Datastream | Convert | ProcessBook

Oct Exec Summary 03

small logo

Executive Summary
October 2003


Mesquite Generating Station Block 1 produced 127,377 MW in October. Based on dispatched power of 145,960 MW, the Technical Availability Factor was 87.2%. The Facility was dispatched for 15 days and operated 16 hours at peak fire. The following statistics are recorded for the month: Capacity Factor 28.95%, Availability Factor 47.37%, Equivalent Availability Factor 43.2%, and Forced Outage Factor .41%. Block Net Heat Rate averaged 7252 for the month, resulting in an Efficiency Rating of 101.1% at seasonal temperature adjustment.

A maintenance outage was taken from October 4th through October 19th to accomplish (BVZ) pre-warranty commitments. Critical path was based on a 14-day requirement for BVZ to replace the STG3 condenser expansion joint. Additionally, John Zink Corporation completed repairs to HRSG 1 and 2 duct burner runner supports and also performed “tuning” of the duct burner tips on these units. Alstom was onsite to make repairs to all Mesquite 230 kV circuit breakers, a manufacturer's defect that was found to be root cause for the August 29th issue on the STG3 A-phase breaker. Ionics assisted Mesquite personnel in correcting installation issues on the BWRO and Demin/RO units and to perform RO cleaning. Ionics also initiated a warranty claim to correct flow specs on the Mesquite inlet sand filters, found to be fouled due to low (BVZ design) setpoints. Airnetics assisted Mesquite personnel in completing Air Compressor PM's, discovering a failed bearing on C compressor. This compressor is critical equipment, being the only unit on the 12 kV reliable power bus. During the outage, GE installed software upgrades to mitigate Stage 17 compressor failure and to correct communication issues between the MKV and DCS. Also, inspections of the two units found cracked Inlet Bleed Heat manifold supports that were repaired by GE Field Services. GE installed balance shots on GT1 and STG3 to correct cold start vibration issues.

A short-duration Forced Outage occurred on October 21st due to a GT runback on high HRH steam temperature. From October 25th to October 31st, GT1 incurred 7 successive trips due to yet undetermined conditions, causing 30.8 hours of Unplanned Derate Hours. GE Powers Systems has provided core engineering support to address this issue and continues a root cause investigation. Starts reliability on both GT1 and GT2 remains at 100%.


Mesquite Power logged 8361 work hours for October, a peak month due to outage support requirements. No Reportable or Lost Time Injuries were recorded.

On October 23rd, an Electrician for Zachry Construction Corporation was fatality injured when he came in contact with an energized 277 V lighting circuit. This incident remains under investigation.


Mesquite Generating Station submitted ten Air Permit Exceedance Reports in October, seven reports for GT1 and three for GT2. All reports were related to start-up and/or trip recovery emission above the allowable per our permit. The Air Permit significant revision is now under public comment until November 19th, at which time the final draft will be reviewed by Maricopa County.

Reports submitted in October included the quarterly CEMS EDR's for GT1 and 2, the Air Permit semi-annual compliance report, the ADEQ quarterly Self-monitoring Report for Evap Pond A, and the quarterly EQR report to FERC. Block 2 CGA, linearity, and RATA testing were also completed in October.


Tolling Revenue for the month of October totaled $668,000. Following deduction for replacement power costs associated with Block 1 schedule deviations, Mesquite Power ended October with a Gross Loss of $102,000.

Budget variance on the October Balance Sheet shows negative $1.6 million, attributed primarily to the Synthetic Lease payment and interest that were not included in the 2003 budget. Variable O&M costs are $155,000 below budget due to the reclass of waste services and well electric costs to the appropriate Mesquite plant systems. Actuals for plant systems increased over budget correspondingly and include charges for Block 2 chemicals and the October outage preparations.

LTSA fixed costs for October were above budget due to escalation adjustments from previous payments. Prepaid amounts for the variable portion are found in the LTSA report and reflect the October outage hours deviation.


Mesquite performed major annual PM's during the two week outage to include cooling tower fan oil change, air compressor annual maintenance, and Fire Suppression and detection system PM's. Numerous leak issues were resolved, most notably 8 HRSG drain valves that were cut out and replaced with dual valves. Improved designed drain valves can later be installed downstream without breach of the B31 code boundary. New design neat feed pumps were installed for amine and HRSG phosphate on Block 1, and cross-connects for clarifier sludge forwarding and recirc were installed. A bypass for RO reject to the surge tank was installed inline with a diverted surge tank overflow to the waste water sump. This line will be placed in service once the second APP modification is approved by ADEQ.


Ionics helped identify a significant flow throughput issue with the Lime filters installed upstream of the BWRO units. BVZ designed and set the backwash flowrate to prevent loss of the Fire Water tank below the NFPA level, essentially depriving an adequate backwash of the filters. We are now working with BVZ engineering to resolve this issue with increased frequency testing.

Clarifier performance testing occurred in October using Nalco Sodium Aluminate product and Tramfloc organic polymers. Both companies were permitted to run similar tests on Clarifier A while unit B was dedicated to production. Unfortunately, neither test resulted in a positive indication of success. While Mesquite personnel continue to find the optimum balance of solids and silica, we are cognizant of the AMA cycles requirement on the cooling towers once Block 2 is commercial. We are currently investigating other cooling tower inhibitors that may allow greater soluble silica levels to help us achieve higher cycles of concentration.

The GT1 trip issue remains unresolved, yet this unit has not tripped for the same reason since it was restarted on Nov 1st. All operating software was restored to the original, pre-outage configuration, the P2 pressure transmitter and SRV servo were replaced, and several instruments were recalibrated. Given all the collected data, GE was unable to conclude the root cause for these consecutive events, each having nearly identical scenarios. Investigation continues.

Facing us as early as next spring will be a lack of Service and demin water capacity to support full operation of Mesquite Power. With the observed actual operating cycle make-up requirements, there remains no margin for peak operation, unrecoverable losses, chemical make-up, sampling, or maintenance. System design was based on a .5% cycle make-up rate at all load ranges. Chemical suppliers publish that high purity make-up systems should be capable of system optimization targets of 1% blowdown during steady state operations. The Mesquite Power LLC supplier Nooter Erickson recommends a target of ‘better than 2%'. At this time, based on the present installed equipment and including normal losses, the make-up requirement with a 1% blowdown target is greater than the installed equipment capacity. As efforts continue to commission Power Block 2, we are seeing increased periods where the capabilities of the Demin/RO systems are challenged and have experience two occasions where trailer support was required to supplement routine evolutions and one period where three days of production were lost due to make-up inability following a system related upset. Originally considered an acceptable plan to support commissioning efforts, excess Demin water was to be made available for commissioning and operations of Block 2. At this time, there have been no significant periods where excess Demin capacity has been available to support Block 2. BVZ Start-up has relied exclusively upon Demin Trailer (vendor) support. Mesquite Power is proceeding with a capital project proposal to upgrade the current system to meet actual water demands of the Facility.

Mesquite Power continues to submit Air Permit (start-up emissions) Exceedance Reports for every Gas Turbine start, now including Block 2 units. Though we have not received any additional Air Permit Notice of Violations since the nine issued by MCESD in June 2003, we have submitted over 30 Exceedance reports since May. Final approval of the modified Air Permit conditions allowing higher start-up levels is unknown at this time.


About Us | Email Settings | Policy Manuals | Email Control Room