Zoning Amendment Carlson Z AP 8234 Carlson under separate cover Development Permit/Specific Use PSCo DP AP 8237 PSCo

Transcription

1 FILED ELECTRONICALLY May 3, 2017 Ms. Lori Hight, AICP Senior Planner City Development 9500 Civic Center Drive Thornton, CO Re: Response to Comments on the Second Review of the Land Development Approvals Application Submittal for the Thornton Electric Substation Project and Carlson Land, Inc. Retail Development Sites Dear Ms. Hight: Public Service Company of Colorado (PSCo), a Colorado corporation doing business as Xcel Energy, and Carlson Land, Inc. (Carlson) are proposing to develop approximately 11.6 acres of land located at the southeastern corner of East 120 th Avenue and Holly Street in the (City). Details regarding the proposed development were provided in the permit application for a Conceptual Site Plan (CSP) that PSCo and Carlson submitted jointly in October 2016 as well as other submitted documents as outlined in Table 1: Table 1: Summary of Submittals to the Submittal Type (a) Original Submitting Entity Identifier Responding Entity Conceptual Site Plan (CSP) Joint applicants: Carlson and CSP AP 8232 PSCo and Carlson PSCo Snydal Annexation Agreement Carlson ZAX AP 8233 (b) Carlson under separate cover Amendment Application Zoning Amendment Carlson Z AP 8234 Carlson under separate cover Development Permit/Specific Use PSCo DP AP 8237 PSCo Permit (DP/SUP) Height Variance for Static Masts PSCo V AP 8240 (c) PSCo Comprehensive Plan Amendment (CPA) PSCo SPCD AP 8235 PSCo a The submitted documents and City referral comments are available online at this location: b A letter dated March 24, 2017, from PSCo and Carlson to the City requested that the height variance request for the static masts be included in the Annexation Agreement Amendment. c The previous variance request dated October 27, 2016, was withdrawn by letter from PSCo and Carlson on March 24, 2017.

2 Page 2 of 6 The City completed an initial review of the submitted materials and provided referral comments to PSCo and Carlson in a letter dated December 12, 2016, and through additional meetings and communication that occurred January through March PSCo and Carlson submitted responses to the initial review comments along with revised drawings and studies to the City on March 24, 2017 (Submittal Number 2). The City provided comments on Submittal Number 2 in a letter from Lori Hight, Senior Planner, dated April 17, PSCo and Carlson met with the City on April 19, 2017 to review the comments and discuss the planned responses. Comments from Development Engineering were received on April 21, 2017, and on April 26, 2017, and additional questions regarding Electric and Magnetic Fields (EMF) analysis were received on April 27, The remaining sections of this letter address each referral comment provided on Submittal Number 2. Each comment has been duplicated and a response has been provided to each along with references to exhibits provided in support of this submittal. Exhibits that have been included as attachments to this letter and referenced in the responses to comments below are listed in Table 2. Table 2: Summary of Exhibits Attached to Letter Exhibit No. Exhibit Title Description 1 Responses to Comments on CPA Red-lined Drawings Red-lined drawings from the CPA (plans) with responses provided in blue boxes with blue text 2 Responses to Comments on DP/SUP Red-lined Drawings Red-lined drawings (plans) with responses provided in blue boxes with blue text 3 Responses to Comments on Drainage Report Red-lined Drainage Report with responses provided in blue boxes with blue text 4 Revised CPA Drawings Revised drawings (plans) 5 Revised DP/SUP Drawings Revised drawings (plans) 6 Revised Drainage Report Revised drainage report, including revised drawings 7 EMF Analysis Graphic showing magnetic field contours 8 Neighborhood Meeting Summary Summary of the neighborhood meeting held on April 27, 2017 Referral Comments Letter dated April 17, 2017 Current Planning Senior Planner, Lori Hight Planning Comment 1: See the attached red-lined drawings for comments from Current Planning. Response: Exhibit 1 provides responses to comments on the CPA drawings and Exhibit 2 provides responses to comments on the DP/SUP drawings. Please reference the following files to review the comments and responses specific to Current Planning: Exhibit1_2_Planning_comment_2_Comp_Plan_Amend.pdf Exhibit2_2_Planning_comments_2_DP.pdf

3 Page 3 of 6 The CPA and DP/SUP drawing sets have also been updated as a result of the cumulative comments from the City. Exhibit 4 contains the updated CPA drawing set and Exhibit 5 contains the updated DP/SUP drawing set. Planning Comment 2: Please be aware that a Subdivision Plat is required prior to the issuance of any building permits for this property. A subdivision plat and developer s agreement (DA) as well as civil construction drawings must be approved and the plat and DA recorded prior to the issuance of building permits. This process often takes a long time. Response: Comment noted. Development Engineering Civil Engineer, Nate Hatleback Development Engineering Comment 1: Comments from Civil Engineer will be forthcoming as soon as possible. Response: Development Engineering comments were provided on April 17, 2017, and April 21, Exhibit 2 provides responses to comments on the DP/SUP drawings and Exhibit 3 provides responses to comments on the Drainage Report. Please reference the following files to review the comments and responses specific to Development Engineering: Exhibit2_DE_Redlines-2_Revised_DP-SUP_Drawings.pdf Exhibit3_DE_Redlines-2_Final_Drainage_Report.pdf Exhibit 5 contains the updated DP/SUP drawing set and Exhibit 6 contains the updated Drainage Report (including drawings) that has been revised per the comments received. Development Engineering Comment 2: See the attached red-lined drawings for comments from the Traffic Engineer. Response: Traffic Engineering did not provide comments on either the CPA or DP/SUP. Responses to comments provided by Traffic Engineering on the CSP, Annexation Amendment, and Traffic Impact Study will be submitted directly to the City on May 3, 2017, under separate cover by Kimley-Horn on behalf of Carlson. Landscape Architect Senior Landscape Architect, Heidi Feigal Landscape Architect Comment 1: See the attached red-lined drawings for comments from the Landscape Architect. Response: Exhibit 2 provides responses to comments on the DP/SUP drawings. Please reference the following file to review the comments and responses specific to the Landscape Architect: Exhibit2_2_LA_comments_2_DP.pdf Exhibit 5 contains the updated DP/SUP drawing set that has been revised per the cumulative comments received.

4 Page 4 of 6 Infrastructure Engineering Senior Surveyor, Bryan Zimmerman Infrastructure Engineering Comment 1: See the attached red-lined drawings for comments from the City Surveyor. Response: Infrastructure Engineering did not provide comments on either the CPA or DP/SUP. Responses to comments provided by Infrastructure Engineering on the Zoning Amendment will be submitted directly to the City on May 3, 2017, under separate cover by Kimley-Horn on behalf of Carlson. Additional Comments from Lori Hight, April 27, 2017 Comment Regarding EMF We would like to repeat and clarify our request for an EMF study. With respect to your response of March 27, 2017, concerning the request for a site specific EMF study to assist staff in our recommendation for the Specific Use Permit, staff understands that the CPUC has determined that expected magnetic field values for the overhead and underground transmission lines and the substation meet the conditions of the Commission Rules. We note, however, that the only information presented in PSCo s application for the CPCN with regard to magnetic fields was the two exhibits illustrating the analysis results for expected magnetic field values associated with the overhead and underground transmission lines (Attachments BDC-4 Final OH Transmission EMF and BDC-5 Final UG Transmission EMF). Staff requests that PSCo provide similar information showing the modeling and analysis performed to determine the magnetic field strength of less than one (1) milligauss (mg) at a location one meter above ground at the substation boundary, as described in the Development Permit and Specific Use Permit Application on page 43 (excerpt follows): Electric and Magnetic Fields The PUC has deemed the EMF levels for the proposed project are reasonable by rule. PSCo has modeled EMF characteristics of the Thornton Electric Substation at full build-out (three 50MVA transformers). The EMF characteristics associated with the electrical current passing through the equipment in the substation and in the underground transmission lines that provide power to the substation will decrease rapidly with distance and are expected to be less than 1milliGauss (mg) along the eastern property line. The modeling shows that the substation will produce no measurable magnetic fields on private properties adjacent to the proposed facility. These modeling results are consistent with actual field measurements taken at existing substations with similar design characteristics. Any EMF detected inside residences at the adjacent private properties will be derived solely from electrical systems and equipment that use electricity located inside the residences. On the southern property line along the northern side of East 119th Avenue, the fields will be elevated within the right-of-way of the underground electric transmission line beneath East 119th Avenue and where the underground transmission line turns and crosses under the sidewalk to enter the substation. In addition to providing the results of this modeling and its conclusions to the public, PSCo provided additional educational information regarding EMF on the project website. This information can be found at Response: An analysis of the potential impact of magnetic fields from the new transformers and buss conductors was completed at a location one meter above ground at the substation boundary. A 3D magnetic field modeling analysis was conducted for the ultimate three-transformer buildout configuration of the substation to estimate the levels of magnetic fields at the substation boundary.

5 Page 5 of 6 All electric utility wires and devices that carry electrical current generate magnetic fields. The earth itself generates steady-state magnetic fields. Magnetic fields are produced by the electrical load, or the amount of current flow, through the conductors measured in terms of amperage. The magnetic field strength is directly proportional to the amperage; that is, increased power flow results in increased amperage that produces a stronger magnetic field. The magnetic field is inversely proportional to the distance from the conductors and the strength declines as the distance from the conductor increases. Magnetic fields are expressed in units of milligauss (mg). However, unlike voltage, the amperage, and therefore the magnetic field around electric utility wires and devices, fluctuates hourly and daily as the amount of current flow varies. In a complex facility such as an electrical substation, the strength of the magnetic field at any point depends on the current flowing in nearby conductors, the geometry of the construction of the substation, the degree of reinforcement or cancelation from other conductors of similar or different electrical phases, and the distance from the conductors or cables. Analysis The magnetic field analysis was conducted using the 3D-FIELDS program. The 3D-FIELDS program, written by the Southern California Edison Company, is designed to calculate and plot in three dimensions the magnetic fields produced by any wiring configuration such as those used in substations and other similar electrical facilities. The magnetic fields that will be generated by the proposed substation were calculated using the Grid mode in 3D-FIELDS at an elevation of 3 feet above ground. The accuracy of the modeling is dependent on the accuracy of the input data (i.e., if the average phase current is higher than what was modeled, so will the resulting magnetic fields). The resulting field plots are within a small percentage of the true value for the conditions modeled. The 3D magnetic field analysis was conducted with the following assumptions. The underground transmission line bringing power to the substation was assumed to carry 250 megavolt amperes (MVA) of power. This line connects to a riser structure where the current is conducted up and onto the overhead buss. The power flows in the circular buss to the transformers where 50MVA is pulled off at each of the three transformers. The remaining 100MVA of power flows back out of the substation on the second underground transmission line back to the overhead transmission line. The currents in the buss conductors within the substation were calculated to depict the magnetic fields that would be produced by the substation operating in its ultimate buildout configuration and at maximum current flows. The transformers, circuit breakers, and other items of discrete electrical equipment within the substation were not modeled since they comprise point sources of magnetic fields that will have a very rapid cube of the distance decay of their magnetic fields. For example, if a magnetic field of 100mG is predicted at 5 feet from a transformer the field level becomes approximately one-eighth of this or 12.5mG at twice the distance (10 feet) and 1.6mG at 20 feet. Therefore at the distance to the substation wall, the field levels will have dropped to background levels. The gridded magnetic field values from the buss conductors computed by 3D-FIELDS were then plotted using the 3D graphing program Surfer, which is available from Golden Software. Surfer creates a threedimensional surface view of the magnetic field levels across the substation.

6 Page 6 of 6 The magnetic fields that will be generated by the proposed substation were plotted as shown in Exhibit 7. The higher magnetic fields shown in the purple and pink colors are the locations where the magnetic field is the highest. The lowest levels down to 50mG are shown in dark green and levels below 50mG are shown as grey. Conclusion The exhibit shows that the magnetic field strength decreases to background levels at the new substation walls on all sides. In other words, all magnetic fields from the substation busses and conductors will decay to zero inside the wall. Outside the wall, the magnetic fields from the substation will be zero as well. The substation fields will also be zero at the nearest houses to the east of the substation. This magnetic field analysis was managed and report prepared by Robert Pearson, Ph.D., PE. He is a senior project manager at Tetra Tech in their downtown Denver office and is a registered professional engineer in Colorado. Dr. Pearson has 45 years of experience with EMF and has authored many articles and reports on the subject. In addition, Dr. Pearson has qualified to testify as an EMF expert both in court proceedings and in numerous administrative and rulemaking proceedings. This concludes PSCo s response to comments on the second review of the land development approvals application submittal for the Thornton Electric Substation Project and Carlson Land, Inc. retail development sites. In addition to the comment responses and revised materials being provided as a part of this submittal, a summary of the Neighborhood Meeting held on April 27, 2017, has also been provided as Exhibit 8. We look forward to working with you during the ongoing permit review process. Please do not hesitate to contact us if we can assist with any information or questions. Susan Innis (PSCo) can be reached at and Cory Thornton (Carlson) can be reached at Sincerely, Susan Innis PSCo Manager, Siting and Land Rights susan.a.innis@xcelenergy.com Sincerely, Cory Thornton Carlson Land, Inc. Broker cory@carlsonland.net