Coefficient of Efficiency (COE) – The traditional definition of efficiency compares total input to total
output in one fashion or another. A COE for a data center should take into account the actual output of a data center and not just stop at the UPS (which is “just” an input to the processors).

A data center COE implies the total DC system efficiency. But looking at just UPS output only looks at the DC power efficiency and does not account for inefficiencies on the processor side. For a total system COE, input would still be average kWe (assuming that water consumption costs for cooling systems are minimal), but output could be measured as MB per sec, or something similar. The specific COE that was proposed would be more akin to a “COE-Power Conversion”, so as to indicate that it only looks at a sub-system of the total DC. (Marijn Braadbaart, CEM, Energy Solutions, Murphy Company)

kW of IT Load– Square footage is often used as a standard unit for providing a basic measure of the size and capacity of data center, but unfortunately the measure of square feet is not universal across all involved parties. Real estate professionals, IT managers, and building engineers each interpret square footages differently, which leads to confusion in the data center planning process and often results in a data center that is unable to accommodate future growth because it is literally out of floor space. kW of IT load is a more accurate and reliable metric than square footage for describing data center space and power requirements because it accurately reflects the power requirements of a data center based on the footprint of all the components that will reside above a raised floor space.

Data centers rarely have a homogeneous load profile, and while racks of blade servers may indeed possess substantial power requirements, the other components that will reside in the data center with them do not. Cabling and patch panels, for example, require no power at all, and other components such as network/telco (10-50W/sf) and spinning disk storage (100W/sf) have rates of power consumption considerably below those of high density servers. kW of IT load accurately captures this heterogeneous nature of real-world data centers, resulting in a metric that all parties can agree on and that will lead to a more successful data center development process. (Chris Crosby, Digital Realty Trust)

Premium Power – A term used to describe the service offered by Baltimore Gas & Electric, the regulated business unit of Constellation Energy. BGE (Baltimore Gas & Electric) introduced the program to provide electrical service on the customer’s side of the meter, which exceeded the utility’s tariff standards for voltage quality and reliability. The BGE “Premium Power Program” was the utility industry’s first program that focused on the unique needs of the individual customer. The program consisted of a site inspection, diagnostic testing, a solutions proposal and a turnkey solution including the appropriate scheduled maintenance and 7 by 24 emergency services to support the installed power conditioning, uninterruptible power supplies and/or standby generators to support the customer’s mission critical needs.

The “Premium Power Program” was administered by the Marketing & Energy Services Department of Baltimore Gas & Electric. The program was developed with and supported by the Liebert Corporation and its local representative: Ward-Boland Associates. (Arthur H. Beasman, CEM).