Page 35: of Maritime Reporter Magazine (February 2024)

PTI/PTO 30 years ago shaft generators with PTI capability kept container ships sailing at top speed. That purpose gone,

PTI/PTO is making a new comeback in more cargo shipping segments, this time for reducing emissions.

By Wendy Laursen etro? tting a shaft generator is not an insigni? - the ef? ciency of modern permanent magnet technology that cant undertaking. Around 50 tons of equip- lowers their energy consumption and to the variable speed ment needs to be installed into the engineroom drives that enable them to provide constant power over a wid- through a hole in the hull. A new section of er engine speed range.

Rshaft is usually required. This added potential is mostly evidenced in the newbuild mar-

That a few shipowners are undertaking such projects - ket where equipment suppliers are reporting increased interest

Klaveness Combination Carriers on the Ballard, along with from the cargo ship market. The speci? c fuel savings achieved air lubrication, and Berge Bulk on the Berge Olympus, along will vary depending on whether the ship has a 2-stroke main with wind-assist – is testament to technology developments engine or a 4-stroke-based electric power system, and whether and the times. it has controllable or ? xed pitch propellers. The propulsion

A power take off (PTO) shaft generator can reduce genset con? guration is important, because speci? cation of shaft gen- operation time and therefore reduce fuel consumption by mak- erators involves careful optimization of engine and propeller. ing better use of a ship’s less expensive main engine power. Propeller ef? ciency and cavitation are considered along with

Adding power take in (PTI) functionality means the system the ef? ciency of the engine over a range of power outputs.

can also act as a motor to provide the power boost needed to “We do a lot of optimization,” explains Jens Ring Nielsen, keep schedules in heavy seas or to navigate ice-infested waters Senior Technology Engineer at MAN Energy Solutions. “If without the need for overloading or oversizing the main en- you ask an engine designer about the most ef? cient way of gine. This power comes from gensets or batteries. With the ad- operating, they’ll point to one path on the engine map. If you dition of a clutch, PTI also enables a ship to run on full electric ask the propeller OEM, they’ll say another. The truth is some- mode during port maneuvering and can provide safe return to where in between.” port power in an emergency (power take home (PTH) mode). Speci? c considerations, such as whether to have a clutch

Shaft generators are bene? cial to EEDI/EEXI/CII calcula- between the shaft generator and the main engine or whether tions and can reduce fuel consumption by up to 20% thanks to to have a primary or secondary shaft installation, depend on

Berge Olypus has been retro? tted with a shaft generator

Klaveness Combination Carriers’

MV Ballard has been retro? tted with a shaft generator

Source: Berg Bulk Source: Klaveness Combination Carriers www.marinelink.com 35

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