Tier 4 Streamlined Data Center Permit

​​The proposed approach is only for data centers installing Tier 2 engines with pollution controls (operating at Tier 4 emission levels).

• Short-term NAAQS Compliance: (See DEQ's Short-Term NAAQS webpage for more information about these standards)

• 1-hour NO₂ NAAQS: The pollutant of concern for Tier 4 compliant backup engines is NO_X, since it takes approximately 15 - 20 minutes for Selective Catalytic Reduction (SCR, NO_X controls) to reach a desirable temperature to become fully functional. DEQ established a data center specific significant emission threshold (SET) of 50 pounds/hour NO_X for regularly scheduled testing and maintenance scenarios. This excludes emergency operation or commissioning (initial startup of a new engine). This SET incorporates the intermittent operation of these engines and deemed protective of the short-term standard. When facility-wide hourly emissions are below the 50 pounds/hour level, refined dispersion modeling for short-term NO₂ NAAQS compliance is not required.

• PM_2.5 NAAQS: DEQ determined that a SET for PM_2.5 is not necessary because any data center who wishes to use this expedited permit process will be required to install Diesel Particulate Filters (DPF) on the Tier 2 engines. DPFs can control PM_2.5 emissions immediately upon startup of the engine. Further, DEQ determined that a facility in compliance with the Data Center SET for NO_X, will also be in compliance with the 24-hour PM_2.5 NAAQS.
  

• SO2 NAAQS: SO₂ emissions are expected to be in compliance with NAAQS since sulfur content of fuel is limited by federal standards (New Source Performance Standards for Stationary Compression Ignition Internal Combustion Engines, NSPS IIII) and back up engines can only run on ultra-low sulfur fuel. Therefore, DEQ determined that a facility in compliance with the Data Center SET for NOx, will also be in compliance with the 1-hour SO₂ NAAQS.

• Cleaner Air Oregon Risk Assessment: DEQ developed a CAO Data Center Tool that conducts a risk assessment and produces annual and daily fuel limits based on stack and building heights, engine fuel usage and meteorology corresponding to a specific facility. This tool meets the criteria of a Level 2 Risk Assessment.
  

• Tier 4 Data Center Permit Template: DEQ created a data center permit template to standardize permit conditions for the data center facilities with Tier 4 compliant engines and to expedite permit drafting. ​

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A data center applying for a permit using this expedited process should expect the following permit conditions:

• All critical-load backup engines¹ are required to be EPA Tier 2 certified².
  
• All critical-load backup engines are required to have control technologies, including but not limited to:
• Selective catalytic reduction (SCR), diesel oxidation catalyst (DOC) and diesel particulate filter (DPF);
  OR
• SCR and catalyzed DPF (cDPF).
• Data centers can choose to demonstrate compliance with SET using one of the following two options:
• A Testing and Maintenance (T&M) plan and SET analysis.
• A SET analysis demonstrates how the facility will keep their emissions below the 50 lbs/hour NO_x SET. For example, a facility might elect to calculate hourly emissions below the 50 pounds/hour of NO_x by only operating two engines at a time. Calculations showing emissions below the 50 pounds/hour NO_x SET at all operating scenarios of the T&M have to be included.
  OR  
• Calculation of the maximum number of emergency generator engines that can be operated during one hour, using the equation in the permit template that DEQ developed for the short-term NAAQS compliance demonstration. This equation will be incorporated as a permit condition.

^​1 “Critical-load engine" is used here to refer to a stationary engine that supplies emergency backup power to equipment in one or more data center rooms. “Non-critical-load engines," by contrast, do not supply emergency backup power to equipment in data center rooms, but instead may be used onsite for ancillary facility-power needs, such as to back up load for cooling, security, or interior/exterior lighting.
² Certified to Tier 2 emission standards and 40 CFR 60 subpart III.​

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A complete application includes the following:

• Three Your DEQ Online Submittals
  
• ACDP – Standard and Construction Permit Application, including all necessary information required in Your DEQ Online (as required by OAR 340-216-0040 – Application Requirements)
• CAO – New/Reconstructed Source Risk Assessment Application, including a facility layout, report from the CAO Data Center Tool and corresponding AQ520 Emissions Inventory. The CAO data center tool report should be accompanied by a facility area map showing the location of all engines, all buildings, and the facility fence line.
• Note: A site-specific risk assessment is not required. DEQ will review the Emissions Inventory and CAO Data Center Tool Output, and if verified, the risk assessment will be approved and the submittal will be deemed complete.
• ACDP – Criteria Pollutant NAAQS Analysis, including the AQ402 Emissions Inventory.
• Note: A modeling analysis is not required. DEQ will review the emissions, and if verified, the submittal will be deemed complete.
• Applicable Fees (as required by OAR 340-216-8020 Table 2 - Fees and OAR 340-216-8030 Table 3 Fees);
• Standard Permit Application Fees
• Annual Fees, as applicable
• There is no NAAQS Modeling Fee for these applications
• Cleaner Air Oregon New Source Consulting Fee
• Cleaner Air Oregon Specific Activity Fees
• Level 2 Risk Assessment Fee 
• Community Engagement Fee, if applicable
• Toxics Lowest Achievable Emission Rate (TLAER) Fee, if applicable​