Analysts laud efforts like the NCTD's but warn that solar power isn't right for every data center. "The level of efficiency you can get out of solar energy is dictated by the location of the data center," says Forrester Research analyst Doug Washburn. "If you are in an area where the sun shines more frequently, you can take advantage of a solar investment."
One reason why solar may not be the best data center power source is the fact that data centers use 10 to 100 times more energy per square foot than a typical office complex, Washburn says. Moreover, resiliency and uptime are so crucial to a data center's operation that "it's a critical risk, and maybe even foolhardy to think you could power the majority of your data center from solar," he adds.
Washburn agrees that virtualization is key to the success of a solar project. Increasing the number of hosts per machine, consolidating storage and decommissioning equipment that has been virtualized can make a data center more efficient even before an energy switch-over, he says.
Power from jet engines
Christopher Sedore, the CIO at Syracuse University, says the upstate New York school spent about $12 million to build a data center that uses natural-gas-fired microturbines from Capstone Turbine to generate power on-site.
Microturbines are essentially jet engines that run on natural gas and provide power to generators. The turbines produce about a half a megawatt of power for the university's data center and another 200 kilowatts for other uses, such as powering an adjacent building.
The turbines enable the university to have a co-generation setup, meaning they can help generate both heat and power for the data center or nearby buildings. The university can also sell any extra power the turbines generate back to the local power company.
The turbines drive two 150-ton absorption chillers that turn the heat exhaust from the turbines into chilled water that cools the data center. In the winter, the university uses cold outside air for data center cooling, and hot water generated by the turbines is used to heat an adjacent building.
Banking on fuel cells
One of the most promising new technologies for powering data centers is the hydrogen fuel cell. Hydrogen fuel cells don't produce any harmful emissions, so companies such as Verizon, Whole Foods and Google have adopted them as an alternative power source for office or retail space.
Few organizations use fuel cells to power data centers, because they are expensive. But First National Bank of Omaha built a 200,000-square-foot fuel-cell-powered data center in 1999 because such systems tend to be especially reliable. The data center is about the size of a football field; it's surrounded by a dry moat and is powered entirely by four 200-kilowatt fuel-cell generators. If the data center does lose fuel cell power, which is extremely unlikely, an uninterruptible power supply can carry a short-term load.
"With the fuel cells, we have seven-9s of reliability, or about 2 or 3 seconds of downtime per year," says Brenda Dooley, president of First National Buildings, a bank subsidiary that handles corporate real estate and facilities management. "We came from a system with backup batteries. When we'd lose power, the batteries just wouldn't be there. We did this for reliability."
Dooley explains that the credit card processing that's done at the data center requires high reliability: Just one hour of downtime could result in a loss of as much as $6 million.