decade. Wärtsilä has added NOR equipment to its own portfolio, thereby ensuring optimal integration of the engine and NOR. The precise tuning of the engine and NOR results in better performance and lower cost, as well as minimises the need for additional measurements and improving dynamic behaviour. Because the engine and catalyst characteristics are tuned to work as an integrated system rather than being loose components installed in series and because the control system is based on the same platform, proper communication between engine and NOR is ensured.

In addition to the existing legislation for NOx and SOx emissions, the IMO MEPC is developing legislation to control greenhouse gas (GHG) emissions from ships. The maximum allowable GHG emission levels will be defined according to the vessel's transportational performance (capacity * speed). Wärtsilä's lean burn gas engines emit 20 to 30% less GHG compared to diesel engines, thus enabling the design of vessels which would not be possible with diesel engines.

Wärtsilä has developed a number of concepts, which improve total ship efficiency and enable the use of natural gas for powering ships. Our aim is to be at the forefront of all environmental and sustainability initiatives. The main drivers for the development of Wärtsilä solutions are future emissions legislation, fuel availability and price fluctuations, as well as increasing customer needs for more complete solutions rather than separate products. Our technology development is focused, therefore, on improving efficiency across a wide front that incorporates multifuel solutions and systems integration. Compliance with regulations is a natural starting point for all our product development.

To reduce emissions to the water, our sealing systems offer environmentally sound alternatives that prevent the spilling of oil from ships into the environment. We also offer efficient treatment systems for sludge and bilge water.

The Wärtsilä ballast water treatment system is based on the ultra violet principle to avoid the use of chemicals that end up in the sea. This intelligent design not only has minimal internal power consumption, but also has a very low pressure drop. This minimises the additional energy consumption from the ballast water pumps.