First Gas Turbine Upgrade Blending GE and Alstom Technology Unveiled

GE introduced its GT26 HE (high efficiency) gas turbine upgrade on March 25 by announcing Uniper would be the first to install the new technology at the company’s Enfield Power Station in London, England.

“We’re proud to launch our new GT26 HE upgrade with Uniper—it’s the most advanced solution we’ve ever introduced on a GT26 gas turbine, and one of our most efficient upgrades within the F-class portfolio,” Scott Strazik, president and CEO of GE’s Gas Power business, said in a press release. “Not only will this upgrade revitalize Uniper’s Enfield power plant, it will also improve its competitive position in the Great Britain generation market, supporting its long-term profitability and viability.”

First Blending of GE and Alstom Technology

The GT26 HE upgrade is also the first such improvement to blend both GE and Alstom technology and expertise across all major components of a gas turbine solution. The upgrade is said to take the best technologies and capabilities from GE’s industry-leading F and H-class fleets to create a robust solution for GT26 power plant operators.

“If I look at the F-class, we have around 1,400 gas turbines installed—7F, 9F, GT24, GT26. The GT26 was manufactured by Alstom and it came into the GE family in 2015 after we acquired Alstom. It’s around 90 units that sit in Europe, Middle East, Asia,” Amit Kulkarni, general manager for the F/H-class product line organization within GE Power Services, said during an exclusive interview with POWER.

“I’ve been in this role for a few years and I get the question all the time: ‘Does GE care about the legacy Alstom GT26 fleet?’—90 units versus 7F, which is 900. And I’ve always answered that: ‘Yeah, we do care, because every unit that we service is critical to us,’ ” Kulkarni said. “This is one of our largest investments in this fleet,” he added.

“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. 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. As you know, both businesses have been in the gas turbine industry for decades, and this is an example of combining that into creating this upgrade.”

The upgrade will be installed at Enfield in the second half of 2020. The outage is expected to take 120 days including validation, which involves a lot of sensors and data collection as part of the performance testing. Future upgrade outages are expected to be completed within a 60-day window.

“The technology that has come into play here are several-fold. If I look from a turbine standpoint, we’re actually leveraging a lot of the work we’ve done in GE’s H-class machines. We’re leveraging improvements on cooling, on coating, that came along when we developed the H class to drive the higher firing temperature that you need. So, that’s one big feature of the LP turbine,” Kulkarni said.

Additive manufacturing, or 3-D printing, was also said to be vitally important to the improvement. According to GT26 Product Manager Simone Serges, it’s really the first time additive manufacturing has played a significant role in an F-class unit. “And it’s not just for the sake of introducing 3-D-printed parts in an upgrade. It’s really an enabler that allows us to achieve this huge efficiency step, because on one side we are able to push higher the firing temperature, as [Kulkarni] said, which with the standard manufacturing techniques this wouldn’t have been possible, but also it allows us to optimize the cooling consumption, and therefore again, improve the efficiency. So, it’s really a double use of this technology—this manufacturing technology,” Serges told POWER.

Of course, GE has experienced some “teething issues” with its HA gas turbine. Kulkarni said he doesn’t expect those to carry over into the GT26 for a number reasons. “The HA is a lot more complex and a much higher firing temperature gas turbine than anything else on the planet, reaching 63% efficiency. Some of those issues that we’ve talked about on the stage-one blades oxidation issue are not going to manifest here with the GT26 because inherently different material and different heat treatment as we’ve seen to be really the root cause. It’s not even the materials, it’s really the heat treatment and the process that we’re using that we had to go change to develop the new solution [for the HA gas turbine]. Here [on the GT26] that is not going to be the issue.”

Higher Efficiency and Increased Output

The key performance benefits the GT26 HE upgrade is expected to deliver include:

  • Increasing combined cycle plant baseload efficiency by more than 2%, which translates to as much as $4 million in fuel savings annually per unit.
  • Increasing the efficiency by up to 1% in part-load operation, yielding up to $1 million in fuel savings a year per unit.
  • Increasing plant output from 15 MW to 55 MW per unit depending on the vintage of the original gas turbine, which improves revenue opportunities.
  • Extending inspection intervals up to 32,000 hours from the typical 24,000-hour recommendation, reducing long-term maintenance costs.

“We’re very pleased to be working with GE on this new technology upgrade,” Eckhardt Rümmler, chief operating officer with Uniper SE, said in a press release. “In Great Britain’s very competitive and challenging power generation environment, investing to keep our plants competitive by lowering operational and maintenance costs at the same time as increasing efficiency and flexibility is critical for the long-term success of our fleet.”

“If I look at Uniper with the 20 years of operation that they have at Enfield, this allows them to probably go another 15 years of service and be profitable. The improvement in efficiency is significant with the upgrade that allows them to dispatch the unit even more—even go beyond the current number of hours they run the machine—and it’s a win-win from that perspective,” Kulkarni said.

Aaron Larson is POWER’s executive editor (@AaronL_Power, @POWERmagazine).