HomeMy WebLinkAboutA001 - Council Action Form dated August 25, 2026ITEM #:22
DATE:08-25-26
DEPT:ELEC
SUBJECT:COMBUSTION TURBINE CONTROLS UPGRADE - CHANGE ORDER NO. 4
COUNCIL ACTION FORM
BACKGROUND:
The Electric Services Department operates two combustion turbines to provide electricity to
meet the utility's capacity obligations, produce energy during times when market rates are
high, and to provide black start capability in the event the utility is entirely cut off from the
regional transmission grid.
The existing controls systems on Combustion Turbines 1 (CT1) and Combustion Turbine 2
(CT2) are outdated and are in need of replacement. The hardware, software, system
architecture, and several pieces of instrumentation are antiquated. Replacements are difficult
to find and generally the systems no longer reflect best industry practices. Electric Department
staff worked with AP4 Energy Services, LLC to develop a specification for acquiring a
combined updated controls system for both combustion turbines.
During the development of the specification and review of the existing infrastructure, it
was also determined the existing motor control center (MCC) for CT1 needed to be
updated. The existing MCC utilizes a proprietary communications protocol that is no
longer supported by the manufacturer and replacement parts are difficult to acquire,
with only used parts available.
On August 12, 2025, City Council awarded a contract to Petrotech Inc., of New Orleans, LA,
for the Combustion Turbine Controls Upgrade project in the amount of $1,213,252.67.
CHANGE ORDERS:
Change Order No. 1 was approved by City Council on October 28, 2025, in the amount of
$174,300.86, to add additional controls equipment to CT2 for better unit control and to change
the control system network architecture to a centralized network for simplified maintenance
and increased reliability as identified by Petrotech.
Change Order No. 2 was approved by City Council on January 13, 2026, in the amount of
$176,054.59, for replacing the servo controllers and valve positioners for engine control and
replacing instrumentation on critical process systems on CT2, and replacing the level
transmitter in CT1's lubricating oil system.
Change Order No. 3 was approved by staff in the amount of $40,575.47 for the engineering,
drafting, programming, testing, project management, and shop services required to integrate
an engine oil recirculation system for Combustion Turbine 1. Plant personnel are acquiring
additional equipment and performing installation services for this equipment to reduce costs.
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THIS ACTION:
Change Order No. 4, in the amount of $10,039.81 (inclusive of sales tax), is being
requested by staff for the engineering, programming, and shop services required to
provide additional control logic for CT2. This type of generator control is available with
CT1 but has not been available for CT2.
There are periods of operation, specifically during startup, where the VAR value
experienced by the generator is negative, which can be damaging to the generator and
cause grid instability. Incorporating more sophisticated control logic to CT2 will allow
the electric utility to respond to dynamic grid conditions more readily with CT2 and
reduce wear, increasing the reliability of the generating asset.
The amount of this change order, when combined with the previous change order, exceeds
the threshold that can be approved administratively by staff. Therefore, City Council action is
required to approve the change. With this action the total contract amount will be
$1,614,223.40. There is currently $203,263 in the CIP budget for this project that is
available to fund this change order.
ALTERNATIVES:
1. Approve Change Order No. 4 with Petrotech Inc., of New Orleans, LA, for Combustion
Turbine Controls Upgrade in an amount of $10,039.81 (inclusive of Iowa sales tax).
2. Do not approve the change order.
CITY MANAGER'S RECOMMENDED ACTION:
The control logic for Combustion Turbine 2 does not include the same sophistication
as the control logic for CT 1 to prevent reliability issues with the unit during startups
and periods of dynamic grid conditions. The recommended changes from Petrotech
will provide additional control logic, which will enable Power Plant staff to operate CT2
in periods of grid instability and reduce generator wear, thus increasing asset
reliability. The items listed in this Change Order were not anticipated during
specification development. Therefore, it is the recommendation of the City Manager that the
City Council adopt Alternative No. 1 as stated above.
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