The Oregon Department of Environmental Quality's slides on data center air quality permitting, dated July 31, 2026, are about the air permits of Oregon's data centers and the diesel generators that provide their backup power. Parts of them follow, not the whole.
The Generators on the Permits
The slides count 39 permitted data center campuses in Oregon: 16 in Hillsboro, 3 in The Dalles, 16 around Boardman, Hermiston and Umatilla, and 4 around Bend and Prineville. Another slide gives the total number of large generators as 2,482, with a total capacity of 6,328 MW.
The slides describe the machines as diesel emergency generators, "used to provide backup power during emergency events related to loss of utility power." They burn ultra-low sulfur diesel fuel and/or renewable diesel; biodiesel, the slides say, "is not currently allowed at any data centers due to different emissions profile."
How They May Run
Normal operation, in the agency's account, is testing: "Biweekly readiness testing for 30 minutes" and annual load testing. Emergency operation is "Rare and related to utility power loss," and, the slides add, "Could increase over time with increased power demand and grid reliability issues."
"Non-emergency" operation, such as maintenance, readiness testing and dispatch operations, is "limited to 100 hours/year," and "Most permits have more restrictive operational limits." The agency, the slides say, evaluates compliance "with all applicable state and federal regulations" for normal, non-emergency operation. The terms the slides name include facility-wide emission limits, emissions standards for each stationary generator, generator-specific toxic air contaminant emission limits, operational limits on hours of operation and/or fuel use, maintenance requirements, emissions testing, and recordkeeping and reporting.
Dispatch Operation and Streamlined Permitting
One slide is headed "Dispatch operation." Dispatch operation, it says, "Could be used to increase grid reliability." Power "is provided only to the facility itself." Dispatch is "Defined in federal regulations." It is "Limited to 50 hours per year, part of 100 non-emergency hours," and each permit carries additional site-specific emissions and operating limits.
And: "Currently not permitted at most data centers."
The slides also describe a streamlined permitting option, available since 2025, for data centers that install generators with all three available emission control devices, or equivalent technology. The agency "has not issued any streamlined permits yet, but there is a growing interest."
Sources
- Oregon Department of Environmental Quality. Data Center Air Quality Permitting (presentation slides). 31 July 2026. regulator