Ship Power and sustainability

The shipping industry is seeking more and more ways to increase energy efficiency, lower operational costs, and comply with upcoming environmental legislation. The primary drivers for this are escalating fuel prices, the International Maritime Organisation’s (IMO) Energy Efficiency Design Index (EEDI) for limiting the carbon dioxide emissions from new vessels, and emissions legislation specified by the IMO and the US Environmental Protection Agency for nitrogen oxides (NOx), sulphur oxides (SOx) and particulate matter (PM) emissions.

The development of new and existing technologies is the key to Wärtsilä succeeding in offering its customers the best solutions to meet these needs. Wärtsilä’s toolbox for reducing emissions includes, for example, switching the fuel from heavy fuel oil to gas, using liquid fuels together with emission control methods, and improving vessel efficiency. Wärtsilä’s development agenda focuses on all of these elements as part of its commitment to sustainability, and to retain its leading position in this field.

Environmental solutions

To ensure environmental compliance, Wärtsilä has developed various primary and secondary emission reduction technologies. Wärtsilä’s after-treatment solutions enable optimal integration with the ship’s power train. To lower emissions of NOx, a range of catalytic reducers are available under the Wärtsilä Nitrogen Oxide Reducer (NOR) product name, while Wärtsilä Sulphur Scrubbers are available for the reduction of SOx.

To enable the further lowering of exhaust gas noise levels, Wärtsilä has successfully delivered compact silencer solutions (CSS). This modular solution allows a higher noise reduction rate without increasing the exhaust gas back pressure, which also has a positive effect on energy consumption.

Wärtsilä seeks solutions that also enable other industries to reduce their environmental impacts. For instance, Wärtsilä has co-operated with partners in the development of a High Performance Turbine Installation Vessel and a new and environmentally sound concept for offshore wind farm installation and maintenance vessels.

Emission typeEffectLegislationTechnologies
Carbon dioxide CO2 Global warming IMO’s EEDI Improved efficiency, gaseous fuels
Sulphur oxide SOx Acidification of soil and water IMO’s global sulphur limit, Sulphur emission control areas (SECA) LNG, SOx scrubber
Nitrogen oxide NOx Smog, eutrophication IMO’s global  NOemission limits (Tier I, II), NOx control areas (Tier III, NECA) Dual-fuel engines, catalytic reduction
Particulate matter PM Human health impacts U.S. EPA, regional legislations Dual-fuel engines, exhaust gas scrubber, diesel particulate filter


To reduce emissions to water, our propulsion shaft line sealing systems offer environmentally sound alternatives that prevent the leakage of oil from ships. We also offer efficient treatment systems for 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.

Gas as an enabler

The use of liquefied natural gas (LNG) in shipping has numerous benefits, both for the shipping industry and for the society at large. Wärtsilä has actively developed technologies that allow the use of gas to fuel vessels. Wärtsilä’s dual-fuel technology brings together two combustion technologies into one single product. This has a unique advantage in that the same engine can be run on either gas or diesel, thus providing maximum flexibility in fuel choice. Switching between the different operational modes can be made whilst the engine is running.

The benefits of using Wärtsilä’s dual-fuel technology to enable ships to be powered by LNG are clear:

  • Emission reductions (when operating in gas mode):
    • NOx emissions by 85%
    • SOx emissions by 100%
    • Particulates by 99%
    • CO2 emissions by 20-30%
    • No smoke
    • Reduced waste streams (liquid waste)
    • No need to use secondary emission reduction systems (and hence no consumption of reagents) to meet current and known future emissions legislation
  • Fuel flexibility to enhance power security and competitiveness:
    • HFO or MDO operation possible
    • Biofuel use also possible
    • Crude oil possible
    • Redundancy and safety

Wärtsilä is the world’s leading ship design company in the field of gas-fuelled special vessels. For LNG applications, Wärtsilä has the widest engine range in the industry. To date, more than 470 Wärtsilä dual-fuel engines capable of running on gas have been sold to 87 vessels, consisting primarily of LNG carriers. More than 50 vessels are already in operation. Wärtsilä’s gas technology provides high efficiency, even at part-load, and with very low emission levels. By using gas to power vessels, the industry will take a major step towards more sustainable shipping.

In addition to engine development, Wärtsilä has developed a complete LNG storage and fuel supply system that includes on-board bunkering facilities, known as the Wärtsilä LNGpac. This solution enables the use of gas in all vessel types.

Wärtsilä’s dual-fuel medium-speed engines have now accumulated more than 3 million running hours in both land-based and marine applications. This milestone represents a dual-fuel technology track record that cannot be matched by any other engine manufacturer. Wärtsilä’s dual-fuel engine technology provides the flexibility to switch between the use of natural gas and heavy fuel oil, light fuel oil and various other liquid fuels. This flexibility in fuel choice offers economical, safety, and environmental benefits. The solid and unique track record that Wärtsilä’s dual-fuel technology has established in LNG carriers has created confidence in the reliability of this technology also within other vessel segments. The number of opportunities for gas fuelled ships is growing rapidly and now includes several types of vessels.

Efficiency improvement

By improving overall ship efficiency, both lifecycle costs and exhaust emissions can be reduced. CO2, SOx and particulate emissions are directly linked to fuel consumption. Wärtsilä’s portfolio of solutions addresses all the necessary application areas, including automation, machinery, propulsion and ship design. By combining these solutions with a solid knowledge of customer operations and treating them as an integrated system, truly efficient ship operations can be achieved. We constantly strive to develop products and solutions that are more operationally efficient and cost-effective for the entire ship concept.

Electric propulsion offers great operational flexibility. However, electric transmission is less efficient than mechanical transmission. Wärtsilä’s patented low loss concept (LLC) lowers the energy losses in electrical transmissions to 6-7%, compared to 10-12% for traditional electrical transmission systems. The Wärtsilä LLC not only improves efficiency, but is also more compact and more redundant than traditional systems.

To enable more efficient operation of the propulsion train, Wärtsilä has introduced Variable Turbine Geometry turbochargers on 2-stroke engines. The first upgraded Wärtsilä X68-D engine equipped with a Variable Turbine Geometry turbocharger was successfully tested at the Doosan Engine Company facilities in South Korea.

Vessels designed for lower speeds and larger, more efficient propellers require engines that are optimised for lower speeds. Wärtsilä has strengthened its offering in the mid-size, low-speed engine sector by adding new 62- and 72-bore low-speed engines to its portfolio in the X-generation engine family. These are not only more efficient than the engine models they replace but, thanks to their optimised design speed, allow for more efficient propeller designs as well. These new engines offer higher propulsion efficiency, reliability, and optimised total cost of ownership to the bulker, tanker, and feeder container markets.

Milestones reached during 2011
Gas First small gas engines (Wärtsilä 20DF) delivered in 2011. The Wärtsilä 20DF engine, with a power range of 1-1.5 MW, offers smaller vessels the benefits of gas.
Gas The first marine conversion took place in which the two main engines of a product tanker, the ‘Bit Viking’, were successfully converted from a Wärtsilä 46 engine type to a Wärtsilä 50DF engine type. This was not only the first gas conversion for a marine installation, but also the first Wärtsilä 50DF engine used for mechanical propulsion, the first delivery of the Wärtsilä LNGpac, the first delivery of the new gas valve unit, and the first time a Wärtsilä DF engine has fulfilled single main engine requirements.
Gas Order received from Viking Line for the first cruise ferry using gas as fuel.
Wärtsilä SOx scrubber Order received from Algoma Central Corporation to supply complete propulsion systems with integrated scrubbers for six vessels.
Wärtsilä Nitrogen Oxide Reducer (NOR) During 2011, contracts were signed for 15 NOR units.
Compact Silencer System (CSS) During 2011, contracts were signed for 11 CSS units.
High performance nozzle 10 high performance nozzles have been sold.
Energopac 6 energopac rudders sold. The Wärtsilä Energopac is a rudder solution designed to improve a ship’s efficiency.
Low Loss Concept (LLC) 70 LLC units were sold by the end of 2011.


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