Generator Test Saves Power, Money

Is it possible to hug a tree while exercising a 2.1 Megawatt diesel generator? Not precisely. But 365 Main’s flagship San Francisco data center was able to save $70,000 in power costs last year from the local utility, Pacific Gas and Electric (PG&E), by altering the procedures for monthly testing of its backup generators. PG&E highlighted 365 Main’s efforts yesterday as part of a broader initiative to encourage data centers to reduce their energy use and impact upon the environment.

“365 Main is truly walking the walk in the data center segment, and we encourage other companies to follow its lead in order to protect all types of businesses from potential power outages on critical peak days and to preserve the environment,” said Al Steubing, PG&E Account Services Director. 365 Main is a participant in PG&E’s Critical Peak Pricing (CPP) program, designed to reduce stress on the good during periods of heavy power demand.

As part of its maintenance program, 365 Main tests each of its 10 Hitec generators once a month by running each of the 3,000 horsepower diesel engines for two hours. The company developed a new testing procedure that allowed it to reduce the use of load banks, the 8-foot tall heating coils traditionally used to test generators by drawing immense amounts of power. The new procedure reduced the facility’s utility power consumption by as much as 12.5 percent during monthly tests, and is compliant with guidelines set by the Bay Area Air Quality Management District (BAAQMD).

“The load bank draws enough power to test a 2 megawatt generator, but it also means an additional 2 Megawatts brought through the grid during the testing phase,” said Miles Kelly, VP of marketing for 365 Main.

J.P. Balajadia, 365 Main’s Vice President of Operations, was able to devise an alternate approach. “What JP was able to do was basically run the load being drawn by the building to the generator, eliminating the need for the load bank,” said Kelly. The technique is possible for data centers with exceptional equipment redudancy. An “N+1” approach insures that all key data center equipment has a spare on standby in case of an emergency. Kelly says 365 Main is engineered to an “N+2” standard, with two spare generators supporting the eight primary gensets for the facilty. Customers rely on that redundancy to remain online in case grid power is unavailable.

“The first question was, if we’re testing the generator using building load, are we no longer at N+1,” said Kelly. “The answer is no, because you’re only testing one generator and you have one more available as backup. That’s the beauty of an N+2 setup.”

Hundreds of PG&E business customers participate each year in the voluntary CPP program, which offers seasonal discounts to single-building customers that reduce energy usage away from peak periods between May 1 and October 31.

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About the Author

Rich Miller is the founder and editor at large of Data Center Knowledge, and has been reporting on the data center sector since 2000. He has tracked the growing impact of high-density computing on the power and cooling of data centers, and the resulting push for improved energy efficiency in these facilities.

One Comment

  1. There are programs like this all over the country. The concept is called Demand Response; the reduction of electrical consumption at the end-use customer level in response to high wholesale electricity prices, system resource capacity needs, or system reliability events. The reduction can be achieved through curtailment (e.g. turning off lights, raising temperature setpoints) or self-generation (e.g. turning on backup generators). End-users typically receive payments for participating. These programs are ideal for data centers as they typically have significant backup power and it's a great opportunity to test infrastructure and reduce exposure to blackouts. My company EnerNOC ( operates these programs for end users in 20 states and represents multiple data centers and telco facilities