Case Study



Throughout 2017 and 2018, environmental concerns and economic realities have precipitated the shut down of nearly 24,000 Megawatts of solid-fuel, coal-fired generation. The trend will continue with at least 33 more units of greater than 100 MW expected to cease operations by the end of 2021. Electric Utility companies are faced with the challenge of keeping these units operational until their scheduled shut-down dates while simultaneously re-assigning plant Operations and Maintenance personnel to other facilities within their respective systems. One possible solution for Utilities is to supplement their permanent O&M personnel with contract personnel. This paper describes Sentinel-TDS’s experience providing supplemental contract O&M personnel to a 3-Unit, 2250 MW, super-critical coal-fired generating station in Northern Arizona.


In February 2017, utility owners of the nearly 50-year old plant decided to end their participation when the current term of their lease ends in 2019, in part because it became clear that current and forecasted natural gas prices had made coal-fired generation from this station uneconomical. For example, plant costs and retail market performance were studied by National Renewal Energy Labs (NREL) for the plant owners. Their cost-vs.-revenue indicated a negative cash position for the remaining life of the plant. Nevertheless, from the time of the announcement until early 2019, a number of potential suitors investigated the possibility of purchasing the plant and prolonging its operation. To help provide visibility and information about the plant, the principal owners hosted numerous tours of the plant for prospective buyers, elected officials, regulators, and federal government officials. Despite numerous short-and-long term cost optimization strategies proposed by Sentinel-TDS and others, the prospective buyers ultimately determined that the risk/reward quotient did not support the feasibility of plant purchase and ongoing operations. Once the owners had made the decision to divest themselves of the plant, they made a commitment to redeploy all their employees who desired it to other facilities within their system. How to accomplish this goal while simultaneously operating the plant until its scheduled shutdown date of December 2019? After due consideration, the owners decided to supplement their in-house Operations and Maintenance staff with contract personnel.


A contract and purchase order to supply Auxiliary Operators and E&I Maintenance Technicians was awarded to Sentinel-TDS in April 2017 pursuant to meetings and negotiations with the Owner’s Management Team. The first four Sentinel-TDS personnel mobilized in July 2017. Staff size grew slowly throughout 2017. Beginning in Q2, 2018, the Owner began a more aggressive redeployment of in-house employees, leading to a rapid expansion of Sentinel-TDS’ staff to its current level.
In the initial discussions with the Owner’s Management Team, it was anticipated that a total of 60 Sentinel-TDS personnel would be retained. We reached that quota in Q3 2018 and have maintained our staff size at 60 +/- 5 until the present time.


Throughout most of 2017, all Sentinel-TDS Operations personnel were hired and placed as Auxiliary Operators, working in the power block, ash-handling, S02 scrubber, and waste-water treatment areas. This was by design as the Owners had some trepidation regarding allowing contractors with relatively brief operating experience in the plant to operate from the Control Room. However, as the Owner’s began to re-deploy their in-house Control Room Operators (CRO), it became clear that Control Room Operations would have to be supplemented by contractors to keep the units on line. To this end, the Owners began training contractors who had demonstrated the requisite plant knowledge and general competence. The training included three weeks in the plant’s simulator facility, followed by approximately three weeks as a trainee working in the Control Room under the supervision of a qualified in-house CRO. Sentinel-TDS now has Control Room Operators assigned to all shifts in all units. Meanwhile, we continue to recruit and provide Auxiliary Operators as requested by the Owners to replace their departing staff personnel.


The Owner’s initial requirement for Sentinel-TDS was to provide four I&C Technicians to supplement the plant’s I&C Maintenance Department. The I&C Technicians perform routine calibration checks and troubleshooting on process system instrumentation and control loops throughout the plant. In addition, they replace damaged instruments, disassemble and repair control valves, air-operated block valves, and motor-operated valves, and support planned and forced outages as required. Sentinel-TDS now supplies a total of seven I&C Technicians.
In early 2018, the Owners asked Sentinel-TDS to provide two DCS Technicians. The DCS Technicians modify control logic, tune process control parameters, and monitor DCS/PLC network health as required. Around the same time, the Owners asked Sentinel-TDS to provide Maintenance Planners. Sentinel-TDS retained three planners with Primavera P6 and Maximo expertise to support the Owner’s outage requirements. Finally, Sentinel-TDS has supplied to Journeyman Electricians to provide cable testing, switchgear and motor control center testing and repair, motor removal and reinstallation, battery maintenance, ground fault isolation, and battery charger/UPS inverter troubleshooting and maintenance.


All Sentinel-TDS personnel supplied to this client have prior coal-fired power plant operating and/or maintenance experience. By early 2019, our personnel had more years’ super-critical, coal-fired boiler operating experience the Owner’s in-house personnel. Our personnel were recruited from several sources. Many of the operators came from plants across the country that had recently shut down. Experience on this project has shown us that there are many highly-qualified and motivated former coal-fired power plant operators available to supplement a plant’s in-house staff. We (and the Owner’s Management) have also learned that these operators can quickly learn the new plant and provide competent and reliable shift coverage with minimal supervision. In addition, Sentinel-TDS worked with the Owner to transfer or retain personnel who

  1. were currently working at the plant and near retirement or
  2. were recently retired and wished to return to finish out their careers in the familiar environs in which they had worked for many years.

Several of the maintenance technicians and planners were recruited directly by Sentinel-TDS from our substantial data base of current and former employees. Others were recruited from the same sources as the operators, i.e. recently shut down plants from elsewhere in the US or retirees from the Owner’s plant.


Sentinel-TDS now has a cadre of well-qualified, highly skilled, recently-proven coal-fired power plant operators and maintenance technicians available for assignment anywhere in the US. Further, we’ve become adept at finding and recruiting new talent from other shut-down coal-fired stations, as well as collaborating with clients to retain their valued personnel who are retired or near retirement.
After shutdown, we can assist with pre-demolition activities such as system drainage or layup, electrical de-energization, pond/waste water treatment, and asset recovery. In addition, we may be able to assist with placement of our clients’ personnel who were laid off pursuant to the plant’s shutdown. Sentinel-TDS is a “one-stop-shop” for providing personnel who can facilitate an orderly transition from unit/station normal operation to final shutdown and beyond for our clients.