Terms frequently used in publications by Wärtsilä’s Power Business
Airshed = The local area around a power plant whose ambient air quality is directly affected by the emissions of the plant. The size of the relevant local airshed will depend on plant characteristics, such as stack height, as well as on local meteorological conditions and topography. In some cases airsheds are defined in the local legislation or by the relevant environmental authorities.
Baseload = Power plants running for more than 8,000 hours/year, i.e. generating power for continuous use.
Biofuel = Biofuels are a large and relatively unexplored source of energy worldwide. They are derived from forest, swamp and agricultural biomass, and from organic solid, liquid and gaseous biowastes recoverable from municipal, agricultural and industrial processes.
Biopower = Electrical or thermal power, or both, produced by a biofuel-fired plant. Biofuels are considered renewables; therefore biopower is viewed as a “clean” technology.
BioGrate = Combustion technology patented by Wärtsilä and on which Wärtsilä BioPower’s small power plant technology is based. BioGrate is especially suitable for burning wood residue, bark and sawdust.
Boiler plant = The plant entity which includes the boiler and all the necessary equipment and auxiliary components needed for operating the plant process.
Bow thruster = A transverse thrusters mounted in the bow of a ship to make manoeuvring easier in harbours.
cgt (compensated gross tonnage) = The compensated tonnage of a ship, i.e. the ship’s volume adjusted (compensated) by a factor to render the amount of work at the yard equivalent for different types and sizes of ship.
CIPS = Coastal and Inland Propulsion System. A tailor-made propulsion system with small fixed pitch propellers (diameter below 3.5 m) suitable for inland navigation vessels, fishery vessels, coasters and luxury (mega) yachts.
CO2 = Carbon dioxide. A component in an engine’s exhaust gases formed when fossil fuels are burned. The most significant greenhouse gas in the atmosphere; it prevents thermal radiation entering the atmosphere from being reflected back into space.
Cogeneration = The simultaneous generation of electricity and heat. Also called Combined Heat and Power (CHP). This method raises total efficiency to above 90% since the heat produced by power generation is recovered and used, for example, in industrial processes or to supply district heat.
Combined cycle technology = The use of two different power generation processes, e.g. fuel engines and steam turbines, in the same power plant. The second process utilizes the heat recovered from the first.
Combined heat and power = CHP = A means of recovering and using the heat produced as a by-product of the electrical generation process.
Common rail = A method of fuel injection that eliminates the principle of one pump/cylinder. The common rail is constructed from a series of accumulators interconnected by small-bore piping. The injection pressure is adjusted as desired and the injection timing (start and stop) controlled electronically. Wärtsilä has used common rail technology to develop the “smokeless engine”, which also reduces NOx and CO2 emissions.
Controllable pitch propeller (CPP) = A propeller whose pitch can be controlled (changed) by rotating the blades with a hydraulic or electro-mechanical system in the propeller’s hub.
DCC (Diesel Combined Cycle) = Technology utilizing both the shaft output and thermal output of a diesel engine. The thermal output is used to drive a steam turbine, for example.
Decentralized power plant = A small local power plant for small towns, communities or industrial processes.
Deep Sea Seals (DSS) = The trademark for Wärtsilä Propulsion seals.
DeNOx = Secondary emission reduction technology for emissions of nitrogen oxides. Commonly used technology is Selective Catalytic Reduction (SCR) system.
DWT (dead weight tons) = The difference between the displacement and the lightweight of a ship, i.e. the combined weight of its cargo, passengers, crew, stores, fuel and other liquids.
DWI (Direct Water Injection) = A method in which water is injected into the engine cylinders prior to fuel injection in order to reduce nitrogen oxide emissions. Direct water injection reduces the combustion temperature and therefore the formation of nitrogen oxides.
Economizer = Additional heat recovery equipment that lowers the flue gas temperature, reducing heat losses and improving efficiency.
Efficiency (power generation) = The ratio between the input fuel energy and the power produced. The total efficiency of a power plant means the amount (%) of total fuel energy that can be converted into electricity and heat.
Efficiency rudder = The Efficiency Rudder is a horn rudder that is integrated with the propeller through a fixed streamlined torpedo. This integrated concept reduces fuel consumption, vibration and noise levels compared to a traditional design.
Electrical efficiency (engine) = The amount (%) of total fuel energy that can be converted into electricity.
Electrical efficiency (power plant) = In simple cycle, the ratio between the input fuel energy and the electrical energy produced.
EnviroEngineTM = A smokeless dieselelectric propulsion package developed jointly by Wärtsilä and Carnival Corporation for marine vessels. Combines the use of common rail and DWI technologies. Since both methods are electronically controlled, the EnviroEngine offers an optimized combination of engine efficiency, smoke emissions and NOx emissions.
Eutrophication = A process by which pollution from such sources as sewage effluent or leachate from fertilized fields causes a lake, pond or fen to become overrich in organic and mineral nutrients, so that algae grow rapidly and deplete the oxygen supply.
Face seal = A non-polluting seal (e.g. Wärtsilä Coastguard) that eliminates oil loss from a ship’s outboard seal, even when this is fouled or badly damaged. The face seal is suitable either for retrofitting to existing vessels or for use on new tonnage, especially cruise vessels, tankers, bulk carriers, RoRo vessels and offshore applications.
FGD = Secondary emission reduction technology for emissions of sulphur oxides. Examples include alkali scrubbing and semidry FGD using quicklime or calcium carbonate scrubbers.
Fixed pitch propeller (FPP) = A monoblock (cast in one piece) propeller optimized for only one operating condition.
Four-stroke engine = An engine in which the pistons complete their power stroke every second crankshaft revolution.
FSN (Filter Smoke Number) = A unit defining the amount of smoke. When measuring, exhaust gas is fed through a special filter element, the colour of which is then analyzed optically.
Fuel cell = Fuel cells are electrochemical devices that convert the energy of a fuel through a chemical reaction directly into electrical energy and heat. The basic physical structure or “building block” of a fuel cell consists of an electrolyte layer in contact with a porous anode and cathode on either side of it.
Fuel cell stack = A fuel cell stack is a multilayer sandwich of fuel cells and interconnecting plates. The plates function as channels for distributing fuel gas and oxygen to the cells and also as an electrical conductor to couple the repeating cells in series. Piling a sufficient number of cells in series raises the stack voltage and power to the optimum level. See also Solid oxide fuel cell.
Gas compression = The raising of gas pressure and density for further processing. This makes it possible to use smaller storage tanks or pipes to transport a given quantity of gas.
Gasification = The production of fuel gas from biofuel for heat and/or power generation. This is a relatively new technology that is currently being developed and commercialized.
GT (gross tonnage) = The gross tonnage of a vessel, i.e. its total enclosed volume.
GTCC (Gas Turbine Combined Cycle) = Technology utilizing the shaft and thermal outputs of a gas turbine.
HFO = Heavy fuel oil
High-powered special vessels = Passenger or naval vessels able to travel at high speeds.
High-speed engine (diesel/gas) = An engine running at speeds over 1,200 rpm (revolutions per minute).
Hot combustion = A method that raises the temperature of the engine exhaust gases by reducing the air intake and isolating the combustion chamber. This increases total efficiency and enhances the engine’s suitability for combined cycle technology.
IMO = The International Maritime Organization.
Independent Power Producer (IPP) = A private corporation producing electricity for sale on a national grid. Also an IPP power plant.
JMT (Japan Marine Technologies) = Trademark for lip seals.
Lambda control = Lamba (2) represents the current air volume divided by the stoichiometric air volume. Lambda control refers to the control of the air volume in the combustion process.
Lean-burn gas engine = A gas-fired engine in which the gas-air mixture in the engine’s cylinders contains substantially more air (roughly double) than required for complete combustion of the gas. The over-abundance of air achieves high output and efficiency combined with low nitrogen oxide emissions.
Licensee = A company authorized to manufacture under licence and that pays royalty fees on the products sold. Wärtsilä’s low-speed Sulzer engines are mainly manufactured under licence.
Lip seal = Multi barrier type of sealing system (e.g. MKII). Applicable to any size or type of vessel. Highly resistant to wear and fouling.
Load management = Flexible method of meeting varying demand for power, e.g. producing more energy when required.
Low NOx technology = A method for reducing nitrogen oxide emissions that also raises engine efficiency. Emission levels are reduced by regulating the combustion temperature in the cylinders and the duration of fuel injection.
Low-speed engine = An engine running at speeds below 300 rpm.
Medium-speed engine (diesel/gas) = An engine running at speeds of 300-1,200 rpm.
Multi-fuel engine = A Wärtsilä engine running on both gaseous and liquid fuels. (Engines denoted DF and GD are multifuel engines).
Multi-purpose container carrier = A freighter carrying primarily containers but also able to transport other unitized cargo.
NOx = Nitrogen oxides (NO and NO2). Products formed during the combustion of nitrogen in both the fuel and combustion air. Nitrogen oxides contribute to local eutrophication and acidification.
NT (net tonnage) = The net tonnage of a vessel, i.e. the volume of its payload spaces.
O&M = Operations and Maintenance.
OEM = Original Equipment Manufacturer.
Offshore = Industrial activity at sea, e.g. drilling and pumping at an oil or gas well. Operations agreement = Operations & Maintenance (O&M) = Full performance and operational responsibility for the plant, its engines and auxiliary systems.
OpExS (Operative Excellence System) = This system, which covers all Wärtsilä’s operations, aims to generate added value for Wärtsilä’s various stakeholders. The system addresses issues including quality, the environment, occupational health and safety, continuous improvement process and selfassessment.
Orimulsion® = An emulsion of Orinoco bitumen and water produced in Venezuela.
Panamax vessel = A vessel whose main dimensions (beam/length/draught) are limited to enable the vessel to negotiate the Panama Canal.
Post-panamax vessel = A vessel too large for the Panama Canal. Generally refers to cruise ships and large container ships.
Propulsion package = The propulsion train used to drive a ship (propeller, reduction gear, engine, etc.).
Propulsor = A system used to propel a ship e.g. propeller, thruster.
Pyrolysis = The production of a fuel gas which can be processed as oil and which is combustible in boilers or diesel engines. This is still at the R&D stage although pilot plant projects exist.
Reduction gear = The core function of a reduction gearbox is to reduce the main engine speed to the optimum propeller speed. Wärtsilä gears have been designed to meet the highest standards of operational efficiency and reliability with low noise and vibration.
RoPax vessel = Combined RoRo and passenger ship, a ship equipped with large Roro decks and limited passenger facilities.
RoRo vessel = Roll-On/Roll-Off, a ship designed for carrying vehicles and wheelbased cargo, which are driven onboard and ashore.
Selective Catalytic Reduction (SCR) = A method to reduce NOx emissions using a catalytic converter fitted after the engine. The catalytic converter requires the addition of an ammonia or a urea solution to the exhaust gases.
Semi-submersible vessel = A vessel designed to be partially submerged to perform a specific task (e.g. semi-submersible oil or gas drilling rigs).
Service agreement = A service agreement covers all aspects of maintenance and service for optimizing a power plant’s lifecycle. This can include everything from parts supply and daily assistance, inspection and maintenance to implementation of agreed performance targets and even complete operation & maintenance packages for the installation.
Shaft efficiency = The ratio between the mechanical power measured on the engine shaft and the chemical power of the input fuel.
Shaft output = The power output developed by the engine’s crankshaft.
Simple cycle = Power generation using only a thermal power plant.
SO2 = Sulphur dioxide. Formed by the combustion of sulphur when burning sulphur-containing fuels. Sulphur dioxide contributes to acidification.
SOFC (Solid oxide fuel cell) = The fuel for a SOFC can be hydrogen, natural gas or diesel. Fuel cells offer very low emissions, high electrical efficiency and outstanding reliability. They are very suitable for the production of power in decentralized stationary (CHP) and marine applications. See also fuel cell.
Steerable thruster = A 360 degrees rotatable propulsor with FPP or CPP, which applies thrust in any direction and thus achieves superior manoevrability. Steerable thrusters can be used for both offshore (dynamic positioning) and seagoing (freerunning) applications.
Stoichiometry = Stoichiometry is the branch of chemistry that determines the relative proportions in which atoms or molecules react together to form chemical compounds. Stoichiometric air is the volume of air at standard conditions required to completely combust one unit of fuel with no oxygen left over.
Technical water = Fresh water (not potable), for instance evaporated water.
TEU (Twenty-foot equivalent unit) = 1 TEU is equivalent to the capacity of one 20-ft long container; hence a 12,500 TEU containership can in principle carry 12,500 containers. The TEU takes no account of a container’s weight.
Traditional fuel injection = Mechanically controlled fuel injection. Each engine cylinder has its own fuel injection pump and all the pumped fuel is fed directly into the cylinder.
Turbocharging = The pressure of the air fed into the cylinder is raised using the energy in the engine’s exhaust gas. This increases the amount of air in the cylinder, allowing injection of a higher quantity of fuel for greater output.
Turnkey power plant = A power plant delivered to the customer ready for operation.
Two-stroke engine = An engine in which the pistons complete their power stroke every crankshaft revolution.
ULCC tanker = Ultra Large Crude Carrier, an ocean-going supertanker designed to carry extremely large amounts of crude oil(>300,000 dwt).
VLCC tanker = Very Large Crude Carrier, an ocean-going supertanker designed to carry large amounts of crude oil(>200,000 dwt).
Waterjet = A propulsor that uses a pump to accelerate waterflow. The momentum generated by the acceleration of the flow results in a force that propels a ship.
WPPP = Wasa Pilot Power Plant. This power plant has been utilized as a test plan for various fuel types and environmental control technologies such as NOx and particulate abatement as well as flue gas desulphurization.
