BEST PRACTICES: Lea – Combined Cycle Journal


Cooler enhancement for instrument air compressor

Challenge. Lea Power Partners’ combined cycle was designed with dozens of air-operated valves (AOVs) to enable reliable remote valve operation; two 100%-capacity, 407-cfm compressors provide instrument air for AOV operation. The compressors were susceptible to shut down on high temperature in summer, interrupting air flow to the AOVs and potentially tripping the plant.

Solution. Staff purchased and installed radiators for the air compressors, tapping into the existing plant chilled water system for cooling water. Fans were installed in front of the radiators, shrouds were fabricated to maximize air flow across the radiators.

Results. Chilled water flowing through the radiators in summer has reduced the operating temperature of the compressors, eliminating high-temperature trips.

Project participants:

Roger Schnabel, plant manager

Richard Shaw, O&M supervisor

Kelvin Mendenhall, senior mechanical tech

Cybersecurity safeguards prevent control-system breaches

Challenge. Cybersecurity attacks on powerplant computers and PLCs from hackers have been increasing each year. Flash drives, DVDs, and CDs used by plant personnel and contractors are bypassing the firewalls set up to protect the computer servers used for the plant’s DCS or for systems that require a data acquisition system for the recording of operational data and the storage of files—such as for a continuous emission monitoring system (CEMS).

These devices may be carrying malware capable of disabling plant systems or allowing hackers to control them. Additionally, the design of the stick flash drive is such that it could be filled with a bank of capacitors that when inserted into a USB port, could charge the capacitors and allow a large capacitance discharge that could destroy a server’s hard drive.

Contractors must be allowed to access the plant’s servers for collection of data during testing. Data collected on portable media could be sensitive and must be protected should a flash drive be lost with encryption and password protection.

Solution. To protect the plant’s vulnerable digital systems from being manipulated by hackers, a variety of safeguards have been implemented at Lea:

  • Allow use onsite of only one specific kind of flash drive.
  • Train all contractors and site personnel on the use and design of this specific flash drive, so they can identify it by sight prevent another type of flash drive from being used.
  • Train all personnel on the encryption of files stored on the designated flash drive to protect data in case a flash drive is lost.
  • Set up kiosks to verify that the flash drives, DVDs, or CDs that will be used on the plant’s servers are malware-free before using them.

Results. Hackers are prevented from interfering with critical computer servers.

Project participant: Michael Barnett, regulatory specialist

GT upgrade yields significant operational improvements

Challenge. Improve plant output and efficiency to meet a growing need for gas-fired combined-cycle power.

Solution. During a scheduled gas-turbine major inspection (MI), Lea Power Partners engaged OEM Mitsubishi Hitachi Power Systems Americas to install the company’s F4 upgrade on Lea’s two M501F GTs. The upgrade includes an advanced thermal barrier coating and a new cooling design for Row 1 and R2 turbine blades and vanes to increase power output.

R1 compressor blades also were replaced during the scheduled MI, upgrading the existing double-circular-arc airfoil design with the latest multi-circular-arc design.


  • Improved simple-cycle output by an average of 7%.
  • Improved the simple-cycle heat rate by an average of 1.5%.
  • Improved combined-cycle output by 3.25%.
  • Improved combined-cycle efficiency by reducing net plant heat rate by 2%.

Project participants:

Roger Schnabel, plant manager

Richard Shaw, O&M supervisor

David Baugh, asset manager

Todd Witwer, EVP western operations

Lea Power Partners LLC

Owned by FREIF North American Power I LLC
Operated by Consolidated Asset Management Services
604-MW, gas-fired, 2 × 1 combined cycle (501F) located in Hobbs, NM
Plant manager: Roger Schnabel

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