Who counts the test hours on a data center generator fleet? In San Jose it may soon be the city as well as the air district. At a community meeting at City Hall on 15 October, staff presented draft standards for data centers and research facilities that draw 20 MW or more. Backup generators would have to meet EPA Tier 4, and running them for testing and maintenance would be limited to 25 hours a year, half of the 50 hours California rules allow, KQED reported the next day.
What the Draft Asks For
Deputy city manager Manuel Pineda set out the requirements and how they would be enforced, according to CBS San Francisco. The air district would police the generator rules. Projects would file yearly reports on noise, sewage, energy and water, and a project that falls short could be fined or told to add measures. KQED adds that water and electricity figures would be checked by a third party every five years.
- Noise: sound barriers around outdoor equipment and a city noise monitoring programme.
- Water: recycled water for cooling or a low-water design such as closed-loop or air cooling; Hoodline reports that drinking water in open cooling systems would be ruled out for sites of 20 MW and above.
- Power: a fully carbon-neutral electricity supply.
- Neighbours: mailed notice of a new project out to 1,500 feet instead of 1,000.
The draft draws no line between a data center and an R&D building above 20 MW. CBS points to Google's project in Alviso, a research facility on paper that could draw 250 MW at full capacity. The city has 11 data center applications under review, and Hoodline says that once the rules are adopted, projects already in the pipeline would be checked against them.
December Vote, Residents Still Unconvinced
The timetable is short. Final draft standards are due at the Planning Commission on 18 November, the council is expected to take them up on 8 December, and the second reading is set for 15 December. The ordinance would take effect 30 days after that.
Many at the meeting wanted more. San Francisco, Oakland, Richmond, Gilroy and Oakley have passed temporary moratoriums, and residents asked San Jose to do the same. Mayor Matt Mahan has dismissed a ban as a way of avoiding the problem. Residents also pointed out that the standards cover testing only: when the grid goes down and the generators run for real, the cap does not apply.
Living With a 25-Hour Budget
For anyone commissioning or maintaining a fleet in that city, the hour cap will bite before anything else. Monthly runs, the annual load test, a retest after a repair and any run to clear a fault all come out of the same 25 hours per engine, so test plans need to be written before the units arrive, not after. Where the full-load run is done on a load bank, the order of the tests and how long each one lasts start to matter.
The Tier 4 requirement moves work earlier too. On large diesel generator sets it usually brings exhaust aftertreatment with it, and that needs room, reagent storage and a service plan in the layout from the first drawing. Worth asking any supplier now how many hours their own factory and site tests use, and whether those count.
Sources: KQED, CBS San Francisco, Hoodline