Forming Energy-Saving Partnerships with U.S. Computer Data Centers
From the Spring 2007 issue of Energy Matters
Large, high-performance computing systems like this one at a research facility often require a considerable amount of energy to run and to remain reliable. (Credit: Jack Dempsey)
As the demand for computer processing power continues to grow, so does the demand for energy to keep large computer data centers running. The nation's computer data centers are thus prime candidates for energy-saving solutions like those proposed as part of a U.S. Department of Energy (DOE) and industry partnership strategy.
Many top U.S. economic, scientific, and technological organizations depend on large computer data centers for their essential computing needs. Running computer systems, servers, and components in computer data centers can require a considerable amount of energy. To support their computing systems, most centers provide redundant cooling and power distribution backed up by standby electrical systems. These have been shown to consume as much energy as the information technology (IT) equipment they support.
Small wonder, then, that In 2005, U.S. computer data centers consumed approximately 45 billion kilowatt-hours of electricity, or about 1.2% of all the electricity used in the nation, according to a study by energy and environmental scientist Jonathan Koomey.
To help computer data centers operate more energy efficiently, the DOE Industrial Technologies Program (ITP) is working with the centers themselves and with equipment suppliers and staff in the DOE national laboratories to explore partnership opportunities that could lead to significant energy and cost savings, reduce the burden on the U.S. electricity grid, and increase the reliability of critical computer operations.
Outfitting computer data centers with energy-efficient technologies and providing energy-saving assessments and best practices can also help to curb increases in electricity demand and carbon emissions. And these measures can allow utilities to postpone the construction of new electricity generation capacity.
Meeting the Unique Challenges Posed by Data Centers
Today, computer data centers are using more compact and energy-intensive servers than the ones used in the past. As the number and size of the centers increase in response to the growing demand for processing power throughout the economy, so does the amount of energy they require. This rise in demand places an extra (and serious) burden on the already strained U.S. electricity grid and poses a threat to the centers' reliability. According to a recent survey, computer data centers average at least one serious power outage per year.
Maintaining reliability and managing the rapid growth in new technologies are priorities for computer data centers; energy-efficient technologies and best practices must take those priorities into account. Energy-saving practices must be updated continually to keep up with continual changes in computer technologies, which tend to evolve faster than the equipment needed to power and cool them. Moreover, the tools needed to model energy management and heat transfer in computer data centers can be complex and expensive.
With these considerations in mind, partnerships could include strategies such as these:
Build on DOE's highly successful Save Energy Now program and the Energy Savings Assessment process to benchmark computer data center energy use and identify opportunities to reduce demand by 10% to 20% through energy-efficient practices.
Perform energy savings assessments to identify near-term electricity demand reduction measures with short payback periods, and train computer data center managers and designers in energy management best practices and tools.
In partnership with industry, develop and deploy a curriculum and process for certifying Data Center Specialists with the expertise to assist center operators in improving energy efficiency.
Become a clearinghouse for disseminating information about energy-saving opportunities and best practices to computer data centers.
Develop new software tools to profile computer data centers' energy use and analyze energy-efficiency needs to help uncover savings opportunities.
Conduct research in methods to reduce computing system equipment loading and provide cooling and power more energy efficiently.
Identifying Energy-Efficient Technologies and Best Practices
Lawrence Berkeley National Laboratory (LBNL) has been contributing to this effort by conducting benchmarking studies of energy use in actual computer data centers to help determine the savings potential. To date, LBNL has identified about 70 best practices for optimizing energy efficiency and performance in computer data centers. These practices are applicable to mechanical systems (airflow management, air handler systems, humidification, and plant optimization); IT equipment selection; electrical infrastructure; lighting; and commissioning.
In addition, case studies have been developed that highlight the considerable savings possible when computer data centers identify and implement energy-efficient equipment and practices. An example is the computer data center housed in Building 700 of the Fleet Numerical Meteorology and Oceanography Center at the Naval Postgraduate School in Monterey, California. That center is home to a very large computing operation and thus has an extremely high heating, ventilation, and cooling (HVAC) load.
The center's HVAC systems consist of eight air-handling units (AHUs), three chillers, two condensing units, and two hot water boilers, as well as chilled water and hot water pumping and distribution systems. A steam boiler provides humidification control for the computer rooms. Between December 2001 and November 2002, the Navy spent more than $503,000 for electricity and natural gas in Building 700.
A report (PDF 1.08 MB) issued in 2003 describes a study of Building 700 performed by AEPC Group, LLC, in conjunction with Cogent Energy, Inc., under the direction of LBNL staff. Download Adobe Reader. The study identified and recommended five potential HVAC energy-saving opportunities with both economic and operational benefits. These involved making energy-saving modifications to all eight AHUs, installing economizers on two AHUs, and installing variable-frequency drives on three chilled water pumps. An energy management and control system was also recommended.
Implementing those measures could reduce energy consumption in Building 700 by more than 1,537,600 kilowatt-hours of electricity, or 26% of the adjusted baseline, and nearly 56,000 therms of natural gas, or 42% of the adjusted baseline. In all, the recommended measures could trim utility costs by about $231,000 per year. At an estimated cost of about $506,000, these measures would have a simple payback period of about 2.2 years, and even less if rebates can be obtained.
Partnering to Improve Efficiency
You can be part of the effort to improve the efficiency of computer data centers by getting involved in this partnership. Visit the Industrial Technologies Program's Data Center Web site to learn how ITP and others are meeting computer data center efficiency challenges. Register to receive regular updates and to serve on a technical working group to participate in product and protocol development.
For more information, please contact the EERE Information Center, 1-877-337-3463, and read about creating energy-efficient computer data centers (PPT 2.7 MB).
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