Gas Turbines News - Power Engineering https://www.power-eng.com/gas-turbines/ The Latest in Power Generation News Thu, 19 Dec 2024 17:13:10 +0000 en-US hourly 1 https://wordpress.org/?v=6.7.1 https://www.power-eng.com/wp-content/uploads/2021/03/cropped-CEPE-0103_512x512_PE-140x140.png Gas Turbines News - Power Engineering https://www.power-eng.com/gas-turbines/ 32 32 SWEPCO expands generation capacity with new gas, renewable resources https://www.power-eng.com/gas/swepco-expands-generation-capacity-with-new-gas-renewable-resources/ Thu, 19 Dec 2024 17:12:59 +0000 https://www.power-eng.com/?p=127424 Southwestern Electric Power Co. (SWEPCO) plans to add multiple natural gas-fired plants, along with new wind and solar farms, pending regulatory approval.

The American Electric Power (AEP) subsidiary has proposed adding a 450-Megawatt (MW) natural gas plant to be located at the previously retired H.W. Pirkey Power Plant site in Hallsville, Texas. The new Hallsville plant is expected to come online in 2027, pending approval from utility regulators in Arkansas, Louisiana and Texas. According to regulatory filings submitted December 17, the facility would feature two GE combustion gas turbine generators and utilize existing water intake structures and site infrastructure to minimize project costs, SWEPCO said.

The utility is also planning a coal-to-gas conversion project at the Welsh Power Plant, located northwest of Cason, Texas. The 1,053 MW project would convert the existing coal-fired boilers of Units 1 and 3 to burn natural gas, with Unit 1 conversion anticipated in 2028 and Unit 3 in 2027.

Natural gas currently accounts for 48% of SWEPCO’s existing power generation portfolio. Due to the evolving reserve requirements set by the Southwest Power Pool, SWEPCO anticipates an increasing capacity need.

In addition to the projects mentioned above, SWEPCO has selected a short-term capacity agreement with a natural gas-fired plant in Texas as part of a competitive bid process. The company said this agreement would serve as a bridge to more permanent resource additions.

SWEPCO continues construction on multiple renewable energy projects. The largest one, the 598 MW Wagon Wheel Wind Facility, spans five counties in Oklahoma and is expected to be operational in December 2025.

The 200 MW Diversion Wind Farm, located in Baylor County, Texas, is scheduled to begin operations this month.

SWEPCO’s first utility-scale solar farm, the 72.5 MW Rocking R Solar Facility, is also nearing completion in Caddo Parish, Louisiana. SWEPCO will not own the facility and will instead purchase the electricity generated via a purchase power agreement.

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SSE Thermal and Siemens Energy partner on hydrogen-ready gas turbines https://www.power-eng.com/gas-turbines/sse-thermal-and-siemens-energy-partner-on-hydrogen-ready-gas-turbines/ Mon, 16 Dec 2024 22:22:28 +0000 https://www.powerengineeringint.com/?p=148785 SSE Thermal and Siemens Energy have launched a collaboration to deliver gas turbine technology capable of running on 100% hydrogen.

The project is called Mission H2 Power, and will support the decarbonization of SSE’s Keadby 2 Power Station in North Lincolnshire, which is powered by Siemens Energy’s SGT5-9000HL gas turbine.

The multi-million-pound co-investment will see Siemens Energy develop a combustion system for its SGT5-9000HL gas turbine capable of operating on 100% hydrogen, while maintaining the flexibility to operate with natural gas and any blend of the two.

This will see additional facilities constructed at Siemens Energy’s Clean Energy Centre in Berlin to allow testing of the technology for large gas turbines to take place.

Finlay McCutcheon, managing director of SSE Thermal, commented in a statement: “We know hydrogen-fired power stations will be an essential element of the energy mix in a net zero world and Mission H2 Power will help us accelerate their deployment through engineering excellence.

“…Our projects will be pivotal in providing flexible backup to renewables and while we still need to see a rapid acceleration in policy and deployment, the need for this technology is beyond question – it is a matter of when not if and this partnership can help us reach that destination as soon as possible.”

Darren Davidson, vice president of Siemens Energy UK&I, added: “We are living in a transformative time for the energy sector. Our HL-class gas turbine has set records for efficiency and power performance. This new collaboration is a significant step in reaching the point where large gas turbines can run on 100% hydrogen.”

Investment in Mission H2 Power aligns with SSE’s commitment to transition away from the use of unabated fossil fuels in electricity generation and accelerate hydrogen projects.

SSE is also working on the Keadby Next Generation Power Station project in partnership with Equinor, to ensure the plant is capable of running on either hydrogen or natural gas, or a blend of the two. This allows for flexibility in the event of delays to the hydrogen infrastructure.

Delivering low-carbon power stations will be essential to providing a clean power system in the UK, with the plants fulfilling a vital role as flexible back-up in a renewables-led system. Analysis from National Energy System Operator shows that around 7GW of low-carbon flexible power will likely be needed on the system by 2035, with around half of that capacity provided by hydrogen-fired power stations.

Originally published in Power Engineering International.

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GE Vernova signs 9 GW of gas turbine reservations in past month https://www.power-eng.com/gas-turbines/ge-vernova-signs-9-gw-of-gas-turbine-reservations-in-past-month/ Fri, 13 Dec 2024 20:02:01 +0000 https://www.power-eng.com/?p=127299 GE Vernova has signed 9 GW of reservations for gas turbines with customers in the past 30 days, GE Vernova Chief Executive Officer Scott Strazik said in an interview with Bloomberg this week.

GE Vernova did not disclose any of the customers it had signed reservations for, but Strazik noted they include data center developers. Big tech names are moving to secure generation for their power-hungry campuses, with some facilities eying launch dates as early as 2028, Bloomberg reports.

GE Vernova has generated $4 billion in cash since its split from its parent company GE nine months ago. All of the new orders will be built out of the company’s South Carolina factory. The company expects to see 20 GW of gas turbine orders each year until 2028, with at least half of those orders coming from the U.S..

Order numbers from GE Vernova’s latest 10-Q in October (Credit: GE Vernova).

“We are very well positioned to serve this market,” Strazik told CNBC’s Jim Cramer this week. “We see it every day in both our grid and our gas businesses – a substantial increase in demand.” Strazik also told Cramer the company is poised to upgrade existing nuclear plants “this decade,” while SMRs aren’t expected to become a reality until roughly 2032.

While business is booming on the gas side, GE Vernova also laid out some troubling indicators for the already-struggling U.S. offshore wind industry. “The reality is, the economics of this industry don’t make sense,” Strazik told Bloomberg. The company said it is no longer seeking new sales for its offshore turbines in the U.S., and hasn’t sold one in nearly three years.

Certainly not helping the situation was the incident at Vineyard Wind offshore wind farm, in which a GE Vernova blade broke off of the installation, causing fiberglass and other debris to wash ashore for weeks on Massachusetts beaches. GE Vernova’s offshore wind turbine manufacturing plant in Quebec, Canada fired or suspended several workers in November following a probe into the incident.

In September, GE Vernova said it planned to cut up to 900 offshore wind jobs globally in a move to reduce its offshore wind footprint. The move came not only amid uncertainty and supply chain constraints in the offshore market but also another incident involving a GE Vernova Haliade-X turbine blade – this time at the Dogger Bank Wind Farm off the northeast coast of England. However, in this case, GE Vernova said its analysis showed that the blade event was not caused by an installation or manufacturing issue but instead occurred during the commissioning process, when the turbine was left in a fixed and static position, rendering it vulnerable during a subsequent storm with high winds.

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Choosing between Simple Cycle and Combined Cycle under new emissions standards https://www.power-eng.com/gas-turbines/choosing-between-simple-cycle-and-combined-cycle-under-new-emissions-standards/ Wed, 11 Dec 2024 17:43:39 +0000 https://www.power-eng.com/?p=127257 By Danny Bush, Associate Mechanical Engineer, Burns & McDonnell

By Joey Mashek, U.S. Sales and Strategy Director, Energy Group, Burns & McDonnell

The evolving regulatory landscape has presented power generation utilities with a complex choice as they consider large-scale gas generation projects and whether to build simple-cycle or combined-cycle power plants. With the U.S. Environmental Protection Agency’s (EPA) updated New Source Performance Standards (NSPS) for greenhouse gas (GHG) emissions, decision-makers must carefully balance operational efficiency, financial feasibility and output needs, while maintaining regulatory compliance. While results of the recent election and new administration may lead to some uncertainty with NSPS, the rule is currently still in effect.

The EPA’s NSPS aim to reduce greenhouse gas emissions from new and modified gas turbine power plants. Originally set at 1,000 pounds of carbon dioxide (CO2) per megawatt-hour (MWh), the standard under 40 Code of Federal Regulations (CFR) 60 Subpart TTTTa is now 800 pounds per MWh, with a further reduction to 100 pounds per MWh beginning January 2032.

These new standards significantly influence the decision between simple-cycle and combined-cycle plants, as they dictate whether plants can operate as baseload units or must operate at a lower imposed capacity factor if the above limits cannot be met. Adding further complexity, the updated standard introduces the concept of intermediate load facilities, with a required limit of 1,170 pounds per MWh and a capacity factor limit of 40%.

Combined-Cycle plants: High-efficiency, higher cost

Combined-cycle gas plants have traditionally been preferred as a baseload technology due to their higher efficiency. These plants utilize both a gas turbine and a steam turbine, significantly improving fuel efficiency compared to simple-cycle setups. While they are more expensive up front, their main advantage is generating more electricity from the same amount of fuel (which also results in a lower CO2 per MWh emissions rate).

However, complying with the upcoming limit of 100 pounds per MWh will require future baseload facilities to incur significant additional costs to mitigate carbon emissions, most likely through CCUS technology. CCUS technology also requires a large amount of auxiliary power, which would offset some of the traditional efficiency advantage of combined-cycle plants. For example, a 1×1 J-class combined-cycle plant with CCUS might generate roughly 750 megawatts (MW) of capacity with duct-firing but the auxiliary power requirements associated with CCUS might reduce the effective output to about 600 MW. While employing CCUS would allow the plant to continue operating as an unrestricted baseload facility, the economic impact of deploying carbon capture must be considered.

Alternately, utilities could forego the investment in CCUS and opt to build combined-cycle plants as intermediate load facilities, which then would be limited to a 40% capacity factor under the current rules. This decision would sacrifice a significant portion of the facilities’ potential energy production each year.

Simple-Cycle plants: Flexibility at a lower cost with trade-offs

Simple-cycle gas plants offer different advantages and trade-offs. They are generally cheaper to build and operate, with a less complex design and lower initial investment. Simple cycle plants are often used for peaking power, making them an attractive option for utilities needing to respond quickly to fluctuating demand.

From an emissions perspective, modern J-Class combustion turbines can meet the 1,170 pounds per MWh limit on their own. Given their lower output and efficiency, utilities are unlikely to invest in CCUS technology behind simple-cycle engines, which would put them in the intermediate load category.

In the case of simple-cycle plants, decision-makers must evaluate the levelized cost of electricity over the life of the facility. Simple-cycle plants have lower up-front costs, but efficiency would still be less than that of combined-cycle plants (even with CCUS), leading to higher fuel expenses over time. Utilities need to weigh whether the reduced initial investment would offset potentially higher operational costs, especially with fluctuating fuel prices.

A situational decision: Balancing needs and constraints

The choice between simple-cycle and combined-cycle gas plants is situational, depending on several unique factors for each project. For utilities seeking higher efficiency and baseload power, combined-cycle plants with carbon capture may be ideal, despite higher up-front costs. Conversely, utilities prioritizing flexibility and lower initial costs may find simple-cycle plants more advantageous for covering peak demand. Capacity needs are critical to the decision, and under the current rules there are more options to consider than ever before.

Graphic 1: Options for a hypothetical plant needing 600 megawatts of new generation.

As an example, if a utility needs approximately 600 megawatts (or 5,250 gigawatt-hours per year) of replacement generation, a combined-cycle setup could achieve this with fewer units and greater efficiency, while a simple-cycle approach would require multiple smaller units. The decision also depends on the utility’s anticipated emissions profile and willingness to invest in emissions-reducing technologies, like CCUS.

Additionally, utilities must consider other constraints, such as land availability, project timelines and financial resources, when making a decision. As lead times for acquiring equipment increase and regulatory pressures grow, it is essential to begin the decision-making process early and to thoroughly evaluate all variables.

Navigating complex choices

Unfortunately, there is not a clear choice between simple-cycle and combined-cycle gas plants under the updated NSPS. The decision depends on each utility’s specific needs, priorities and constraints. Combined-cycle plants offer higher efficiency and baseload capacity but come with significant costs, especially when incorporating carbon capture. Simple-cycle plants are more economical upfront but may struggle to meet future emissions standards.

Ultimately, utilities must balance efficiency, cost and compliance while staying attuned to regulatory changes. Engaging with peers, staying informed about technological advancements, and starting early are critical steps in successfully navigating these complex decisions.

Comparison chart: Simple-Cycle vs. Combined-Cycle gas plants


Originally published by Burns & McDonnell. See original article here.

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GE Vernova launches its first 100% hydrogen-fuelled aeroderivative gas turbine https://www.power-eng.com/gas-turbines/ge-vernova-launches-its-first-100-hydrogen-fuelled-aeroderivative-gas-turbine/ Tue, 26 Nov 2024 16:30:25 +0000 https://www.powerengineeringint.com/?p=148365 GE Vernova has announced that its LM6000 gas turbine is planned to operate on 100% hydrogen at the Whyalla hydrogen power plant in the Upper Spencer Gulf, South Australia.

The LM6000 gas turbine is part of the order secured with ATCO Australia for four LM6000VELOX units.

The announcement was made during a signing ceremony at COP29 attended by Ramesh Singaram, president and CEO of Asia, Gas Power, GE Vernova together with The Hon Peter Malinauskas, premier of South Australia and John Ivulich, CEO and Country Chair, ATCO Australia.

The commissioning of the turbine is expected in early 2026 and will mark the first time a GE Vernova power plant project, at commercial scale, is powered by aeroderivative gas turbine combustion technology capable of operating on 100% hydrogen.

GE Vernova’s aeroderivative gas turbine solution will be powered by renewable hydrogen generated at the Whyalla complex, which will include one of the world’s largest hydrogen production and storage plants.

When completed, the 200MW Whyalla hydrogen facility will act as a new source of firming capacity, providing additional grid stability to the state when renewable sources are not not able to meet demand.

Eric Gray, CEO of GE Vernova’s Gas Power business commented in a statement: “GE Vernova has been investing over the years in R&D to advance the capabilities of its combustion systems to burn higher blends of hydrogen. We are proud to unveil our first 100 percent hydrogen-ready aeroderivative gas turbine solution to support our customers’ decarbonization goals while maintaining grid reliability, which requires the deploying of renewable and conventional power technology in tandem.”

According to John Ivulich, CEO and Country Chair, ATCO Australia, deploying this solution will ultimately support South Australia’s decarbonization journey and aligns with the state’s goals outlined in the government’s Hydrogen Jobs Plan.

Said Ivulich: “With more than 70 percent of energy generated from renewable resources, South Australia is set to become a global leader in producing and utilizing renewable hydrogen and we are delighted to be part of this project that can unlock decarbonization opportunities.”

GE Vernova’s portfolio includes over 120 gas turbines that have the capacity to operate or currently are operating on fuels that contain hydrogen, producing more than 530TWh of electricity over 8.5 million hours.

Originally published by Pamela Largue in Power Engineering International.

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Biden EPA proposes stronger standards to regulate NOx from combustion turbines https://www.power-eng.com/gas/biden-epa-proposes-stronger-standards-to-regulate-nox-from-combustion-turbines/ Mon, 25 Nov 2024 17:59:07 +0000 https://www.power-eng.com/?p=127097 The U.S. Environmental Protection Agency (EPA) last week proposed to strengthen limits on nitrogen oxide (NOx) emissions from most new and existing combustion turbines.

The proposed New Source Performance Standards (NSPS) are based on the application of combustion controls and selective catalytic reduction (SCR).

EPA said the proposed standards would ensure that new turbines built at natural gas-fired plants or industrial facilities — especially large ones that could operate for decades — would be among the lowest-emitting turbines ever built.

To strengthen the NOx performance standards for new stationary combustion turbines, EPA is specifically proposing:

  • To determine that combustion controls with the addition of post-combustion SCR is the best system of emission reduction (BSER) for most combustion turbines. Post-combustion SCR is already widely used in the power sector.
  • To lower the NOx standards of performance for affected sources based on the application of the BSER.
  • To establish more protective NOx standards for affected new sources that plan to fire or co-fire hydrogen, ensuring that these units have the same level of control for NOx emissions as sources firing natural gas or non-natural gas fuels. 

The proposed standards would establish size-based categories based on base load heat input. The proposed size-based categories include:

  • Large combustion turbines — facilities with a base load heat input rating of > 850 MMBtu/h (> ~ 85 MW).
  • Medium combustion turbines — facilities with a base load heat input rating of > 250 and ≤ 850 MMBtu/h (> ~ 25 MW and ≤ ~ 85 MW). 
  • Small combustion turbines — facilities with a base load heat input rating of ≤ 250 MMBtu/h (≤ ~ 25 MW).

EPA is proposing to further subcategorize sources based on whether they operate at high, intermediate or low loads, as well as whether they burn natural gas or non-natural gas fuels. When classifying low, intermediate or base load units, EPA will consider the 12-calendar-month capacity factor of these combustion turbines.

  • High load — capacity factor greater than 40% (i.e., base load).
  • Intermediate load — capacity factor greater than 20% and less than or equal to 40%.
  • Low load — capacity factor of less than or equal to 20%.

For non-EGU stationary combustion turbines, the capacity factor would be determined based on the prior 12 calendar months of data on a rolling basis updated each month.

EPA acknowledged that SCR technology becomes less cost-effective and efficient at smaller scales or variable operating levels. Therefore, the agency is proposing standards for certain combustion turbines relying on combustion controls instead of SCR. This applies to small turbines at low or intermediate loads, and medium and large turbines at low loads.

The agency estimated the proposal would reduce NOx emissions by 198 tons in 2027 and 2,659 tons in 2032. The present value of net benefits to society is estimated at up to $340 million, with an equivalent value of up to $46.4 million per year. 

NOx contributes to harmful health effects, such as asthma and respiratory infections. Children, the elderly, and people with chronic heart, lung or other cardiopulmonary diseases are most at risk. 

EPA is also proposing to maintain the current limits for sulfur dioxide, which is well-controlled in the sector based on the long-term required use of low-sulfur natural gas and distillate fuels.

The agency last established New Source Performance Standards (NSPS) for stationary combustion turbines in 2006. The future of the proposal, as with other EPA power plant rules finalized in the last year, is unclear under the incoming Trump presidency.

EPA will accept comments for 90 days after the proposal is published in the Federal Register.

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EPRI, TVA conduct ‘world’s largest’ test of renewable diesel-fueled turbine https://www.power-eng.com/gas/turbines/epri-tva-conduct-worlds-largest-test-of-renewable-diesel-fueled-turbine/ Wed, 20 Nov 2024 18:37:08 +0000 https://www.power-eng.com/?p=127009 EPRI and the Tennessee Valley Authority (TVA) announced the successful demonstration of renewable diesel as a combustion turbine fuel for power generation.

The demonstration, which EPRI and TVA call the first U.S. test and the “largest conducted in the world,” was performed on a 76-megawatt (MW) dual-fuel natural gas/diesel unit at TVA’s Johnsonville site in Tennessee.

EPRI collaborated with TVA’s Innovation & Research and Johnsonville Operations teams to evaluate the gas turbine across a range of operating conditions, including at full load with no turbine or control system modifications. The companies argue the test demonstrated how renewable diesel could support near-term decarbonization of dispatchable thermal power generation assets, providing on-demand power with up to 75% fewer lifecycle greenhouse gas emissions compared to conventional diesel.

Renewable diesel is a fuel made from fats and oils, such as soybean oil or canola oil, and is processed to be chemically the same as petroleum diesel. It also meets the ASTM D975 specification for petroleum in the United States. Renewable diesel can be used as a replacement fuel or blended with any amount of petroleum diesel.

The past several years have seen “tremendous growth” in new renewable diesel plants, the Department of Energy (DOE) says, many of which are located in western U.S. states and were converted from existing petroleum refineries. The fuel is used primarily in California because of economic benefits provided under the Low Carbon Fuel Standard.

“As growing electricity demand underscores the continued need for dispatchable power generation, low-carbon fuels present a potential pathway for existing units to contribute to net-zero goals,” said Neva Espinoza, EPRI senior vice president of Energy Supply and Low-Carbon Resources and chief generation officer. “Collaboratively demonstrating emerging technologies and approaches at scale is key to accelerating a reliable and affordable energy transition.”

EPRI plans to soon publish a report outlining the demonstration’s results as part of the Low-Carbon Resources Initiative (LCRI) to both share details and learnings with industry and other stakeholders. The companies argue the demonstration could have industry implications for peaking units.

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Retrofitted gas turbine runs on methanol with 80% less NOx emissions https://www.power-eng.com/gas/turbines/retrofitted-gas-turbine-runs-on-methanol-with-80-less-nox-emissions/ Tue, 22 Oct 2024 19:24:39 +0000 https://www.powerengineeringint.com/?p=147766 Net Zero Technology Centre (NZTC) and Siemens Energy have successfully demonstrated the operation of an SGT-A35 gas turbine on methanol, reducing NOx emissions by 80% compared to traditional fuels.

The demonstration was carried out at the RWG facility in Aberdeen, UK, which provides maintenance, repair and overhaul services for Siemens Energy industrial aero-derivative gas generators and power turbines.

The SGT-A35 gas turbine was originally introduced to the market in the 1970s. Siemens Energy used 3D printing to manufacture the new components required for methanol fuel conversion, demonstrating the potential for retrofitting existing gas turbines for decarbonized operations.

Charlie Booth, project manager, NZTC commented in a statement: “Methanol’s unique properties make it an exceptional choice as a retrofittable, low-carbon alternative fuel and it is great that we are able to showcase the opportunity that exists in adapting existing infrastructure to meet our net zero targets and energy needs.”

The demonstrations are being delivered through NZTC’s Alternative Fuel for Gas Turbines project, one of seven projects under NZTC’s Net Zero Technology Transition Program (NZTTP).

This achievement builds on NZTC and Siemens Energy’s 2023 demonstration on the less powerful SGT-A20 turbine running on bio-methanol. This test showed CO2 emissions could be reduced by up to 75% when compared to conventional fuels.

Benefits of methanol

According to NZTC, one of the key benefits of methanol as an alternative to fossil fuels is that is can be produced from a variety of feedstocks. These include blue methanol, using carbon capture and storage, as well as bio-methanol or green hydrogen and captured CO2 (e-methanol).

Methanol produced from natural gas can reduce CO2 emissions by 10% compared to traditional liquid fuels and renewable methanol can cut CO2 emissions by up to 95%.

Methanol also reduces other emissions including NOx, PM, SO2 and smoke.

Originally published by Pamela Largue in Power Engineering International.

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Evergy to build two new combined cycle gas plants in Kansas https://www.power-eng.com/gas-turbines/evergy-to-build-two-new-combined-cycle-gas-plants-in-kansas/ Tue, 22 Oct 2024 18:03:18 +0000 https://www.power-eng.com/?p=126524 Evergy plans to build two new 705 megawatt (MW) natural gas combined cycle (NGCC) plants in Kansas.

The two units, one in Sumter County and the other in Reno County, would come online in 2029 and 2030, respectively. The plants would cost more than $2 billion total to build and would operate for 40 years.

Utility officials said the new units would support reliability as the region faces significant electricity demand growth. They said dispatchable natural gas would complement the utility’s growing number of wind and solar resources.

Demand for electricity is rising in much of the U.S., driven by new manufacturing facilities for batteries and semiconductor chips, as well as data centers.

“Kansas is experiencing record economic growth, and Evergy is prepared to deliver the reliable, affordable, and sustainable energy needed,” said Evergy President David Campbell.

Earlier this year, Evergy updated its Integrated Resource Plan, projecting an additional 1,900 MW of capacity need over the next 20 years compared to just one year earlier in 2023. During that same period, Evergy would retire more than 4,500 MW of coal generation.

Over the next 20 years, Evergy projects it will need to add 5,100 MW of renewable energy from wind and solar and 6,000 MW of firm, dispatchable generation – including 2,500 MW of new natural gas generation across 2029-2032.

Today, almost half of the power generated by Evergy comes from emission-free sources, including the Wolf Creek nuclear plant and renewable energy sources. The company has reduced its carbon emissions by more than 50% since 2005, progressing towards the interim goal of a 70% reduction in owned generation carbon emissions from 2005 levels by 2030.

Evergy is targeting to achieve net-zero carbon equivalent emissions, for scope 1 and 2, by 2045 through the transition of its generation fleet. Achieving these emissions reductions is expected to be dependent on enabling technologies and supportive policies and regulations, among other external factors, Evergy said,

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Critical maintenance: Combustion turbine outlet duct upgrades at a simple cycle plant https://www.power-eng.com/om/retrofits-upgrades-om/critical-maintenance-combustion-turbine-outlet-duct-upgrades-at-an-idaho-simple-cycle-plant/ Thu, 12 Sep 2024 17:57:39 +0000 https://www.power-eng.com/?p=125683 Simple cycle power plants are an integral part of our current electrical generating network, as they can be quickly started and stopped to follow renewable energy load swings or to address peak load needs. The high temperatures generated by combustion turbines and the common on-and-off cycling of these units induce thermal and mechanical stresses within the turbine exhaust system in components such as duct liners, silencers, and support brackets. Regular maintenance is important, as this article explains.   

Some simple cycle design basics

Anyone who has flown in a modern commercial airliner has experienced the effects of combustion turbines. Jet engines, of course, generate thrust for flight, whereas in power units, the energy drives a stationary turbine to provide the mechanical energy for an electrical generator. An outlet duct and stack convey the turbine exhaust gas to atmosphere. Important components within the exhaust system include internally lined ductwork and stacks and silencers. Noise regulations are common for simple and combined cycle plants, as many facilities are located within or near residential areas.  Silencers reduce noise levels below local guidelines. Ducts also typically have an internal liner to inhibit transient heat transfer through the duct walls. 

The combustion products that power gas turbines reach very high temperatures, perhaps up to 2,700o F. Even though much of this energy is utilized by the turbine generator (and to drive inlet air compressors), the exhaust gas temperature may still exceed 1,100o F. The hot exhaust gas and the wide temperature ranges that occur from unit load cycling place much stress and wear on the outlet duct and internal components. Periodic inspections and maintenance are necessary to keep this equipment in reliable condition.   

The following list outlines critical outlet duct and stack maintenance issues that developed over time at the plant highlighted in this article:

  • Repair of silencer baffles and support brackets
  • Replacement of failed internally lined exhaust system sections
  • Installation of new test ports (depending on condition and new silencer design)
  • Repair of cracks in the casing

Solutions

Following a complete system survey, the maintenance contractor, SVI BREMCO, addressed each of these issues and others during a several-week maintenance outage. A primary task was to replace the silencer baffles and support brackets. SVI BREMCO replaced the traditional parallel baffle silencer design with a proprietary bar silencer design. The bar silencer design is very popular for simple cycle exhaust system retrofits because it provides better acoustics, reduces pressure drop (better turbine performance and project ROI), and optimizes aerodynamics (improving durability).

This work required coordination of multiple personnel, including equipment specialists, welders, crane operators and safety personnel. These specialists also installed new test ports and made duct liner repairs during the outage window.

Figure 2. New test ports.

Testports are critical for flue gas monitoring, including flow dynamics. Adjustments to test port location can often improve monitoring capabilities. Installation of new ports was a key part of this project, along with improved silencer design, as was the installation of liner material at these locations.

Figure 3. New test port liner installation. The SVI BREMCO website includes additional posts that provide information about more extensive liner replacements.

The maintenance crews also repaired duct/stack metal cracks in the casing. The peaking nature of simple cycle operation places much cyclic stress on liners, which in turn can cause cause liner failure and cracked casing. Cracks that breach welds or duct walls allow flue gas to escape. Once cracking begins, the damage typically continues to propagate.

Figure 5. Stack weld repair.
Figure 4. Transition duct cracking before repair.


The crews also repaired a crack in a generator lubricating oil line, whose discovery came from inspections apart from those of the duct and stack. As this author can attest from direct experience, maintenance issues may stay hidden without thorough inspections conducted per detailed procedures.

Safety – The overall critical issue

No matter how competently maintenance personnel and contractors perform the work, the foremost concern is that everyone arrives home safely at the end of the day. A sampling of the topics discussed during SVI BREMCO safety meetings (conducted at the start of each shift) includes fall protection, electrical safety, hot work issues, and lock out/tag out (LOTO) procedures.  
 
Conclusion

Even though a large amount of the energy generated in a simple cycle power plant is converted to mechanical energy in the combustion turbine, the exhaust duct, duct liners, silencers, support brackets, and other components are still subject to harsh conditions. As with all equipment, these components degrade over time and require maintenance. SVI BREMCO has a highly experienced staff to evaluate and offer solutions for these and many other simple and combined cycle maintenance needs. Contact information is available on the company website.
 
Industrial Contracting Services for HRSGs- SVI BREMCO (svi-bremco.com)


About the Author: Brad Buecker is president of Buecker & Associates, LLC, consulting and technical writing/marketing. Most recently he served as a senior technical publicist with ChemTreat, Inc. He has many years of experience in or supporting the power industry, much of it in steam generation chemistry, water treatment, air quality control, and results engineering positions with City Water, Light & Power (Springfield, Ill.) and Kansas City Power & Light Company’s (now Evergy) La Cygne, Kan., station. His work has also included eleven years with two engineering firms, Burns & McDonnell and Kiewit, and he spent two years as acting water/wastewater supervisor at a chemical plant. Buecker has a B.S. in chemistry from Iowa State University with additional course work in fluid mechanics, energy and materials balances, and advanced inorganic chemistry. He has authored or co-authored over 250 articles for various technical trade magazines, and he has written three books on power plant chemistry and air pollution control. He is a member of the ACS, AIChE, AIST, ASME, AWT, CTI, the Electric Utility Chemistry Workshop planning committee, and he is active with the International Water Conference and POWERGEN International.

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