A county in Georgia is close to having a written set of rules for data centers, and the generator part is specific. The Walker County committee set up to draft development standards finished its review at its fifth meeting, WTVC (NewsChannel 9) reported on 27 October. What it has produced is a set of recommendations, not an ordinance. The committee will compile a revised draft for its next meeting.
Why the county is writing its own rules
NewsChannel 9 reported earlier that commissioners approved a moratorium in July that stopped the county from accepting new data center applications. Developers had made contact, but no application had been filed. The county has no ordinance written for data centers, and the planning director told the committee that an outright ban would not hold up legally. So the work went into conditions.
What the draft says about generators
- Emergency backup generators would have to meet at least EPA Tier 4, or newer technology that does as well or better.
- Routine testing would be allowed from 8 a.m. to 11 a.m. between 1 May and 30 September, and from 8 a.m. to 5 p.m. between 1 October and 30 April.
- A test session would be limited to 30 minutes, with a maximum of 10 hours a month and 120 hours a year. Running during a real power outage is exempt.
- No routine testing on days when the EPA air quality index is code orange or worse.
On sound, the proposed limits are 50 dBA for ambient noise and 65 dBC for low-frequency vibration, measured at the property boundary. A multi-day average would not count as a reading, so a single measurement taken while the plant is running is what a complaint would be tested against.
The rest of the package
Every applicant, whatever the size or ownership of the facility, would have to post a bond for decommissioning and site restoration. An earlier draft left that to the commissioners case by case, and the members struck it. Data centers could not cool from private groundwater wells; they would have to connect to a municipal water utility and use closed-loop cooling. They would default to industrial zoning on at least 10 acres, with a legal opinion still awaited on whether to confine them to industrial parks.
The committee's timetable: if its advisory report is in by 4 December, a draft ordinance could come before the Planning Commission in January and the Board of Commissioners in February.
Reading a test-hour cap before the commissioning plan is written
This is a recommendation from one county, but the shape is familiar from elsewhere (Virginia's Tier 4 rule, San Jose's draft). A Tier 4 floor, a test-hour budget and a boundary sound limit tend to arrive as a set, and they interact. Thirty minutes is short for a plant with many sets that all have to be exercised, and the yearly hours are shared between the routine runs, the commissioning load tests and any later re-test.
Before a site is fixed, find out how the hours are counted: whether a run on a load bank counts against the generator hours, who measures the boundary sound and when. Ask the permit office, in writing.
Sources: WTVC NewsChannel 9 (committee review), WTVC NewsChannel 9 (background)