July marks two important milestones that set gas-fired generation on its course to becoming a dominant form of power generation: commercial operation of the world’s first industrial gas turbine in Neuchâtel, Switzerland, in 1939, and commercial operation of the first gas turbine in the U.S. used to generate electric power—a 3.5-MW General Electric (GE) unit at the Belle Isle Station in Oklahoma City in 1949.

GE, which today is the largest original equipment manufacturer in the gas turbine space, has since developed and deployed several generations of gas and steam turbines, generators, heat recovery steam generators (HRSGs), condensers, and other balance-of-plant equipment. Here is how GE’s modern gas turbine model portfolio has evolved over the past 80 years.

1953 First Commercial Intercooled Recuperated Gas Turbine with Reheat

Technology breakthroughs in cycle pressure ratio, materials, and coatings that follow the Neuchâtel unit enable BBC to boost turbine inlet temperatures to 1,200F, and in 1953, the company starts up the 27-MW Beznau II plant, boosting thermal efficiency of the two-unit 40-MW Beznau power plant in Switzerland to 30%. BBC engineers of the two-shaft Beznau turbine squeezed “every bit of efficiency from the Brayton cycle with limited cycle pressure ratios and cycle maximum temperatures,” wrote S. Can Gülen in his February 2019-released book Gas Turbines for Electric Power Generation. “The end result was a whole power plant instead of a compact engine in a skid.”

1960 First Commercial CCGT

Encouraged by new gas discoveries in the Netherlands, NEWAG, an Austrian utility, puts into service Korneuburg-A, a 75-MW combined cycle plant—one of the first of its type to be built in Europe. The plant consists of two 25-MW BBC Type 12 turbines, a 25-MW steam turbine, and a HRSG with supplementary firing. Despite its low efficiency (of about 32.5%), the unit operates at baseload from 1960 to 1975, with an average of 6,000 hours per year, but it soon becomes uneconomical to operate, mainly owing to fuel costs and better efficiencies at coal plants, which came online in Europe from 1965 onward, and is thereafter used mostly for peaking duty.

1967 First Dedicated GE Combined Cycle Plants

In the aftermath of the Great Northeast Blackout of November 1965, regulatory mandates force utilities to increase system reserve margins by installing a certain percentage of smaller, localized, fast-start generating units with black-start capabilities. GE installs an 11-MW FS3 in the City of Ottawa, Ontario, and a 21-MW FS5 at Wolverine Electric Ottawa, also in Ontario. The FS3 had already been tested in U.S. maritime vessels and in locomotives, noted Ronald Hunt, a consulting engineer who is part of the Institution of Diesel and Gas Turbine Engineers (IDGTE), in his April 2019-released book The Development and History of the Gas Turbine for Power Generation, Industrial, and Marine Purposes.

1968 First LM Turbine

GE engineers reconfigured the J79 turbojet, an aircraft machine that was first flown in 1955, as the LM1500, a turbine with industrial and marine uses. The first LM1500 is a 13.3-MW turbine installed at the Millstone nuclear plant in Connecticut.

1969 More Sophisticated Aeroderivatives

The first LM2500, derived from the CF6-6 flight engine, powers the U.S. Navy’s GTS Adm. Callaghan cargo ship. The turbine uses a 16-stage compressor section with inlet guide vanes and 6-stages of variable stator vanes, with a two-stage high-pressure turbine section exhausting into a 6-stage free power turbine. The original design had twin-shaft HPT blades and an ISO power rating of 17.9 MW and a 35.8% simple cycle thermal efficiency. LM2500 turbines are still widely in use today. “To this day, the U.S. Navy continues to select the LM2500 to power the latest surface combatants in its fleet,” GE says.

1970 Frame 5 Gets Bigger

Sales of the Frame 5, a single- and twin-shaft, simple cycle, axial-flow turbine, remain brisk. In 1970, an aluminum smelter in Bahrain employs a Frame 5 unit with 24-MW rating. The model has today acquired a venerable status in the gas turbine world because of its reputation as a reliability workhorse. As Dave Lucier, who managed GE’s field engineering program, noted some years ago, a black-start Frame 5 in Southampton, New York, initiated the restoration of power on Long Island, and eventually New York City, following the Great Northeast Blackout on Nov. 9, 1965. “The future is nothing without the past,” he remarked.

1970 Frame 7 Appears

The MS7000, a Frame 7 (60 Hz) turbine, appears, rated at 47.2 MW with a TIT of 1,650F. GE soon after begins developing the 50-Hz Frame 9 single-shaft machine with Alstom.

1970 BBC Launches the GT Series

To compete for market share in the upturn for gas turbines in the aftermath of the blackout, and responding to GE’s strategy to build larger gas turbine units, BBC develops the GT11 (60 Hz) and GT13 (50 Hz) families. BBC’s first GT11 gas turbine is ignited at Rainbow Lake in Canada in 1970. It is rated at 32 MW at 3,600 rpm.

1971 First E-Class Turbine

The first E-class (a 7E) is debuted at National Grid’s Shoreham Combustion Turbine plant in the UK.

1972 First 7B

GE introduces the MS7001B, the first Frame 7 B-class turbine, rated at 51.8 MW.

1975 First Frame 9

The first 80.7-MW Frame 9B machine is installed by EDF near Paris, for mainly peaking duty.

1978 First 6B

The first 6B machine is installed at Montana-Dakota Utilities’ Glendive station. The turbine is still in operation, said GE Gas Power CEO Scott Strazik in September 2018. Another 1,150 6B turbines are installed across the world, powering energy production facilities and industrial applications in segments such as petrochemical, oil and gas exploration, and cement production, GE noted. Over the years, the company has improved the technology. In 1981, it developed technology to increase firing temperatures, leading to 15% more output. In 1991, it introduced dry low-NOx combustion technology, and in 2009 it introduced a performance improvement package featuring advances in materials, coatings, sealing, and aerodynamics derived from its F-Class line. To mark the 40th anniversary of the installment, GE in 2018 also unveiled a 6B fleet repowering solution as part of an effort to continue investing in its “mature fleets” to keep them competitive.

1984 Dry Low-NOx Breakthrough

The first commercial operation of first-generation BBC-developed “lean” dry low-NOx (DLN) premix combustion begins at a modified GT13D unit at the 420-MW combined cycle Lausward plant in Dusseldorf, Germany. As Dietrich Eckardt notes in his 2014-published book Gas Turbine Powerhouse, BBC presented the concept in 1978 based on theoretical insight that effective low-NOx combustion required the separation of fuel/air mixing from the combustion process and that combustion itself should take place under “lean” conditions. The technology lowered the unit’s NOx emissions to 32 parts per million (ppm). Although it was later applied to seven GT units, it was “too complex and prone to deterioration after a while,” which is why BBC began development of a second generation of lean premix burners, said Eckardt.

1985 Cogeneration Milestone

Two GE LM2500 aeroderivative gas turbines, a steam turbine, and a generator mounted in a single-shaft configuration are installed at a district heating system owned by IJsselcentrale in the Netherlands. The configuration is designed to offset the high investment cost of the LM2500 gas turbines. GE notes the project also marked its first steam injection system application. Performance tests show a full-load efficiency of 50%.

1987 First GT13E Launched

The first ABB (later Alstom, and then GE) GT13E—a 147.9-MW unit—is successfully commissioned at the Hemweg facility, owned and operated by Dutch utility UNA, in the Netherlands. Another 27 units of this type were put into operation before market demands push the company to develop gas turbines with higher efficiencies and NOx emissions below 25 ppm. In 1991, it launches the GT13E2. The turbine uses a single, top-mounted SILO combustor.

1988 LM6000 Launched

GE expands the LM fleet to include the LM6000, a turbine that is derived from GE’s CF6-80C2 high bypass turbofan aircraft engine. The simple cycle, two-shaft, high-performance gas turbine has a capacity of up to 36.6 MW and an efficiency of 41.9% at the ISO rating point.

1990 The F-Class Era Begins

The first F-class machine, a 147-MW 7F with a TIT of 2,300F, began operating at Virginia Electric & Power Co.’s (VEPCO) Chesterfield Power Station on June 6, 1990. While the prototype was initially used for simple cycle testing before it was converted to combined cycle in 1992, sources widely report that it had an efficiency of 45.2% and a total power output of 214 MW in combined cycle mode (and 150 MW and 34.5% in simple cycle mode). According to the 7F Users Group, Chesterfield 7 marked the beginning of the golden era for gas turbine technology (which ended in 2015, according to some industry observers). The group alsopoints out that F-class machines have grown “in complexity over the years to satisfy ever more demanding environmental regulations and owners’ goals of higher efficiency and availability/reliability.”

GE notes F technology was initially designed in the 1980s, when it represented “a quantum leap in the operating temperatures, cooling technology and aerothermal performance of heavy-duty gas turbines.” Since GE introduced the the MS7001F in 1987, a design driven “by the demand for higher efficiency plants with lower emissions and lower cost (per kW/hour),” the technology has been scaled upward and downward, and it is today available in outputs ranging from 51 MW for a 6F.01 simple cycle plant to more than 1,000 MW for a 3×1 7F.05-based combined cycle plant. The family has expanded to 6Fs and 9Fs. More than 1,500 F-class machines have been installed worldwide, with applications that range from power generation, combined heat and power, and mechanical drive applications, in industries as diverse as aluminum smelting, refineries, and food processing.

1991 Commercial Dry Low NOx Solution

While GE began developing and testing dry low-NOx (DLN) combustion systems in the 1970s, it introduces its first commercial DLN combustion systems for gas and heavy-duty gas turbines in 1991. Research efforts yield the DLN-1 solution for E-class turbines, and the DLN-2 solution for F-class turbines; the latter has also been applied to EC and H-class machines. In 2015, GE introduced a DLN2.6+ combustion system for new and existing 7F gas turbines, and in May 2018 it announced a “flex” upgrade solution, which combines the DLN 2.6+ combustor with axial-fuel-staging technology. Earlier this year, the company said it completed the first installation of a new gas-fired power plant technology that can reduce NOx to 5 ppm.

1992  The First 9F

A 159-MW 7F with a 2,350F TIT begins operating at another Chesterfield unit (Chesterfield 8) in Virginia, and the first 9F begins operating in simple cycle mode at an EDF site in northern Paris. GE jointly developed the 212-MW turbine with Alstom.

1992 The GT13E2

ABB introduces the 166-MW GT13E2 gas turbine to the market. Compared to the GT13E, the GT13E2 has a higher TIT of 2,012F and increases the compressor ratio from 13.9:1 to 15.0:1. GE still offers the turbine model today. The GT13E2 2017 delivers 210 MW with 38% simple cycle efficiency and more than 55% combined cycle efficiency, it says.

1996 Power Plant on Wheels

GE unveils the TM2500, a trailer-mounted portable aeroderivative—a “power plant on wheels.”

1997 F-Class Competition Yields the GT24/GT26

GE’s introduction of the 150-MW Frame 7F—the first F-class model—in 1987 was quickly followed by Westinghouse (in collaboration with Mitsubishi) in 1989 with the 501F, and then in 1991 by Siemens with its V94.3. That’s why, Eckardt notes, ABB “decided for a ‘leap frog’ strategy to position itself to catch up with its competitors.” The company launched its own GT24 (60 Hz)/GT26 (50 Hz) in December 1991. A 165-MW GT24 prototype was installed at the Gilbert power plant in New Jersey in 1993. “Presented as a revolutionary solution, it was the most compact model available on the market and the only one to use sequential combustion with a particularly high compression ratio,” he notes. It also had an efficiency of 56%, which was 2% to 3% more than its competitors. The GT26 was launched in 1997. The 770-MW Rocksavage gas-fired power station in the UK is one of the first to be equipped with GT26 gas turbines.

2003 The H-Class Era Begins

GE unveils the first H-class system (H-System), 9H, a 50-Hz 480-MW turbine, with firing temperatures of 2,600F, at Baglan Bay Power Station in Wales. The 9H—a single-shaft combined cycle plant—achieves a firing temperature well above 2,600F. But as Gulen notes in his February 2019 book, while the H-System “was an unqualified success from a technology perspective, it was a commercial failure.” Single-crystal, hot-gas-path components with advanced thermal barrier coatings added to the cost and complexity with longer-than-typical major maintenance outages, he notes. Altogether, only six H-System combined cycle power plants were built and continue to operate commercially, and while one of those plants—the 60-Hz Inland Empire Energy Center—has achieved notable heat rate and NOx emissions parameters, GE does not offer the H-System anymore. The newest stars of its H-class lineup are its HA models.

GE’s launch of the H-System, however, heated up competition among major manufacturers in the large gas turbine space, who doubled down on efforts to boost gas turbine efficiency. In 2011, Siemens broke the 60% thermal efficiency barrier with its 8000H gas turbine in Irsching, Germany, a gas turbine that nominally had the same TIT as the H-System (2,732F), but a lower firing temperature. Westinghouse, meanwhile, pursued the intermediate G-class firing temperature in collaboration with Mitsubishi Heavy Industries (MHI)—technology that is now offered by Mitsubishi Hitachi Power Systems (MHPS). MHI also dropped development of H technology and began development of the J-class, whose combustor technology is based on the steam cooling system used in the G-class.

2005 The 6C Takes Root

A 130-MW 2x Frame 6C (6F.01) CCGT is debuted in Turkey. The 6C, which is now known as the 6F.01, was originally introduced in 2003 at 42 MW and upgraded to 46 MW after site validation. GE says this model leads the industry for cogeneration and combined cycle efficiency for gas turbines with an output range of less than 100 MW. “Its tremendous exhaust energy allows the production of a high quantity of steam for either power generation or cogeneration. It achieves over 58 percent efficiency in 2×1 combined-cycle arrangement, and more than 80 percent efficiency in cogeneration operation,” it says.

2009 Alstom’s MXL2 Upgrade

Alstom rolls out its GT26 MXL2 advanced gas turbine upgrade at Castejon power plant in Spain. The MXL upgrade allows GT26 owners to benefit from new optimizations to the compressor, and coating and cooling improvements in the HP and LP turbines. It also extends the life of equipment. While the MXL concept began as a standard feature of the newer GT13E2 fleet, Alstom also installed the first MXL2 upgrade for its GT13E2 gas turbine at the South Humber Bank Power Station in the UK in 2012.

GE today offers the MXL2 upgrade in its GT13E2 turbines, which it acquired from Alstom in 2015. As part of the Alstom acquisition, however, GE agreed with the European Commission to divest a part of Alstom’s gas turbine portfolio to preserve competitiveness. The divestment included, in general, Alstom’s GT26 and and J-class GT36 gas turbine technology and some of the GT26 services contracts, all which were sold to Ansaldo Energia. Nevertheless, GE retained all GT24 services contracts. Ansaldo today offers the MXL2 upgrade for the GT26, and GE packaged the upgrade in a new offering, the GT26 HE, which it rolled out in 2019. Ansaldo today offers the MXL2 upgrade for the GT26, and GE packaged the upgrade in a new offering, the GT26 HE, which it rolled out in 2019.

2014 GE Launches the HA Line

Marking a major new milestone, GE introduces two new air-cooled H-class turbines, the 9HA (50-Hz) and 7HA (60-Hz), which are developed through advancements in materials, aerodynamics, and advanced manufacturing. The turbines also incorporate the benefits of the new digital era where integrated software and analytics drive greater performance and efficiency. GE says the turbines, which range from 290 MW (7HA.01) to 571 MW (9HA.02), will break records for efficiency.

2015 GE Acquires Alstom’s Power Business

Following regulatory approval of a $10.6 billion transaction in more than 20 countries and regions, GE’s acquisition of Alstom’s energy activities is completed in November 2015.

The deal is GE’s biggest transaction ever. Jeff Immelt, who was then GE’s CEO, said GE’s acquisition of Alstom’s complementary technology, global capability, installed base, and talent meant immediate benefits for customers, including for current projects using GE 7HA gas turbines and Alstom’s HRSGs and steam turbines. It is also a boon for a number of proposed projects. In November 2017, however, another former GE CEO, John Flannery, revealed that Alstom had “clearly performed below our expectations.” GE bought the French company for four reasons: its installed base; a broad product line in steam and power islands, which GE anticipated it could cross-sell; synergies across operations, costs, and revenues; and the talent of Alstom’s personnel, which ultimately paid off. But GE was hurt by a “market clearly dramatically lower than what we underwrote in that business,” Flannery said.

2016 First HA Deployed

The first 397-MW 9HA.01, with an efficiency of 62.22%, deploys at EDF’s Bouchain plant in France. The project is a POWER Top Plant in 2017 .

2017 LM9000 Launched

As market demand for aeroderivatives picks up to help balance the growing shares of renewables, GE introduces the LM9000, a 67-MW to 75-MW power plant derived from the GE-90 aircraft engine, which is fitted on a Boeing 777.

2017 6F.01 Relaunch for Distributed Market

To gain some clout in the surging distributed energy market, GE relaunches the 6F.01 turbine, outfitting it with advanced materials and technologies adopted from GE’s H- and F-class gas turbines. The relaunched model is first installed at the Huaneng Guilin Gas Distributed Energy Project. The 50-MW 6F.01 at that project boasts a combined cycle efficiency of 57% and fuel utilization rate of 81.15%.

2017 7HA.02 Milestone

Exelon’s Wolf Hollow and Colorado Bend projects in Texas debut the 7HA.02 turbine. Both plants are configured as 2×1 multi-shaft with total plant output greater than 1,000 MW at each site.

2017 First 7HA.01

GE and Toshiba collaborate to install six 7HA.01 gas turbines and two steam turbines at Chubu Electric Co.’s Nishi Nagoya thermal power plant in Aichi Prefecture, Japan. The first block of three units reached commercial operation in September 2017. Block 1 has achieved a gross combined cycle efficiency level of 63.08%, which sets another world record for highest gross efficiency. The second block of three units reached commercial operation at the end of March 2018. The project was a POWER Top Plant in 2018 .

2018 Dual-Fuel HA

In June 2018, PSEG Power, a subsidiary of PSEG, begins commercial operation of its Sewaren 7 combined cycle power plant in New Jersey. The 540-MW unit, a 7HA.02, is the first dual-fuel H-class turbine in the world. The plant is designed to operate on two types of fuel, including natural gas and ultra-low-sulphur distillate (ULSD) fuel oil. The dual-fuel capability enables the use of ULSD in the event of a shortfall in natural gas supply, increasing the plant’s dependability and reliability.

2019 First 9HA.02

GE’s largest HA turbine to date—the 571-MW 9HA.02—is shipped to Southern Power Generation Sdn Bhd (SPG) for its new Track 4A plant, a 1,440-MW combined cycle power plant in Pasir Gudang, Johor, Malaysia. It will consist of two generating blocks, each equipped with a 9HA.02 gas turbine, generator, and HRSG from GE.

2019 GT26 HE Launched

GE introduces the GT26 High Efficiency (HE) upgrade, blending GE and Alstom technology, to cater to high renewables penetration. Uniper will install the turbine at the Enfield Power Station in the UK in 2020. “If you think of upgrades that we’ve done in the past, they’ve been what I would say, piecemeal, either a hot-gas-path AGP [advanced gas path] that you may be aware of, a combustor, or a compressor. With the HE—the high-efficiency upgrade—we are actually hitting every module. We’re looking at the LP [low-pressure] turbine, the compressor, and the combustor,” Amit Kulkarni, general manager for the F/H-class product line organization within GE Power Service, told POWER in March. “So, it’s the most-advanced upgrade for this model, and it blends technologies from both F as well as our HA class units. It also combines technology and expertise with both GE and Alstom.”

—Sonal Patel is a POWER associate editor. (@POWERmagazine, @sonalcpatel)