APRIL 7, 2016 — A 45,000 cum LNG carrier to be built by Chinese shipbuilder China Merchants Heavy Industry Co., Ltd. for Saga LNG Shipping is to be equipped with a permanent magnet (PM) shaft generator, allowing the vessel to gain greater efficiency over its entire speed range.
The shaft generator will be supplied by Helsinki, Finland, headquartered The Switch, a specialist in megawatt-class PM machines, as part of a complete energy efficiency system being delivered by WE Tech Solutions (WE Tech) of Finland to Saga LNG Shipping.
"The optimized PM shaft generator system using WE Drive allows unprecedented levels of energy efficiency in the marine industry," says Mika Koli, Business Development Manager of The Switch. WE DriveTM is WE Tech's variable frequency drive for shaft generator applications.
Using the active front-end low harmonic drive technology of WE Drive, the PM shaft generator can operate over the full main engine speed range while generating electricity for the vessel's electrical network with high efficiency. This feature is particularly advantageous in electrical part loads, which is the normal electrical load condition in any ship.
Along with The Switch PM shaft generator and WE Drive, WE Tech will also deliver its efficient power distribution solution that provides the vessel's electrical network with up to 1,200 kW of electrical power in Power Take Out (PTO) mode. The delivery also features the Power Take In (PTI) mode for Take Me Home, whereby the WE Drive is used as an auxiliary propulsion drive when the main engine is not in operation. Additionally, the solution utilizes the common DC-link in the WE Drive™ to enable energy-efficient DC power distribution for the bow thruster.
The high-speed PMM 500 marine shaft generator will be connected to the PTO shaft of the reduction gear in the propulsion line.
The Switch offers PMM 500 shaft generators in various power ranges from 0.5 to 4 MW at speeds of up to 2,000 rpm to best adapt to various requirements.
"Over the past few years, we've been developing our solution together with The Switch and other close suppliers," says Mårten Storbacka, Managing Director of WE Tech Solutions. "The main advantage of permanent magnet technology is that it significantly increases energy efficiency. Depending on how you calculate it, fuel savings are approximately 20-30%. Since this technology lowers the need for installed power on a ship, energy generation and weight are reduced significantly, thereby lowering fuel consumption and the need for maintenance."