Soybean-based fuels are fouling up the best-laid backup plans of some data center pros.
Today, some data center managers wrestle with state government legislation that mandates the use of biodiesel over traditional petro-diesel -- mandates that are designed to wean states off petrol dependence and move toward more environmentally sustainable fuels.
But these alternatives pose risks. Derived from vegetable oils or animal fat instead of petroleum, biofuel blends can increase water and biological contaminants in fuel supplies. If handled improperly, biodiesel fuels can stop a data center's backup systems cold, according to a recent report from the Uptime Institute.
Biodiesel comes in different blends, which are referred to with the letter B, followed by a number that is the percentage of pure biodiesel. For example, B2 biodiesel is 2% biodiesel blend. B100 is pure biodiesel.
Minnesota, Washington and Oregon have biodiesel mandates. Minnesota mandates the use of B5 and will switch to B20 by 2015. Oregon and Washington currently mandate the use of B2. Biodiesel legislation is pending in Pennsylvania, New Mexico, Louisiana and Massachusetts.
Biodiesel backs up data center systems
Lamont Fortune, the lead mechanical engineer of data center facilities at insurance company UnitedHealth Group in Minnesota, knows firsthand how biodiesel can cause trouble for data center facilities. He was the driving force behind the Uptime Institute's biodiesel technical paper and co-authored it with Uptime VP Rick Schuknecht and other data center operators.
Fortune said the problem first cropped up two years ago, when UnitedHealth Group built a data center. The company started the design in 2006 and brought the facility online in 2008. UnitedHealth's data center design consultant wasn't aware of Minnesota's biodiesel mandate when the fuel-polishing system was installed.
"The manufacturer claimed the polisher could handle biodiesel, and particulate removal and water removal, but it could not do anything with the suspended water," Fortune said.
All fuel accumulates water in various ways – for example, exposure to humid air in transfer or through ventilation. But Fortune said biodiesel is more "hygroscopic" than petroleum-based diesel. "With petro-diesel, water separates out faster," Fortune said. "With biodiesel, the water tends to stay in suspension, and it makes the fuel look cloudy."
Today's fuel-polishing technologies can't remove the suspended moisture in a biodiesel mix. "As far as I know, there's no good coalescing media that can be used for removing suspended water. That's a chief problem," Fortune said. "That water can foul fuel nozzles on generator engines, and the only solution available is fuel additives to remove the moisture."
UnitedHealth is building another data center, and Fortune is installing an additional fuel tank, so that if the generator fuel accumulates too much water, Fortune can siphon it out and use it in the boiler for heating, which is more forgiving of water in the systems. Fortune isn't happy with this resolution, but he's making it work, he said.
"There are a lot of people that say they'd never use biodiesel in a mission-critical facility. But in Minnesota, you don't have a choice, because it's the only thing you can buy," he said. "Biodiesel's shelf life is not as long, and that changes how you manage fuel volumes, and you need to do periodic testing."
Uptime Institute members can download the group's biodiesel technical white paper for equipment recommendations and best practices. A free biodiesel handling and usage guide is also available from the National Renewable Energy Laboratory.
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