Turbine manufacturers continue to upgrade their products with technology enhancements to meet market demands for more flexibility and higher efficiency. Suppliers for combined cycle power plants outlined several of those advancements during POWER magazine’s ELECTRIC POWER Conference + Exhibition in Nashville, Tennessee this week.

Executives from Mitsubishi Hitachi Power Systems America (MHPS), Siemens, and GE Power talked about their companies’s work during a March 20 session on “State of the Art Turbine Technology,” which focused on the rapidly evolving market requirements for power generation. All three of the session’s speakers noted how the rise of renewable energy is impacting their work, as power generators seek equipment that will allow for better integration of renewables into the transmission grid through flexibility and efficiency gains.

Carlos Koeneke, vice president of plant engineering for MHPS America, noted the work his company has done in Asia, particularly for Kensai Electric Power Co. The company’s turbines, including the M501J model, are in use at several power plants, including at Kensai’s Himeji No. 2 power station in South Korea. MHPS’ M701J gas turbine is installed at Tokyo, Japan’s Kawasaki power station.

Enhanced Cooling

“We are working on enhanced cooling for our turbines, along with progressive temperature increase,” Koeneke said. He talked about the company’s next-generation closed air cooling system, which provides for higher inlet temperatures while also increasing generation efficiency, which today has moved near 65%.

“We also need to understand the risks of the introduction of new technology,” Koeneke said, presenting a list of problems MHPS has identified that could accompany improvements, such as blade cracking. “We’re working to minimize those risks. We’re in the business of debugging gas turbines.”

David McDeed, senior product manager for MHPS, told POWER in a recent interview that “In 2017, MHPS announced the introduction of a gas turbine capable of 400 MW simple cycle, and 575 MW and 64% efficiency combined cycle, the biggest, most efficient to date. This turbine is the continuation of a goal we were the first to set, in 2004, to get the gas turbine combined cycle to 65% efficiency. This turbine is another evolution toward that goal.”

Higher Efficiency

Koeneke, responding to a question about how it seems turbine manufacturers are in lockstep when it comes to their efficiency percentages, said all companies are simply responding to what the market demands. Gennadiy Afanasiev, head of design execution engineering at Siemens and another panelist at Tuesday’s session, noted that each percentage-point increase in efficiency equates to “millions of dollars” in cost savings for power generators. Christopher Corron, a GE Power product manager who also was part of the session, said that any look at performance improvements should include “efficiency in terms of cost savings.”

Eric Gebhardt, GE’s vice president of thermal engineering, has repeatedly said—even as recently as a few months ago—that GE’s turbines are efficient enough to cut “$3.5 million” off the cost of operating a combine cycle plant each year.

Afanasiev, who has supported Siemens’ global network of gas turbines and holds a dozen patents and applications in gas turbine technology, talked about his company’s rigorous testing and validation process for its turbines. He said the company will build and test advanced combustion turbine units at a Duke Energy facility in Lincoln County, North Carolina, beginning in early 2020 and running into 2024.

Distributed Generation

Afanasiev said the company sees “opportunities in distributed generation” thanks to the rise of renewables. He said serving that market will be part of Siemens’ focus as it continues to upgrade its HL-class gas turbines, building on the “history” of its H-class turbines, including its SGT-8000H model technology. The HL class, including the SGT5-9000HL, SGT6-9000HL, and SGT5-8000HL models, has a mid-term goal of 65% generation efficiency.

Siemens has said that in simple-cycle operation the air-cooled SGT-9000HL gas turbine will provide generation capacity of 545 MW for the 50-Hertz market, mainly Europe and China, and 374 MW in the 60-Hertz set-up, used in the U.S., Japan, and the Middle East. The SGT5-8000HL will provide 453 MW in simple-cycle operation.

GE Power’s Corron, discussing upgrades in the company’s 7HA.02 gas turbine, said one improvement in the model is the use of titanium to make the unit lighter and stronger, as compared to the 7HA.01 model. He said GE is “leveraging insight from our aviation experience for power generation.”

GE’s air-cooled HA turbines are a step up from the company’s earlier, steam-cooled H-class turbine. The new HA turbines, which include 9HA.01 and 9HA.02 models, were designed for simplicity and easy serviceability. The company has spent more than $2 billion on development and launch of the HA class, which included $200 million for a full-scale test plant in Greenville, South Carolina.

Darrell Proctor is a POWER associate editor (@DarrellProctor1, @POWERmagazine)