Page 72: of Maritime Reporter Magazine (June 2012)

GE Marine offers hybrid electric sys- tems for military and commercial marinecustomers based on its LM aeroderivative gas turbines, motors and drives, to help reduce noise and improve fuel economy. Hybrid electric arrangements cross-con-nect the ship service power system with the propulsion system by placing an elec-tric motor and its associated motor drive in the drive train. At lower speeds, the propulsion system, such as engines, areturned off and the electric motors provide cruising power. GE has provided components on seven gas turbine hybrid or electric powered ship classes in service or under construc-tion, including the propulsion system onthe United States Navy?s LHD 8 USS Makin Island. GE offers a family of LM2500 gas turbines from 22 to 32 MW for twin or single gas turbine hybrid plants. In addition to the LHD 8-classships, GE LM2500s are used on a variety of hybrid propulsion plants, including the German Navy?s F124 and F125 frigates, and the Italian and French FREMMfrigates. In new designs ? particularly frigates from 3,000 to 7,000 tons ? a hy- brid electric arrangement is designed toimprove efficiency. The traditional COm- bined Diesel Or Gas turbine (CODOG)or COmbined Diesel And Gas turbine (CODAG) frigates have two gas turbines and two diesels for propulsion and typi- cally four diesels for ship service power. With GE?s hybrid electric arrangement, the two propulsion diesels can be elimi- nated and replaced by electric motors.This arrangement can reduce ship con-struction, propulsion equipment, andmaintenance costs while helping reducenoise and improve combat capabilities. GE?s LM2500 gas turbines, for in- stance, can be applied in a dual gas tur- bine hybrid arrangement versus a single gas turbine configuration to provide the lowest technical, cost, schedule and op- erational risk. If incorporated into an ex- isting LM2500 CODOG ship design, GEbelieves a dual gas turbine configuration requires the fewest ship modifications such as changes to bulkheads, uptakes, stability, the second platform level, and the deckhouse. GE?s dual gas turbine system configu- ration has two completely independent shaft lines to provide significant redun- dancy and survivability. 72Maritime Reporter & Engineering News TECHNICALPROPULSION UPDATE GE Gas Turbine Hybrid Electric Drive ArrangementsMR June12 # 9 (65-73):MR Template 6/12/2012 3:34 PM Page 72