Baglan Bay Power Station, Cardiff, Wales, UK

June 16, 2008 at 12:51 am | Posted in Power Plant | 2 Comments

Developed by GE Power Systems

Operated by GE Europe Operations & Maintenance

GE’s H System is the first gas turbine combined-cycle system capable of breaking the 60% fuel efficiency barrier. Why is that so important? Fuel is the single largest cost of running a power plant, and even a 1% gain in thermal efficiency can mean as much as a $15 million to $20 million saving over the life of a typical plant of this size. The H System’s increased firing temperatures result from using steam from the bottoming cycle to cool the hot gas path parts without relying on film cooling.

The world’s largest and most powerful single-shaft, combined-cycle system has made its global debut (Figure 1). It produced commercial power during a recently completed testing program at the Baglan Bay Power Station in Cardiff, Wales, UK.

1. World’s largest.

Baglan Bay is home to the world’s first installation of General Electric’s newest gas turbine technology, the H System. The world’s largest and most powerful single-shaft, combined-cycle system produced commercial power during a recently completed testing program.

Courtesy: General Electric Power Systems

The new facility features the world’s first installation of GE’s next-generation, gas turbine combined-cycle technology, the H System. This technology is designed to achieve 60% thermal efficiency when operating on natural gas. That is a major milestone for the global power industry; the most efficient systems today operate in the 57% to 58% efficiency range.

During the recently completed testing period, the H System at Baglan Bay generated up to 530 MW at 44F for the UK national grid. The H System was introduced at a rating of 480 MW operating on natural gas at ISO conditions. Following a planned outage to change out the instrumented components, the H System will be restarted for a commercial demonstration period beginning in September (also see the interview with John Rice, president and CEO of GE Power Systems, on page 36).

Built by GE on land leased from BP, the Baglan Bay Power Station also features a 33-MW combined heat and power (CHP) plant based on a GE LM2500 gas turbine (Figure 2). The power complex will provide electricity and steam to the adjacent Baglan Energy Park and BP Chemical’s isopropanol plant, with the remaining electricity supplied to the national grid. The power station is being operated by GE’s European Operations & Maintenance group.

2. H System at work.

During the recently completed testing period, the H System at Baglan Bay generated up to 530 MW at 44F for the UK national grid. The H System was introduced at a rating of 480 MW operating on natural gas at ISO conditions. Built by GE on land leased from BP, the Baglan Bay Power Station also features a 33-MW combined heat and power plant based on a GE LM2500 gas turbine.

Courtesy: General Electric Power Systems

Advanced turbine development

Introduced in 1995, the H System was developed by GE as part of the U.S. Department of Energy’s Advanced Turbine System program. GE has designed and built two H technology gas turbines: the 50-Hz 9H (the model installed at Baglan Bay) and the 60-Hz 7H. The 9H (Figure 3) is believed to be the largest gas turbine in the world; it is 39 feet long, 16 feet in diameter, and weighs 811,000 pounds.

3. The Frame 9H gas turbine on its way to Baglan Bay.

The 9H is believed to be the largest gas turbine in the world; it is 39 feet long, 16 feet in diameter, and weighs 811,000 pounds.

Courtesy: General Electric Power Systems

Both H turbine models derive their performance from advanced materials and a new steam cooling system that allows operation at a 2,600F firing temperatures, 200F above previous-generation F technology machines. This higher firing temperature is the key to the H System’s higher efficiency (see table).

MS7001H/MS9001H performance

Source: General Electric Power Systems

GE’s development team based much of the H System’s design on proven turbine technology. The H compressors were based on the compressor designed for the CF6-80C2 aircraft engine and its aeroderivative LM6000 gas turbine. The 9H compressor has a 23:1 pressure ratio and an airflow of 1,510 lb/sec.

A dry, low-NOx (DLN) combustion system premixes fuel and air prior to ignition, reducing emissions of the gas to 25 ppm for the 9H. This DLN system has been proven in millions of hours of operation in other GE turbines around the world.

Steam cooling advances

The H system’s closed-circuit steam cooling system, however, is a departure from traditional gas turbine airfoil cooling concepts. The H System uses steam from the intermediate-pressure (IP) superheater and the high-pressure (HP) steam turbine exhaust to cool the first- and second-stage nozzles and buckets. Typically, gas turbines use compressor air to cool the turbine nozzles and buckets in an open-loop design. Closed-loop steam cooling reduces the temperature drop across the cooled part, allowing more energy to be efficiently used to generate electricity. Also, more air is available to expand and produce work through the turbine stages.

The most critical element of an advanced gas turbine is its hot gas path. The compressor discharge air and fuel are mixed and burned in a chamber at a specific condition—combustion temperature. The flow stream of high-pressure, high-temperature combustion products is accelerated as it passes through the first stationary airfoil (stage 1 nozzle segment). The firing temperature—the flow stream temperature at the inlet to the first rotational state (stage 1 bucket)—establishes the power output and, ultimately, the cycle efficiency. The difference between firing temperature and combustion temperature is the temperature drop required to cool the stage 1 nozzle.

In F-class turbines, for example, the stage 1 nozzle is cooled with compressor discharge air flowing through the airfoil and discharging out into the combustion gas stream as the airfoil is cooled. The cooling process causes a temperature drop of up to 280F across the stage 1 nozzle. If the nozzle could be cooled with a closed-loop coolant without film cooling, the temperature drop across the stage 1 nozzle would be less than 80F, which would permit a 200F rise in firing temperature with no increase in combustion temperature.

After passing through the H turbine nozzles and buckets and picking up thermal energy, the steam is returned to the reheater via the cold reheat line. Thus, the H turbine serves as a reheater for the bottoming cycle. The third-stage nozzles and buckets are air-cooled, and the fourth stage is uncooled.

The keys to achieving single-digit NOx emissions from the H system are the higher firing temperature and the closed-loop cooling of the stage 1 nozzle. The cooling concept has a dual effect, allowing higher firing temperatures to be achieved without combustion temperature increases and permitting more compressor discharge air to flow to the head-end of the combustor for fuel premixing.

In addition to developing steam cooling, the GE engineering team designed the H turbine’s first-stage buckets and nozzles with single-crystal materials to withstand higher temperatures over a long service life. A GE-proprietary, dense vertically cracked, thermal-barrier coating insulates the nozzle and bucket base metals from the hot combustion gas.

Another key feature of the H System is a significant increase in power density. Compared to F technology plants, the H System delivers about 45% more power per square foot.

Successful development testing

The H System was GE’s most thoroughly tested power generation technology in the company’s more than 100-year history. First, factory tests involving 100 engineers were conducted at three locations in the U.S., including GE’s Greenville, S.C., gas turbine plant. This testing phase encompassed materials, component, subsystem, and system testing of the compressor rigs, as well as tests of the combustion, inlet aero, and Mark VI control and integrated control systems . These tests were followed by two full-speed, no-load factory tests.

The first 9H gas turbine was shipped to Baglan Bay in December 2000, and a comprehensive series of field tests totaling nearly 300 hours and involving 150 engineers began in November 2002. These tests, which entailed placing more than 7,000 sensors on the equipment, validated GE’s innovative steam-cooled technology for the H System and successfully demonstrated the overall plant design. The extensive testing also has validated more than 100 critical-to-quality characteristics.

“During the test period, we had 26 successful fired starts of the gas turbine, with no failed attempts,” reports Brian Ray, GM of GE Power Systems’ Baglan Bay Asset Management Team. “The entire testing program went very smoothly, a remarkable achievement for a project of this scope. The keys to our success were the rigorous planning and implementation processes employed for the test program and the around-the-clock dedication and teamwork of the total project team. It was a global effort, involving more than 300 people from GE’s facilities in Greenville and Schenectady, as well as on-site personnel.”

“We’re very pleased with the results of the field tests,” echoes Mark Little, VP of GE Power Systems’ Energy Products group. “Our ongoing analysis of test data is correlating well with pretest engineering predictions.”

Inside Baglan Bay

At Baglan Bay, the H System’s 9H gas turbine, steam turbine, and generator are in a single-shaft configuration. The steam turbine is a D10 reheat, single-flow exhaust machine that was co-manufactured with Toshiba of Japan. Similar to other GE advanced single-shaft combined-cycle systems, solid couplings are employed to connect the gas turbine to the steam turbine, and the steam turbine to the generator.

4. Frame 9H rotor on the half shell in GE’s Greenville, S.C., facility prior to shipment to Baglan Bay.

The H compressors are derived from the CF6-80C2 aircraft engine. The 9H compressor has a 23:1 pressure ratio and a 1,510 pounds per second airflow.

Courtesy: General Electric Power Systems

The LM2500-based, CHP plant also includes a heat-recovery steam generator (HRSG), an auxiliary boiler, and a two-cell process cooling tower. The CHP plant will supply electricity, steam, and demineralized and attemperated water and provides the Baglan Bay complex with “black start” capability as well.

Other features of the Baglan Bay Power Station include:

  • A 660-MVA liquid-cooled generator.
  • The three-pressure-level HRSG.
  • A GE Mark VI integrated plant control system.
  • A 10-cell cooling tower.
  • A triple-flue, slip-form-poured chimney.
  • A service administration building with a GE Water Technologies treatment plant.
  • A 275-kV switchyard connecting to the UK’s national electricity grid.
  • A 33-kV switchyard with local supply to BP Chemicals and Baglan Energy Park.
  • A pipeline reception facility, for a 7-mile Baglan pipeline spur to the UK’s national gas transmission grid, with gas compression and pressure reduction capabilities.

Positive local impact

The Baglan Bay Power Station is located next to the Baglan Energy Park, a joint development involving BP, the Welsh Development Agency, and the Neath Port Talbot County Borough Council. Featuring business facilities for manufacturing, information technology, and call center firms, the energy park encompasses 2,500 acres and is one of the largest single areas of industrial development land in the UK.

Because of the proximity and high efficiency of the Baglan Bay Power Station, businesses locating in the energy park can potentially benefit from up to a 30% savings in electricity costs, helping to make them more competitive.

The new power plant replaces a 100-MW oil-fired facility at the Baglan Bay site. It will produce five times more power than the existing plant while burning natural gas, one of the cleanest fossil fuels available.

Construction of the power station, which began in October 2000, has contributed significantly to the local economy. Approximately 660 mechanical and electrical construction jobs were filled with local workers. An additional 640 local workers were engaged by the main civil contractor during the civil construction phase. Some 85% of the permanent operations and maintenance staff at the plant come from the immediate South Wales area.

In addition to direct employment, the power station has employed many local firms to provide goods and services required during the course of construction. Source Baglan, the initiative sponsored by Neath Port Talbot County Borough Council to maximize local content, estimates that more than 150 businesses have supported the project either directly or indirectly.

As a global showcase for power generation technology, the Baglan Bay Power Station is expected to offer a long-term benefit for the Port Talbot area by attracting engineers, scientists, and businessmen from around the world over the next several years.



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  1. The power output stated which is 480 MW is for the combined-cycle configuration. How about for the simple-cycle? Do you happen to know the output of the gas turbine itself (simple-cycle power output)?

    • The 9H can not be used in Simple-cycle. Steam is needed for cooling. This is convenient for the manufacturer, so they can mislead with power output of the product.

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