Extending 7FA rotor performance, without the OEM price tag
How EthosEnergy helped Doswell stay online with a smarter 7FA rotor replacement
- Goals
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- Avoid costly OEM replacement
- Deliver fast despite a tight schedule
- Tailor the solution to the plant’s operational profile
- Replace an aging 7FA rotor nearing end-of-life
- Sectors
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- Power generation
- Asset
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- Heavy Gas Turbines
- Location
- United States
An aging asset with a tight deadline
Doswell Energy Center faced a major hurdle.
Their CT1 rotor had reached the OEM-mandated limit of 5,000 starts. With no OEM life extension option documented for this configuration, the customer would typically need to pursue a full rotor replacement.
A full rotor replacement is often a significant investment, which could cost millions and often involves long lead times that can push maintenance plans far into the future.
Given Doswell’s role as a peaking facility, where starts matter more than hours, it was crucial to align the outage with their schedule and operation needs to avoid unnecessary strain.
They needed a solution that balanced performance, compatibility, and speed.
Key Points
- Delivered a Certified Previously Operated (CPO™) Rotor with 4,800 starts and 48,000 hours remaining
- Converted a flared seed rotor to an unflared design to match unit specs
- Completed full teardown, inspection, and rebuild with minimal lead time
- Delivered substantial cost savings compared to OEM alternatives
- Maintained open, transparent communication throughout process
A tailored rotor with the right life, right fit – at half the cost
The owner came to EthosEnergy as a trusted partner who recommended a Certified Previously Operated (CPO™) rotor, selected to align precisely with Doswell’s operational profile, focused on high starts and low hours.
The expert team sourced a rotor from a baseload unit with around 300 starts and 144,000 hours.
Through EthosEnergy’s advanced life extension process, it was transformed into a CPO rotor capable of delivering 4,800 starts and 48,000 more hours – more than enough for two decades of peaking service.
To ensure fit and performance, the team also:
- Converted the seed rotor from flared to unflared
- Replaced flat-bottom blades with a more robust round-bottom design
The end result was a fully certified, tested, and compatible rotor that delivered substantial savings without compromising quality.
Precision inspections, real-world decision-making
EthosEnergy carried out full rotor disassembly and inspection, including:
- Visual and NDE inspections
- Dimensional checks and 3D scanning
- Blade profiling and component balancing
Every step was guided by the plant’s future operating conditions to make certain that the final assembly was both mechanically sound and also tuned for the site's start-heavy operation.
The flared-to-unflared conversion and hardware updates were executed in-house, backed by the proprietary knowledge of 7FA configurations and rotor design variation.
Relentless execution fueling customer success
From inspection start to delivery, the project took just under a year – with the reassembly and shipping window coming down to the wire.
Every compressor blade, bolt, and fastener was weighed, balanced, and installed to OEM-grade precision, which is critical for an asset spinning at 3,600 rpm.
EthosEnergy coordinated every aspect in-house, from engineering and parts to logistics and customer updates. Crucially, the outage schedule was kept intact – something the customer couldn’t have achieved within the same timeframe via more traditional channels.
What truly sets EthosEnergy apart though is the way they work. Their teams bring creativity, collaboration, and a relentless mindset to every project – adapting in real time, solving problems as they arise, and always moving together toward the customer’s goal.
A future-proofed unit, ready to run for another two decades
Thanks to expert engineering, relentless work, and fully communicative teamwork, EthosEnergy helped Doswell:
- Avoid the high capital expenditure of a new OEM rotor
- Receive a rotor with nearly full life reset
- Meet outage timing without delays
- Plan long-term maintenance with confidence
And with transparent communication, milestone-based financing, and a team that adapted to every twist, EthosEnergy proved once again why they’re the trusted partner for asset life extension.
Find out more
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Heavy Gas Turbines
The largest independent provider of heavy gas turbine repair and maintenance services – with specialised expertise in GE frame units, including 7F, and OEM capabilities for Fiat Avio and mature Westinghouse turbines.
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Rotor Life Extension
Proven and reliable gas turbine rotor end of life solutions for aging fleets, including heavy duty gas turbine GE frame B, E, and F class as well as mature Westinghouse units. EthosEnergy’s solutions have been engineered to meet or exceed the original equipment manufacturer and the recommended end of life.
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