GE Turbines Offer Hybrid Solutions - Maritime Propulsion

Posted - By Keith Henderson at May 10, 2012 07:36 - Maritime Propulsion 

As more and more ship owners and builders are evaluating the feasibility of using hybrid electric propulsion systems for existing or new build ships, GE is offering hybrid systems for military and commercial applications based on its LM series gas turbines using electric motors and drives, to reduce noise and emissions through improved fuel economy.


Caption: A GE LM2500 module with power out put of 25 MW
Image credit: General Electric
GE has a wide experience of hybrid systems, acting as systems integrator, GE is able to team with other industry suppliers to provide all electric propulsion solutions. The common factor for the successful application of hybrid systems is that the usage cycle is carefully studied and an appropriate combination of engines selected to operate efficiently at the required outputs.

A particularly successful combination with gas turbines is the CODAG or CODOG arrangement where diesel engines are employed at low output with the gas turbine(s) only used to produce boost power.

As the cost of fuel increases, such solutions are not limited to newbuilds, repowering of existing vessels can also provide tangible financial benefits. For example the cruise ship Radiance of the Seas was originally built with twin GE LM2500 gas turbines for propulsion and generation plus a Paxman 18VP185 auxiliary generator however it was later decided to add an 11.2 MW Wärtsilä 16V38B generator so that the gas turbine(s) would not have to be used at low power outputs where their efficiency is not optimal.

Some of the more modern designs of frigates use have two shafts powered by electric motors powered by diesel gensets with a single gas turbine available for extra power, added using a mechanical drive via clutches and a splitting gearbox to each shaft.

In the future wider use of fuel cells can replace diesel engines to provide further reductions in exhaust, noise and vibration emissions.

Caption: The hybrid twin shaft electric propulsion configuration with mechanical
gas turbine boost as used on the current FREMM class frigates
Image credit: Renk AG
 
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