Proposed Karis Data Center At a Glance

The data center site is the prior location of a 2 million square foot office building built by ATT Bell Labs in 2000. The building was occupied until approximately 10 years ago.

In 2001 the approximately 150 acre lot was rezoned and sub divided into 3 lots. The 40 acre front lot zoned ORI (Office Research and Light Industry) where the proposed data center would be located, a 46 acer lot zoned ORI where the existing 60 year old Nokia building still exists, and a 64 acer lot rezoned R-3 for residential homes now known as Naper Commons where 227 single family homes and townhomes and a community park were constructed.

In 2023 after a majority of the homes were built and sold, the Naperville City Council changed zoning rules to allow for Data Centers to be built a a conditional use of the ORI (Office Research and Light Industry) Zoning District.

In 2025, Karis Critical initially proposed a two-building data center campus with two 211,000 square-foot data center buildings with 48 diesel generators.  The city planning and zoning department in working with the developer determined that there was not enough power available to power the two data center buildings and the developer reduced the the phase 1 development to a single building.

Petitioners' Proposal and Related Documents: https://naperville.legistar.com/LegislationDetail.aspx?ID=7721607&GUID=1C72BA9A-2B64-4906-97B0-A52251B93174&Options=&Search=&FullText=1

The proposed single building facility will have a total of 24 3-Megawatt Diesel generators. These generators will be approximately 4,000 horsepower similar in size to locomotive engines. While the generators will be used for emergency purposes they will each need to be tested for a minimum of 30 minutes per month - typically two at a time over the course of two work days.

While running generators will consume a large amount of diesel fuel - between 130 and 175 gallons per hour - and facilities such as this will require 12-24 hours of fuel on site for emergency purposes. Typically 70k to 110k gallons of fuel onsite far exceeding the 12,000 gallons of fuel that a typical gas station is allowed in Illinois.

The thunderous noise, earth shaking vibrations, and polluting diesel exhausts do not belong near homes.

Large data center facilities generate large amounts of low frequency noise due to large numbers of rooftop mounted cooling chillers that are used to cool the computer systems within the facility. These fans will run around the clock all the time.

The noise from the chillers can be heard for miles from the facility and can be the source of a large number of health related risks.

The single building will have 36 Megawatts of customer consumable power and a maximum power use of 43.2 Megawatts. This will be the single largest energy user in Naperville and will consume 40% of all of Naperville's power. 43 Megawatts of power can power between 43k and 86k homes.

80% of that energy will be provided by coal powered power plants that provide power to the City of Naperville.

The City of Naperville is attracted to the overall taxes that this facility will provide. While the developer has indicated that it could be as high as $3 million in total tax benefit due to the amount of electricity tax, the facility is unlikely to provide a third of those taxes due to the developer's unattainable best case estimates.