GE Energy and Mitsubishi Heavy Industries have signed a memorandum of understanding to co-develop what they hope will be the next generation steam turbine for use in gas turbine combined-cycle power plants. Steam turbines remain a backbone of the power industry, playing a part in generating more than 80% of the world’s electricity. Much of the current demand for steam turbines is being driven by the strong global interest in natural gas-fired, combined-cycle power plants, so development of a specialised ST is viewed by both companies as an essential step in meeting customer demands for increased combined-cycle efficiency and performance.

After negotiation and execution of definitive agreements, the co-operative venture between these two former competitors has the goal of designing and developing the world’s most advanced ‘best of breed’ combined cycle steam turbine, which the two companies would then include in their respective product offerings.

The objective is to make best use of the best available technologies from both companies, but neither company is able to specify at this stage exactly what technologies that encompasses. The two companies’ products have developed in different ways, using different steam arrangements, blade profiles and so on. GE has tended to go the impulse route, but has produced some high-reaction designs recently. The structure of the R&D effort will be one of the matters to be decided during the next round of negotiations, along with authorisations, intellectual property rights, structure guidelines, rules of engagement and so on. Some meetings have already taken place and are pushing on well, according to GE.

GE has a long history of partnering with other suppliers to accelerate the pace at which advanced technology products are brought to market. ‘GE and MHI each have developed extensive experience in steam turbines over many decades, but have identified significant mutual product performance benefits in the co-development of the next generation combined-cycle steam turbine’ says Steve Bolze, president of GE Energy’s Power & Water business. And GE’s experience to date has worked well, for example in the nuclear collaboration with Hitachi, which resulting in GE-Hitachi Nuclear Energy. It helps accelerate the pace of development and makes the most of portfolio technologies that both parties possess; it spreads the cost burden of R&D and gains maximum value from new product introductions.

Steam turbine technology has been maturing now for 100 years, and improvements are difficult to come by. Even incremental performance enhancements require significant investment in new technology. By sharing in the development, GE and MHI will look to share best practices and development activities to bring a next generation steam turbine product to market faster than either party could individually achieve.

At a later stage, they may consider co-developing a steam turbine for nuclear power applications. GE is anticipating a potential increase in demand for large steam turbines for nuclear power projects as that sector of the energy industry continues to generate renewed interest.

The HEAT is still on

GE already has a specialised combined cycle ST in its HEAT (High Efficiency Advanced Technology) offering, a project that started in 2002 with the object of combining a new ST with gas turbine technology to improve combined cycle plant efficiency. This development came to fruition two or three years ago, and the new turbine is likely to incorporate many of the features of what was GE’s first foray into high reaction technology. Currently there are seven of them in operation around the world. They represented something of a departure from GE’s established technology which is strongly in impulse turbines.

HEAT steam turbines incorporate numerous design advances over earlier GE machines including high-reaction drum rotor construction, 2400 psia/565 bar pressure capability, optimised seal clearances, low pressure-drop valve designs, longer-bladed and higher efficiency last-stage bucket designs and advances in materials technology.