O&M begins well before first fire

Non-utility combined-cycle facilities often have separate entities for ownership, EPC services, onsite O&M, and long-term care of the gas turbines. While this arrangement may create efficiencies within each function, it can also create gaps among the organizations involved. One of the most important of these gaps occurs as construction winds down and commissioning ramps up.

Most CCJ readers are probably familiar with owner and/or O&M teams that lament the lack of collaboration with the EPC team after they become mired in consequential issues (and often litigation) which could have been addressed ahead of time. As more facility revenue is earned through performance-based market objectives, avoiding impacts to productivity, reliability, and flexibility becomes paramount.

At the soon-to-be completed Woodbridge (NJ) Energy Center, the operator of record, Consolidated Asset Management Services, created a formal process of walk downs, the intention being, according to CAMS’ Ken Earl (and Woodbridge plant manager), to “own” the operation of the facility from Day One. What he means by “own” is to not be in a position of blaming someone else for punch list items after commissioning.

Woodbridge will not be the first plant with GE 7FA.05 gas-turbine operation under its belt, but it will be one of three facilities with the earliest industry experience. The sexy advanced GT technology may hog the attention, but it’s the mundane components that can bite where it hurts when neglected.

Trust but verify. The CAMS team was put in place and onsite eight months prior to first fire expressly to provide input to construction and EPC. As the EPC construction team completed sub-systems, they would be turned over to the EPC startup and commissioning team. The turn-over process required a formal walk down of the subsystem to ensure construction was completed in accordance with design specifications and that the system was ready for operation.

CAMS became involved with the turnover process and organized and implemented a formal process to be used when reviewing systems with members of the construction trades, EPC startup team, and owner representatives. The key objective was to understand how the systems were supposed to have been built and then make sure the facts on the ground reflected the design.

CAMS assembled a package for each walk down, including P&IDs, one-line diagrams, design specifications, equipment supplier specifications, and installation procedures. To ensure they were well-versed in the finer points, CAMS conducted a pre-walk down of its own before the formal walk down with all stakeholders.

In this way, CAMS identified issues falling through the gratings. Heat tracing is an excellent example, according to the plant manager (PM). Woodbridge is an “outdoor” plant in New Jersey, so inadequate installation of heat tracing would impact winter reliability and availability. The PJM power market, where Woodbridge will feed its output, imposes stiff penalties (up to millions of dollars a day) on plants that do not meet their performance obligations in the capacity market. Thus, heat tracing becomes a critical plant subsystem.

The following are CAMS’ most notable discoveries from the walk downs:

      • A large motor-operated isolation valve in the cold reheat system was installed in an obstructed location which would have prevented disassembly because of interference with structural steel.

      • Double-walled aqueous ammonia piping was installed with no means of inspecting the interstitial space. The facility drawings indicated inspection ports had been installed to facilitate inspections of the containment pipe; however the carrier pipe (ammonia) was brought above grade to a blind flange. This was identified during a compliance audit prior to ammonia being placed in the system but could have resulted in a serious safety and environmental event.

      • The non-segregated phase bus duct between a 4160-kV transformer and the switchgear building was blocking access to inspection doors on the primary switchgear feed, prohibiting routine inspections.

      • A boiler feedwater flow element was installed backwards by the EPC.

      • Interconnecting piping for the reverse-osmosis (RO) units in the water treatment plant was installed in a location that would prevent or inhibit loading or unloading of RO membranes.

      • The auxiliary-boiler feedwater storage-tank drain line was installed without an isolation valve, which could lead to inadvertent, continuous draining.

      • Eyewash/shower stations were not in compliance with ANSI standards.

      • Over 90 instances were identified of guardrails, handrails, and fixed ladders non-compliant with OSHA standards.

      • Heat detectors in the gas-turbine-housing accessory compartment were improperly located against their design temperature ratings. In this case, the equipment was supplied directly by the turbine OEM, underscoring the importance of repeated quality checks.

      • The cold-reheat desuperheater intermediate-pressure feedwater lines had no means of isolation from the common feedwater line supplied from each HRSG (which would prevent a single unit outage).

      • Similarly, the common condensate feed line to the low-pressure economizers had no means of isolation from the common line supplying each HRSG, which also would prevent a single unit outage.

In addition, there were literally hundreds of “little things” involving equipment access, construction quality, and design shortcomings which were identified based on prior startup experience at other facilities. “We pushed back on many items,” PM Earl said, “because we treat the asset as our own. Our goal is to ensure all deficiencies are identified and addressed during construction so there are zero punch-list items on day one of commercial ops.”

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