GE and Rolls-Royce control gas turbine market

Two manufacturers dominate the marine gas turbine market: General Electric GE and Rolls-Royce.

GE’s range of marine gas turbines includes the LM500 and the family of LM2500 GTs. Newer gas turbines such as the small GE38 (recently completed ground testing) and the powerful LM6000 have not currently gained any marine sales.

GE’s LM500 is derived from the TF34/CF34 turbofan aircraft engines, developed in the 1960s/1970s, and has about 90 per cent commonality with the CF34 engine that powers the popular CRJ100/200 regional jet, an engine with more than 14 million hours of operation. The simple cycle LM500 is a two-shaft gas turbine consisting of a gas generator, a free power turbine and cold end drive capabilities. Power output is 4,570kW with a brochure specific fuel consumption of 269.5 g/kWhr.

With the exception of Norway’s Skjold-class (the only vessel with Pratt & Whitney engines), GE’s LM500s are used on all of the world’s current naval gas turbine-powered patrol boat classes. There are 100 LM500 gas turbines delivered or on order, accumulating more than 140,000 hours in marine service.

The largest recent order for GE’s LM500 gas turbines is for the Korean (ROK) Navy’s PKX patrol boats. There are two classes of PKX – PKX-A and PKX-B.

The 63m, 40-knot Gumdoksuri-Class PKX-A boats uses two GE LM500 gas turbines, each rated at 4,175kW, in a combined diesel and gas turbine arrangement. The first PKX Yoon Young-ha was launched at Hanjin Heavy Industries’ Busan, shipyard. Samsung Techwin provided 36 LM500 gas turbine modules for the PKX program.

The PKX-B patrol boats will also use LM500 gas turbines, rated at approximately 4,486kW, in a combined diesel and (single) gas turbine arrangement.

For PKX the LM500 when mounted on a marine base is 3.66m long, 1.65m high and weighs 2,779 kilograms including the inlet air collector and the exhaust gas plenum. In this arrangement power density is about 0.619t/MW. A similarly powered naval high-speed diesel would be about 3.7m long but would weigh about 16,000kg giving a power density of 3.6t/MW. The analysis can become more complex when considering gears, intakes/uptakes and bunkering but the power density advantage remains strong however the arithmetic is done.

Samsung Techwin locally manufactures selected parts of the LM500s, and assembles and tests the completed engines. GE will provide support of the gas turbine, control, and reduction gear system to Samsung Techwin, to the shipyard Hanjin Heavy Industries and Construction and the ROK Navy throughout installation, sea trials, and commissioning.

In Japan, the LM500 has been installed on the recent 22DDH Isumu-Class helicopter Destroyer, due to commission in early 2015 and has been selected for the follow on 24 DDH. The 22DDH project will be the first LM500 generator set application supplying onboard ship service electrical power for naval ships. "We are partnering with IHI whereby they will design and package the propulsion modules and electrical generator sets powered by GE's LM2500 and LM500 gas turbines, respectively," said Brien Bolsinger, GE Marine general manager.

As a packaged genset the LM500 offers 4.2 MWe and sits on a baseplate of 7.14m x 2.36m x 2.39m, offering good opportunities for installation in naval combatants. Compact diesel gensets in this power range are not currently available: The diesel gensets included in F125 and T26 offer about 3 MWe in a similar length to the LM500, but weigh around 40 tonnes.

Over the last ten years, new classes of naval ship powered by GE’s LM2500 family include the Franco-Italian Horizon and FREMM (G4), USN Independence-class LCS and LHA-8 (+), USCG Hamilton cutters, Germany’s F125, Turkey’s Milgem, and Japan’s 22 and 24 DDH.

Rolls-Royce’s current range of marine gas turbines includes three small GTs (AG9140, RR4500 and the new MT7) and the MT30.

The AG9140 (3MWe) and the RR4500 (3.9MWe) are marine variants of the Allison 501 family of engines derived from the 1950s T56 (C-130 Hercules turboprop). AG9140 is on all US, Korean and Japanese Aegis-Class destroyers, three per ship. RR4500 is installed on all three of the all-electric DDG1000 Zumwalt Class of destroyers (two per ship together with two MT30s). MP