The Energy Efficiency Opportunity for Data Centers
Improving the energy efficiency of data centers can save hundreds of thousands of dollars each year, which makes the business more competitive and the operations more reliable.
The rate of energy used by a typical rack of servers, drawing 20 kilowatts of power, equates with that of a fleet of 70 hybrid cars. One of these cars could make 340 coast-to-coast trips across the United States for each year that the rack runs. This server rack also guzzles more that $17,000 per year in electricity. A major data center recently in the news [download] was said to draw 8 megawatts of power (corresponding to an annual cost of $7 million (and potentially double that if air conditioning is included), assuming 7x24 operation and an electricity cost of $0.10/kWh).
Efforts to improve energy efficiency in data centers can pay big dividends. Among the findings of a design charette [download] held in 2003, an integrated strategy could reduce energy use in the typical data center by almost 90% [chart]. But, where to start?
With typical annual energy costs [chart] per square foot 10-times (and up to 100-times) that of typical office buildings, data centers are an important target for energy savings. They operate continuously, which means that their electricity demand is always contributing to peak utility system demands, an important fact given that utility pricing increasingly reflects time-dependent tariffs. Energy-efficiency best practices can realize significant savings while maintaining or improving reliability [presentation], and yield other non-energy benefits.
Data Centers are prevalent in both public and private sector buildings serving many growing sectors of the economy. The development of the World Wide Web, and the shift to smaller, multiple unit servers has created a unique challenge to electrical power infrastructure. Advances in information and computer technologies have allowed greater and greater processing in smaller components. Energy efficiency improvement of the equipment involved, however, has not evolved proportionally to component size reduction. This situation has lead to increasing energy intensity levels within computer facilities, and acute problems with rising heat output that are actually beginning to limit productivity [download] (number of servers that can be hosted) and force major capital investments to expand and power the air-conditioning systems. To compound the problem of increasing intensity, there is considerable discrepancy between the electrical demand projected by developers and building owners and the actual electrical consumption. As these facilities are planned, and then built, overstating the electrical load coupled with use of outdated cooling practices often leads to inefficient operation. Because the energy intensities are increasing there also has been a tendency to exaggerate the impact of these facilities on the electrical power grid. Prior investigations suggest that there are significant opportunities for energy efficiency improvement in within these facilities, such as individual systems that support data center operations, the interface of building systems and computer arrangements, and more efficient design within the computer boxes. While improving each piece of the efficiency puzzle provides important gains, an integrated approach has the potential for 30-50% improvement.
"You can't manage what you don't measure" is a mantra often recited by corporate leaders. To support this way of working, this website presents a selected distillation of the extensive benchmarking in 22 data centers which formed the basis for the development of best practices for design and operation that summarized how better energy performance was obtained.
For a brief overview of the energy management philosophy underlying this website, read our article [download] from HPAC magazine. For a real-world case study, with savings of 55%, see the paper by Blazek et al [download].
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