2020-086 Hickory SubstationDate: October 9, 2020 Report No. 2020-086
INFORMAL STAFF REPORT
TO MAYOR AND CITY COUNCIL
SUBJECT
Provide background and historic references to City Council decision to move from Air Insulated
Substation (AIS) to Gas Insulated Substation (GIS) construction and associated façade for the
proposed Hickory Substation located east of Bonnie Brae St, between Oak St. and Hickory St.
EXECUTIVE SUMMARY:
Beginning in 2014 DME has provided Council presentations, for which guidance was requested,
as to their direction for construction of the future Hickory substation and its façade. This report
is a collection of the historic milestones related to the Hickory Substation GIS and its facade/wall.
DISCUSSION:
On December 2, 2014, a City Council Work Session report (ID 14-0764), directed DME to enlist
input from citizens through the creation of an Aesthetics Committee to discuss the appearance of
the façade for Hickory Substation. Direction given at this meeting established an Aesthetic
Committee to look at options for Hickory Substation’s façade.
(Time unknown) As result of citizen comment, the idea of a gas insulated substation was
introduced into the deliberations.
At the City Council meeting on November 17, 2015, DME provided (ID15-10371) Council a
presentation, and requested guidance, regarding the potential utilization of GIS technology for
DME electric substations. The substation of topic was the proposed Eagle Substation. The
presentation included information on AIS/GIS cost differences, personnel requirements,
footprints, performance/reliability, operations/maintenance, as well as photo simulations2 for AIS
vs. GIS.
On June 21, 2016, the City Council (ID 16-7113) was requested to provide DME staff direction
regarding the Hickory Substation site related to options to the station’s configuration and aesthetic
treatment. The presentation included background information on the Hickory Substation site,
displayed the recommendation of the Aesthetic Committee, and estimated construction costs. It
was during this Council meeting that DME was given direction to build the new Hickory
Substation with GIS technology as well as the Council’s preference for a façade/wall which is
shown in the image below.
1 City of Denton Meeting Agenda – City Council, November 17, 2015
2 City of Denton Council Minutes, November 17, 2015
3 City of Denton Meeting Agenda – City Council, June 21, 2016
Date: October 9, 2020 Report No. 2020-086
Additional direction from this Council meeting included DME to move forward with underground
transmission circuits appropriate to the construction of this substation as well as converting
existing overhead distribution circuits, in the same general area, to underground.
On July 18, 2017, Council approved (ID 17-8644/Consent Agenda) a Professional Services
Agreement for Architectural and Design Services relating to the Hickory Substation Gas Insulated
Substation Equipment Building and Screening Wall.
When deliberations for both the Eagle and Hickory Substations were initiated, the plan was to have
both substations equipped with two (2) transformers in each substation to provide a combined
service capacity of 100 MW. With the August 18, 2020 direction from the Council to not build
Eagle Substation, the design of the Hickory GIS was adjusted to compensate for the additional
load serving capacity originally planned for a Hickory & Eagle Substation scenario. DME’s
current plans for Hickory Substation is for it to be equipped with four (4) transformers which
provides the same 100 MW capacity. Only two (2) transformers will be installed initially with the
others installed as demand grows and they are justified. However, please know the footprint for
Hickory Substation GIS will not change; plus, no changes are currently anticipated for the planned
façade. All needed adjustments will be inside the façade.
The current timeline for the design and construction of Hickory Substation is to complete its
technical specifications, on or before, March 2021; issue an RFP, on or before, May 2021; and
request Council approval of the design/build contract, on or before, December 2021. Hickory
Substation is currently scheduled to be on-line, on or before, the summer of 2023. Please know
these dates are subject to change based on conditions or other factors that may be out of the control
of DME.
4 City of Denton Meeting Agenda – City Council, July 18, 2017
Date: October 9, 2020 Report No. 2020-086
The original cost estimate for the Hickory Substation was $25 million and current cost estimate
for the Hickory Substation and associated costs is now $32.5 million. While this represents an
increase from the initial budget, the combined cost estimate for the Hickory Substation and the
Council approved Eagle Substation was $51.2 million. Elimination of the Eagle Substation
coupled with changes that DME Engineering Division has recommended to the distribution
system, the net capital cost savings is now estimated to be $18.6 million with increased reliability
as compared to the prior two new substation plan and no change to the overall timing of planned
future substations.
CONCLUSION:
DME has no plans to solicit additional input from the community and is moving forward with
Council’s direction related to Hickory Substation construction as a GIS, its façade, and
undergrounding of both transmission and distribution assets in the general area of the proposed
substation.
STAFF CONTACT:
Jerry Fielder, P.E; Division Engineering Manager; 940-349-7173