CITY COUNCIL AGENDA ITEM
ACTION REQUESTED:
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Consider the request for approval of a conditional use for a data center, variances for parking and equipment screening wall height, and an Owner’s Acknowledgement and Acceptance Agreement for the property located at 1960 Lucent Lane (Karis Critical Data Center) - DEV-0057-2025
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DEPARTMENT: Transportation, Engineering and Development
SUBMITTED BY: Sara Kopinski, AICP
BOARD/COMMISSION REVIEW:
The Planning and Zoning Commission (PZC) considered the Petitioner’s request on the following dates: August 20, 2025; September 3, 2025; October 15, 2025; November 5, 2025; and November 19, 2025. On November 19, 2025, the PZC voted to recommend approval of the Petitioner’s request (approved 8-1).
BACKGROUND:
The subject property consists of approximately 20 acres of a larger parcel of approximately 41 acres of vacant land located at 1960 Lucent Lane. It is currently zoned ORI (Office, Research and Light Industry District) and is located along the City’s I-88/Diehl Road corridor. The I-88/Diehl Road corridor is largely developed with buildings used for office or institutional purposes though there are three residential neighborhoods in the area (Naper Commons, Danada Woods, and unincorporated Indian Hill Woods). If development of the subject property proceeds, it will be assigned an address of 1936 Lucent Lane.
Karis Critical Member, LLC proposes development of an approximately 211,160 square foot data center on the subject property that will be used for computer systems and associated components that process and distribute large amounts of data. While there will be only one data center, it may be constructed in phases, with Phase 1 consisting of approximately 145,000 square feet and, full buildout with Phase 2, occurring in the future as depicted in the attached plans. To develop the subject property with a data center the Petitioner requests approval of:
1. A conditional use pursuant to Section 6-8B-3 of the Code to allow the operation of one data center in the ORI zoning district;
2. A variance from Section 6-9-3 of the Code to reduce the required parking for the data center from 211 spaces to 60 spaces;
3. A variance from Section 6-2-12:3 of the Code to increase the maximum permitted height of the proposed equipment yard screen wall from 15 feet to 22 feet.
DISCUSSION:
Public Hearing Summary
The public hearing for the Karis Critical Data Center spanned several PZC meetings and a significant amount of public testimony was received during this timeframe:
1. The PZC opened the public hearing for the data center August 20, 2025, and continued the hearing to September 3, 2025, at the Petitioner’s request.
2. On September 3, 2025, the PZC reconvened the public hearing, began Petitioner and public testimony, and continued the public hearing to October 15, 2025.
Prior to October 15, 2025, the City hired Hampton, Lenzini and Renwick, Inc. (“HLR”), a third-party sound engineer, to review the Petitioner’s Noise Impact Assessment, verify the data center campus will operate in compliance with City regulations identified in Section 6-14-4:1 of the Municipal Code, and determine if any additional improvements are recommended to mitigate potential noise impacts.
3. On October 15, 2025, the PZC reconvened the public hearing, resumed Petitioner and public testimony, and continued the hearing to November 5, 2025.
4. On November 5, 2025, the PZC reconvened the public hearing, completed public testimony, began the Petitioner’s closing remarks, and continued the public hearing to November 19, 2025, to resume the Petitioner’s closing remarks and PZC deliberation
5. On November 19, 2025, the PZC reconvened the public hearing, granted Petitioner’s request to reopen the Petitioner’s Presentation and the Public Comment and Testimony components of the public hearing solely for the limited purpose of receiving additional testimony or evidence, including cross-examination, related to the regulatory framework and air permitting associated with emissions at the proposed Karis Critical Data Center, and resumed Petitioner’s closing remarks.
At the conclusion of the public hearing on November 19, 2025, the PZC deliberated and then voted to adopt Petitioner’s proposed findings pertaining to the requested conditional use and variances and recommended approval of the Petitioner’s requests (approved 8-1). Additional information on PZC’s review can be found below.
Key Development Considerations
Primary topics discussed during the public hearing included, but were not limited to:
• Prior ORI Amendments: In 2023, the City Council passed Ordinance No. 23-091 amending the ORI District’s zoning regulations in the Naperville Municipal Code (“Code”). Amongst other changes, the 2023 ORI Amendment classified data centers as a conditional use in the ORI district and established “Required Conditions” for conditional and permitted uses in the ORI district.
The Required Conditions provided in Section 6-8B-4 (ORI/Required Conditions) of the Naperville Municipal Code include review of the following components: property location; anticipated truck and customer traffic and parking generation; current and proposed roadway capacities; site access; visibility of the property from major thoroughfares; proposed building design; and other criteria determined to be necessary. Conditions that could be imposed to mitigate potential adverse impacts of proposed conditional uses may include: additional landscaping; improved building elevations and/or materials; access restrictions or additional access; directional signage; increased setbacks; improved lighting; and/or change in building orientation.
• Noise: Noise associated with data center operations was a concern consistently raised by residents in the general vicinity of the project. To ensure noise associated with operation of the data center campus does not impact nearby residents, the Petitioner submitted a Noise Impact Assessment.
While the initial Noise Impact Assessment confirmed that the data center’s noise contributions comply with Naperville Municipal Code requirements, the City hired Hampton, Lenzini and Renwick, Inc. (“HLR”), a third-party sound engineer, to review the Petitioner’s Noise Impact Assessment, verify the data center campus will operate in compliance with City regulations identified in Section 6-14-4:1 of the Municipal Code, and determine if any additional improvements are recommended to mitigate potential noise impacts.
HLR confirmed that the Petitioner’s Noise Impact Assessment complies with the requirements of Naperville Municipal Code Section 6-14-4:1, which sets the Naperville noise standards. While not required by the City’s ordinance, as a best practice in data center development, HLR recommended that the Petitioner’s sound engineer, Jacob and Heffner, compare the proposed noise levels to the Illinois Pollution Control Board (PCB) Standards to ensure that none of the nine octave bands are exceeded, at the closest residential receptor, R1-1. The octave bands address the groups of frequencies that quantify how humans distinguish sound (i.e. a low hum vs. high, airy sounds).
The Petitioner was responsive to this request and conducted additional noise studies relative to compliance with more restrictive PCB Standards. The Noise Impact Assessment dated December 2, 2025, provided by Petitioner’s consultant, Jacob Hefner & Associates, showed that the anticipated total noise contributions from the proposed data center development would remain below both the City’s noise regulations and PCB limits. Additionally, the Assessment concluded that noise levels anticipated to be produced by the facility would be below the pre-existing background noise measured surrounding the subject property.
• Generators/Diesel emissions: The Petitioner proposes a total of 24 emergency generators to be located in the equipment yard, in the rear of the data center building. Petitioner has confirmed that 3MW diesel generators that meet U.S. EPA Tier 4 emission standards will be used, and that they will be part of a containerized system that will ensure sound attenuation and integral fuel containment. A 22-foot screen wall is proposed around the equipment yard, to further mitigate potential visual or audible issues surrounding the operation of generators.
The Petitioner has specified that generators will be used solely in the event of a power outage or for periodic testing to ensure their operation - they will not be used for peak shaving or any other purpose.
• Water considerations: The proposed data center will use a closed loop cooling system which is considered a highly efficient method that uses a contained liquid to absorb and remove heat directly from IT equipment. Unlike traditional air-cooling, which moves heated air out of the building, a closed-loop system recirculates the same liquid within a sealed environment. This approach is more effective, energy-efficient, and reduces water consumption because it doesn't rely on evaporation to dissipate heat.
The primary advantage of this system is that the liquid never comes into contact with outside air, minimizing evaporation and contamination. The same fluid is used over and over, requiring only a small amount of "makeup" water to account for minor leaks.
This type of system should not create a large water consumption demand nor will it place undue pressure on the existing water supply and distribution systems. Furthermore, the City’s Water Utilities Department confirmed that the proposed data center will utilize substantially less water per day than prior buildings on the property.
• Electric considerations: Data center development often requires significant upgrades to electric utility infrastructure to support their energy needs. As of December 17, 2025: (i) the City has confirmed with ComEd that there is sufficient electrical capacity available to the City of Naperville to power the data center up to a maximum amount of 36 MW of Peak Electric Load; and (ii) subject to data center funded system improvements, the City has the ability to power the data center up to a maximum amount of 36 MW of Peak Electric Load. However, the City will not reserve capacity for the data center until a site permit has been obtained from the City to construct the data center. Further, the availability of electrical capacity to the City of Naperville to serve the data center is subject to the availability of electricity to the City from ComEd.
The availability of electrical capacity to the City of Naperville to serve the data center is subject to the availability of electricity to the City from ComEd. Electrical capacity for the data center was approved by ComEd in the amount of 36 MW of Peak Electric Load in an email dated September 12, 2025, and reiterated in a letter dated December 17, 2025. All fees are required to be paid prior to start of construction. The capacity to provide the data center with electricity, and in a manner that will not impact other rate payers, is the subject of Section 6 of the proposed Owner’s Acknowledgement and Acceptance Agreement discussed later in this memo.
Availability of sufficient power for other development within the City is an issue that should be considered and planned for in considering whether to approve the data center. The capacity of both the ComEd and Naperville electric systems is not unlimited. If approved, the data center will be the City largest electrical customer and may have an impact on the timely availability of energy for future development in the I-88 Corridor. In analyzing the additional 36MW of capacity needed for the Electric Utility to provide energy to the data center, the City provided both its consultant and ComEd with projected load growth through 2030 and the conclusion was that there is sufficient capacity available to handle reasonable growth over that time. It is, however, unlikely that the City would be able to accommodate another large load customer without significant improvements which will involve both substantial time and costs relative to the ComEd and Naperville systems.
One concept discussed at the August 19, 2025, City Council meeting was the inclusion, in negotiations with the Illinois Municipal Electric Agency (IMEA), of an option for the City to increase its permissible member-directed resources (MDR) in proportion to any increased energy load resulting from the addition of significant energy-usage customers, such as data centers. MDR is not currently authorized under the city’s current power sales agreement with IMEA. The City Council has indicated that it would like to see additional MDR options in a successor agreement.
• Safety considerations: During the public hearing, some individuals expressed concerns with the fuel storage tanks required by data centers and spill mitigation plans. The City’s Fire Department confirmed that the Office of the State Fire Marshal regulates fuel storage tanks. As is standard practice, the developer will be required to obtain permits through the City as well as through the State Fire Marshal, and the proposed data center will be required to have an Emergency Plan which will include any spill mitigation. Operators on the site will also be required to provide an annual report to the City to identify what chemicals, and in what amount, they have on site.
The Fire Department does not have any concerns with future fire protection on the property. The data center will be required to be fully sprinklered along with an automatic fire alarm. Fire protection equipment will need to be installed per the National Fire Protection Association (NFPA) 13. Battery storage and computer storage areas are expected to have special extinguishment systems but will also be backed up by sprinkler systems.
• DuPage County Forest Preserve impacts: The development plans for the proposed data center campus have been shared with the Forest Preserve District of DuPage County (FPDDC) for their review and comment. The FPDDC has provided a written response to the Petitioner’s proposal, outlining recommendations for the photometric plan to adopt recommendations as set forth by the International Dark Sky Association and Dark Sky Society, as well as refrain from using asphalt sealants that contain coal tar products to minimize threats to plants and wildlife. The Petitioner has agreed to comply with both requests.
Project Development
Multiple modifications were made to the Karis Critical Data Center proposal in response to the comments and feedback provided during the public hearing process. As modifications were proposed, the Petitioner submitted revised plans and supplementary materials for review. Key modifications made during the public hearing include:
• Elimination of one data center building: The Petitioner’s original proposal included two data centers and a private electrical substation on approximately 41 acres. Following the September 3, 2025, PZC meeting, the Petitioner eliminated the eastern data center building (the building closest to Naper Commons) and associated utility substation. This modification also resulted in the elimination of a variance request to permit an increase in the height of the security fence for the private electrical substation to a maximum of 8 feet. Further, this reduced the scope of the requested conditional use to just the western 20 acres of property which were the subject of the original Petition.
• Stewardship Pledge: At the October 15, 2025, PZC meeting, the Petitioner presented a proposed Stewardship Pledge to reflect the best practices and site-specific stewardship initiatives that have been incorporated into the proposed data center project. The Stewardship Pledge highlights the Petitioner’s continued commitments to Naperville and the surrounding community. The Stewardship Pledge has been incorporated into the Owner’s Acknowledgement and Acceptance Agreement attached to this agenda item.
• Elimination of Weatherbee Lane access point: When the second data center building was removed from Petitioner’s proposal, the site access point that was originally proposed on Weatherbee Lane was eliminated. As a result, all traffic will be required to enter and exit the site from Lucent Lane.
• Additional Noise Study: In response to recommendations from the city’s third-party noise consultant, the Petitioner conducted an additional noise study, the Noise Impact Assessment dated December 2, 2025, submitted by Petitioner’s consultant, Jacob Hefner & Associates, to confirm that it is anticipated that noise contributions from the data center will comply with both the City’s requirements as outlined in Section 6-14-4:1 of the Municipal Code as well as with Illinois Pollution Control Board (PCB) Standards to ensure that none of the nine octave bands are exceeded, at the closest residential receptor.
• Building elevations: The building elevations were enhanced to include additional accent materials and to raise the parapet walls to the full height of the rooftop mechanical units.
• Site lighting: The Petitioner has provided a letter confirming that all exterior light fixtures proposed on the subject property are “Dark Sky” compliant and an updated photometric plan which includes a note stating that all light fixtures are “dark sky” compliant. The OAA also includes Dark Sky provisions.
• Plan modifications: Other plans and documents were updated as necessary to reflect these proposed modifications.
Public Testimony at the PZC Public Hearing
As a result of high levels of public participation at the PZC public hearing regarding the proposed data center, there were four dates at which public testimony was taken on the data center petition. Members of the public shared concerns regarding potential health impacts associated with the use of backup generators and diesel emissions from the data center. Noise impacts from backup generators and cooling systems were also a subject of significant concern, especially in light of problems recently encountered when repairs were required for an Aurora data center resulting in the need to use backup generators for a significant period of time which caused a major impact to residents due to noise. A negative impact on property values was also expressed as a concern. Finally, concerns were raised regarding the possibility of higher electric rates resulting from the data center’s demand on the resources of the City’s electric system.
Planning and Zoning Commission Action
At the conclusion of Petitioner’s closing remarks on November 19, the PZC began their deliberation and discussed IEPA inspections, I-88 noise and pollution, generator and chiller equipment operation, fuel deliveries, use of natural gas, noise, comparisons to other data centers in Naperville, the future of the Nokia building, future development on the subject property, efforts for ongoing communication with nearby residents, and the Petitioner’s proposed Stewardship Agreement.
The Commission generally supported the requested entitlements and found that an appropriate level of scrutiny has been applied in consideration of nearby residential properties and that the evidence provided demonstrates that the data center can operate without creating adverse impacts that are incompatible with surrounding property. The Commission also noted that this level of scrutiny resulted in meaningful plan changes (detailed in the preceding Project Development section of this report).
Following deliberation, the PZC closed the public hearing and voted to recommend approval of the Petitioner’s request subject to the conditions outlined in the staff report (8-1). Commissioner Naumes cast a dissenting vote finding that the proposed data center would introduce adverse impacts to neighboring residential properties, including noise and resource consumption, that are out of character with the surrounding area. Commissioner Naumes also indicated the Stewardship Pledge did not provide the framework necessary for mitigating resource consumption, noise, or health related impacts.
ZONING REQUESTS:
Conditional Use
Pursuant to Section 6-8B-3 (ORI/Conditional Uses) of the Naperville Municipal Code, the Petitioner requests approval of a conditional use for one data center in the ORI zoning district. The proposed site improvements comply with the required setbacks and bulk regulations set forth in the ORI district. During staff’s review of the proposed data center campus, consideration was given to ensure the proposed development can be adequately served by public facilities and services (including streets, public utilities, stormwater and drainage facilities, etc.) and to the various design components.
Findings of Fact
The Petitioner’s responses to the Standards for Granting a Conditional Use can be found in the attachment titled “Response to Standards.”
Parking Variance
The Petitioner requests approval of a parking variance from Section 6-9-3 of the Code to reduce the required parking for a data center from 211 parking spaces to 60 parking spaces. To support the requested variance, the Petitioner has submitted a parking evaluation that outlines employment shifts and employee counts. The data center will have approximately 40 to 45 employees working the first shift, six to ten employees working the second shift, and six to ten employees working the third shift. The maximum number of employees to be working at each of the data center buildings is estimated to be 40 to 45 people and will occur during the first shift.
Providing 60 parking spaces is expected to be sufficient for data center operations. However, in the unexpected event that the parking provided is not sufficient, the Petitioner will reserve a land banked area that will be required to be constructed in the event that additional parking is required based on actual use of the property.
Equipment Yard Screen Wall Variance
The Petitioner requests approval of a variance from Section 6-2-12.3 of the Code to increase the height of the equipment yard screen wall from 15 feet to a maximum of 22 feet to mitigate sound emitted from the equipment yards and screen the equipment within the yards from surrounding properties and rights-of-way. The Code limits walls enclosing outdoor storage areas to a maximum of fifteen feet in height to help ensure compatibility with adjacent land uses and to maintain massing that is appropriate for neighboring properties.
The Petitioner’s proposed site plan includes an equipment yard in the rear of the data center building. The proposed screen wall was designed to be an integrated component of the overall building design, using building materials, colors, and a height that fully screens mechanical equipment to its full height. The screen walls are anticipated to provide necessary visual and noise mitigation measures for the benefit of surrounding properties.
Findings of Fact
The Petitioner’s responses to the Standards for Granting a Variance can be found in the attachments for each variance requested.
SUMMARY OF THE OWNER’S ACKNOWLEDGEMENT AND ACCEPTANCE AGREEMENT FOR THE KARIS CRITICAL DATA CENTER (OAA)
The Petitioner, Karis Critical Member, LLC, is the contract purchaser of the subject property. The proposed conditional use ordinance allows Petitioner up to 120 days to execute the OAA, after it has finalized purchase of the data center property. Once signed, the OAA will be a binding contract between the City of Naperville and Karis Critical Member, LLC. The OAA establishes comprehensive conditions for the construction, operation, and ongoing compliance of the Karis Critical Data Center. It incorporates the recitals, approved plans, and exhibits, and ensures adherence to applicable laws, codes, and prior entitlements. Key provisions include:
1. Development and Compliance Requirements:
a. Karis must comply with the Naperville Municipal Code, all relevant ordinances (including the Nokia Ordinances and OAA), the Nokia Declaration, and state/federal laws.
b. Construction of on-site and off-site improvements, including electrical upgrades, is at the Karis’ sole cost.
c. Changes to approved plans require City approval per Municipal Code Section 6-3-8.
d. Equipment selection must be verified through a process comparing projected and selected facilities, including noise impact assessments, with a 60-day verification period post-temporary occupancy to confirm compliance with noise, electricity, water, and vibration standards. Non-compliance may result in permit revocation or extensions for corrections.
e. Modifications to equipment or facilities require City approval, potentially involving a City consultant at Karis’ expense.
2. Electricity Supply and Sustainability:
a. The data center must purchase 100% of its electricity from the City, capped at a peak electric load of 36 MW, subject to ComEd availability.
b. Karis prepays all costs for City electrical infrastructure improvements, including those to the Indian Hill Substation.
c. Annual true-up reports ensure no subsidies between the data center and other City customers, with Karis reimbursing the City for any additional procurement costs for capacity, energy, and ancillary services.
d. Enrollment in the City's Green Energy Certificate Program requires purchasing Renewable Energy Certificates (RECs) to match 100% of the peak load to renewable sources, initially from Illinois or M-RETS region projects, with future commitments determined collaboratively.
3. Cooling and Water Usage:
a. An air-cooled closed-loop system with up to 24 rooftop HVAC units is required, designed for zero daily water consumption beyond initial fill and maintenance.
b. System maintenance is mandatory, and replacements require City approval, ensuring no significant increase in noise, water use, or violations of codes/laws.
4. Noise and Vibration Mitigation:
a. Operations must comply with Illinois Pollution Control Board standards, Illinois Administrative Code, and City noise performance standards, based on the attached Noise Impact Assessment.
b. Up to 24 Tier 4 diesel backup generators (not exceeding 3 MW each) are permitted in an enclosed yard with a 22-foot screen wall.
c. Generator testing is limited to weekdays (9 a.m.-5 p.m., no holidays), no more than two concurrently, and not exceeding 10 hours annually total. Non-emergency use is restricted during poor air quality (AQI above 50) and requires coordination with the City.
d. Emergency use is limited to power outages or safety threats, with prompt return to utility power.
e. Vibrations must comply with Naperville Municipal Code regulations (Section 6-14-4:4).
f. Post-occupancy noise studies may be required if exceedances are suspected, with prompt remediation at Karis’ expense.
5. Environmental and Safety Measures:
a. Rooftop equipment screening complies with Naperville Municipal Code regulations (Section 5-10-3:12), with potential modifications for sound attenuation.
b. No coal tar products are permitted.
c. An E-Waste Management Plan must be submitted pre-occupancy and maintained.
d. Battery systems for bridging power must meet 2024 International Fire Code standards, coordinated with the Fire Department.
e. An Emergency Response and Safety Plan is required pre-occupancy.
f. Lighting complies with City standards and Dark Sky principles.
6. Parking and Site Features:
a. 60 parking spaces are approved, with 114 land-banked spaces reservable for future construction if needed, per Zoning Administrator determination.
b. Additional loading docks or site/landscape/elevation changes require City review.
7. Reporting and Community Engagement:
a. Initial documentation includes Air Permit applications and issuance.
b. Annual Reports for the first five years (and as requested thereafter) detail electricity/water usage, generator operations, fiscal impacts, violations, and compliance affirmations.
c. A public website and community email for concerns must be maintained, with notifications for extended generator use (>4 hours).
d. Designated contacts for 24/7 communication are required.
8. Other Provisions:
a. No cryptocurrency or bitcoin mining is allowed.
b. If the data center ceases operations for two years, a decommissioning plan for generators and hazardous materials is required.
c. Karis’ Stewardship Pledge is incorporated, outlining community commitments.
d. Enforcement includes permit denials, entitlement revocations, fines, and liens for unpaid costs.
e. The agreement runs with the land, is perpetual (unless mutually terminated), and expires automatically if construction does not commence within five years.
The OAA seeks to ensure that the data center's development aligns with community interests, environmental standards, and City infrastructure capabilities while mitigating potential impacts.
FISCAL IMPACT:
As detailed in the attached Fiscal Impact Study and Economic Impact Study, the data center is projected to generate positive fiscal benefits for the City, including substantial property tax revenues from the redevelopment of the 20-acre site and ongoing utility income from the facility's mandated purchase of 100% of its power from the City's Electric Utility, with the single largest anticipated revenue being the electric use tax, which goes to the City’s general fund. All costs for electrical infrastructure upgrades, including enhancements to the Indian Hill Substation, are to be prepaid by Karis, with annual true-up reports ensuring no cross-subsidization by other ratepayers.