Siemens Energy will devote the next four years to testing one of the world’s largest natural gas turbines at Duke Energy’s Lincoln Combustion Turbine Station in North Carolina. That’s just a fraction of time in the life cycle of the new turbine.
By Jean-Cosme Delaloye
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Kevin Murray, a Vice-President of Project Management and Construction at Duke Energy, and his project team are working with Siemens Energy to ensure the turbine generates the energy needed to ultimately serve more than 300,000 homes. “When investing in a new generating asset, we consider performance, efficiency and costs over the entire 30-year-plus life cycle of the unit,” says Murray, who has worked in the power industry for more than 25 years.
Nestled on 60 acres at the Lincoln site, the new turbine stands out among the 16 other natural gas turbines. “It is a monster,” Murray says. “Its size and scale definitely make it stand out.” Siemens Energy approached Duke Energy in 2017 to build the first SGT6-9000HL gas turbine generator at a factory in Duke Energy’s service territory and then test it in real-life conditions connected to the grid during a four-year process that started in 2020 and will end in 2024.
“When we look at a new generating asset, we consider performance, efficiency and maintenance cost over the entire life cycle, so we look out 30 years.”Kevin Murray, Duke Energy’s Vice-President for Project Management and Construction
Turning the unit into a “porcupine” to collect data
The team fired up the unit’s engine for the first time in April 2020, confirming the engine and the auxiliary systems – including natural gas supply and the lube oil, control and start-up systems – are working together as designed. “First fire and initial synchronization of a new gas turbine are very powerful moments,” Murray says. “These milestones represent the culmination of a tremendous effort by design, manufacturing, construction and operational teams.” The four-year testing process started in May – all during the coronavirus pandemic.
During testing, Duke Energy customers receive the unit’s energy while paying only some fuel costs, while Siemens Energy introduces variations of the turbine and continually improves technologies. “We plan to test multiple combustion configurations, including the advanced combustion for the efficiency system,” says Diego Caso, Siemens Energy’s Testing and Validation Director. “This system requires less cooling air through the combustion system, which reduces the turbine inlet temperature while maintaining a high power output and low emissions.”
A validated turbine has 200–300 standard instruments, but Caso’s testing and validation team turned the four-stage, 340-ton turbine into a giant “porcupine,” says Malcolm Moore, Siemens Energy’s Lincoln Site Manager. “The unit has the standard instruments and more than 6,000 additional probes with cables running from each probe to our data monitoring systems.”
Engineers and instrumentation mechanics closely monitor signals from eleven different cabinets with thousands of wires feeding data boxes. They will use this data to achieve the next level of efficiency and address the needs of energy markets around the globe.
Using the turbine to support solar generation
In 2024, Siemens Energy will turn the unit over to Duke Energy. It will be Duke Energy’s most efficient simple-cycle combustion turbine in the fleet and 34% more efficient than the other turbines at the Lincoln site.
The new unit will also play a part in the company’s strategy to cut carbon dioxide emissions by 50% by 2030, help Duke Energy continue to close older, less efficient coal-fired units and support the company’s growing portfolio of solar generation. “North Carolina is ranked No. 2 in the USA for installed solar,” Murray says. “When the sun stops shining, we see big swings in our load, and operators can quickly start this unit to compensate for that – maintaining the reliability of our grid.” The turbine’s ramp-up rate is 85 megawatts a minute in comparison to other technologies that have ramp- up rates of 10–20 megawatts a minute.
Nearing the finish line
Testing under way at the Lincoln site is the final step in Siemens Energy’s three-step testing and validation process for the SGT6-9000HL. Engineers already tested the unit’s components and prototype last year in Berlin, Germany. Siemens Energy is also testing a 50-hertz version of the engine in a combined cycle SGT5-9000HL power plant at Keadby 2 in the United Kingdom.
“A lot of the testing of the 60-hertz engine at the Lincoln site is directly applicable to the 50-hertz engine because they are perfectly scaled,” Caso says. Though the road to 2024 is long, the sense of achievement is palpable, especially given the success of the initial testing phase.
“It took us five years from the conceptual design to manufacturing and assembly to push a button and see this baby take its first breath,” says Thomas Koeppe, a Siemens Energy Engineering Manager who has been involved in the turbine’s design since its inception in 2015. “The Lincoln site provides a learning opportunity that gives us confidence in how this product is designed and works.”
Jean-Cosme Delaloye is a New York-based reporter and award-winning filmmaker, working for various European media outlets such as Tribune de Genève, 24 Heures and Swiss national television
Combined picture credits: Siemens Energy, Duke Energy
Facts and figures
- First fire: April 2020
- Weight: 340 tons
- Frequency: 50 Hz & 60 Hz
- Simple-cycle output: 405 MW
- Fuel: Natural gas, LNG, distillate oil
- Combined cycle efficiency: > 63%
- Fuel can contain up to 30% hydrogen
- Ramp-up rate: 85 MW/min
- Turbine speed: 3,600 rpm
- Four-stage turbine
- Gross efficiency: 42.6%
- NOX emissions: Down to 2 parts per million by volume, dry (ppmvd) with Selective Catalytic Reduction (SCR), or ≤ 25 ppmvd (without SCR)
- CO emissions: 10 ppmvd
- Advanced can-annular combustion system with dual fuel capability allows for higher firing temperatures and more operational flexibility