Engine Technologies Auxiliary Systems Optimization

Auxiliary systems optimization consists of assessing energy consumption and production of auxiliary systems so that save energy and fuel, since auxiliary systems are designed to support high loads (80- 100%) from main engines and they usually work at low loads (20-65%). Auxiliary systems optimization is achieved through speed control of pumps and funs, control strategies of cooling water systems, retrofitting of heat exchangers, management of auxiliary energy distribution and consumption, and others. This measure can be applied to any type of vessel, offers a reduction potential of 1-5% of the total vessel fuel consumption and has an implementation cost of 10,000 to 150,000 USD depending on whether it is a new building or retrofit (GloMEEP, n.d.-d; IMO, 2015).

Engine De-Rating

Engine de-rating consists of reducing vessel maximum speed and MCR in order to optimize working engine load point and reduce fuel consumption, as vessels nowadays have reduced their service speed, and consequently, main engines do not work at their designed load levels. Engine de-rating can be done by several methods, which vary in cost, flexibility and effort required; allows a speed decrease of 10-15% and is a reversible solution. This measure can be applied to any type of vessel, provides a reduction potential of 2-10% of main engine total fuel consumption and has an implementation cost of 60,000 to

Chapter 6. Upcoming Air Pollution Regulations and Technical Improvements

3,000,000 USD depending on the method and engine de-rating magnitude (GloMEEP, n.d.-h; IMO, 2015).

Engine Performance Optimization

Engine performance optimization consists of enhancing cylinder pressure balance and setting maximum combustion pressures closer to rated values so as to allow more efficient combustion, which decreases fuel consumption and makes engines cleaner. Nowadays, regular testing and calibration of main engines is done manually, although, desired results are not achieved. For this reason, automatic engine performance optimization is starting to be implemented on board new vessels, and is done by adjusting and optimizing fuel injection timing, maximum combustion pressure and combustion pressure. This measure can be applied to any two-stroke engine, offers a reduction potential of 1-4% of total vessel fuel consumption and has an implementation cost of 3,000 to 7,000 USD depending on the engine type and whether it is a new building or retrofit (GloMEEP, n.d.-i; IMO, 2015).

Waste Heat Recovery Systems

Waste heat recovery systems are designed for using heat from exhaust gases to generate electrical energy, steam or hot water. These systems are addressed to main propulsion engines, even tough, have begun to be introduced into auxiliary engines. Heat recovery systems use exhaust gas boilers, gas turbines or steam turbines to recover and process the heat from exhaust gases, and as a consequence, reduce fuel consumption and improve efficiency of main and auxiliary engines. This measure can be applied to any type of engine that operates at high load, provides a reduction potential of 3-8% of fuel consumption for main propulsion engines and 1-5% for auxiliary engines, and has an implementation cost of 5,000,000 to 9,500,000 USD for main propulsion engines and 50,000 to 75,000 USD for auxiliary engines (GloMEEP, n.d.-j, n.d.-aa; IMO, 2015).

Auxiliary Engine Load Optimization

Auxiliary engine load optimization consists of enhancing load levels of auxiliary engines used to generate electrical energy to supply vessel electric systems, and therefore, decrease their fuel consumption. The number of auxiliary engines fitted on vessels ranges from 2 to 6 based on their layout, mechanical or electrical, and vessels commonly run with additional auxiliary engines because of redundancy. Auxiliary engine load optimization is achieved through raising their mean load level and reducing the number of auxiliary engines operating. This measure can be applied to any type of vessel, offers a reduction potential of 0-20% of auxiliary engine fuel consumption and has no direct implementation cost (GloMEEP, n.d.-r).

Shore Power

Shore power consists of supplying vessels when berthed with electrical energy from shore grid power so that replace energy from auxiliary engines, and therefore, eliminate exhaust gas emissions and local noise while at harbour. However, shore power requires relatively expensive installations on board and on shore owing to the necessity to improve the grid capacity, frequency convertors and sophisticated power connectors. For this reason, shore power supply for vessels with large electric power needs has not been widely established. This measure can be applied to any type of small vessel, provides a reduction potential of 50-100% for the auxiliary engines at harbour and the implementation cost depends on the type and size of vessel and plant design (GloMEEP, n.d.-w; IMO, 2015).

Hybridization

Hybridization consists of installing batteries on vessels in order to cover entire or partial electrical demand of on board systems. Batteries provide additional power when electrical demand is high and are charged when electrical demand is low using the surplus of energy produced by engines, as a result, smaller engines can be installed and constantly run within optimal loads improving their performance. Hybridization presents three degrees: full-electric vessels, which are equipped only with batteries that provide propulsion and auxiliary power; plug-in hybrid vessels, which are fitted with combustion engines and batteries that are charged by shore power; and conventional hybrid vessels, in which batteries are charged by on board engines. This measure can be applied to vessels with large load changes, for example ferries, OSV and tugs; offers a reduction potential of 15-30% of the total vessel fuel consumption depending on vessel consumption and operating characteristics; and has an implementation cost of 600,000 to 2,000,000 USD for conventional hybrid vessels, 1,800,000 to 3,000,000 USD for plug-in hybrid vessels and 4,800,000 to 6,000,000 USD for full-electric vessels (GloMEEP, n.d.-q; IMO, 2015).

6.5.2 Hull and Propulsion Technologies