By Dan Bodenski, Director of Strategic Solutions, Electronic Environments Corporation
Power Usage Efficiency (PUE) is currently considered one of the most important metrics a data center team can utilize to assess a data center’s current and potential energy efficiency. PUE is the term we use to define the ratio of total energy consumption throughout a data center including all fuels, divided by the total energy consumption of IT equipment. This go-to metric was originally developed by the Green Grid Association in 2007, created as a way to definitively measure and track data center efficiency. Since its inception, the PUE metric has expanded its usefulness outside of a simple end-user tool for operators. Today, PUE is considered by many a Key Performance Indicator (KPI) of a mission-critical data center facility.
According to Green Grid, three separate levels exist for the measurement of PUE, each providing their own benefits and requirements:
- The first level, known as “basic” measurement, measures IT equipment energy at Uninterruptible Power Supply (UPS) output on a weekly or monthly basis;
- The second level, known as “intermediate” measurement, allows energy to be measured at the Power Distribution Unit (PDU) outputs;
- The third level, the most accurate measurement, requires a high level of technology coordination, data collection and human interaction. A great way for facilities to reach this level of accuracy is to install a PUE measuring device such as a kWh meter with help from an experienced firm.
Whether their roles focus on design and engineering, operations or C-level management, key stakeholders within the data center leverage PUE as a core determinant for evaluating and analyzing a facility’s effectiveness and potential. When PUE data is used properly within a mission-critical environment, the results can justify added environmental enhancements and enable cost savings through increased energy efficiency as well as revenue growth from monetizing access server capacity.
So, how do the different players in the lifecycle of a data center really view PUE? Designers, engineers, operators and executives all have their hands in different aspects of the facility, so it would stand to reason that each has their own approach to using PUE in order to fulfill their specific role. Below, we’ll take an insider look into how each of these stakeholders leverages PUE to satisfy customer demands and create a more efficient, mission-critical environment.
Designers / Engineers
De sign and engineering teams are continually pushed to develop mechanical and electrical designs that will drive energy efficiency while simultaneously ensuring maximum uptime and enabling continued innovation. This balance can be achieved by understanding and considering the PUE of a facility, which provides a transparent view into its energy consumption.
In some cases, taking advantage of the surrounding environment as well as documented, low risk strategies such as increasing the supply air temperature and/or chilled water temperatures can mean big savings. To get the best results, design teams should adhere closely to Green Grid’s PUE definition of components during initial design and analysis while properly identifying source energy; this will ensure that PUE calculations presented in the initial design will match the ultimate results.
Today’s data center operations team are under serious pressure to reduce energy use within existing data centers; however, these solutions must fit within the framework of a live, operational facility. Management of real-time planning activities and ensuring maximum availability of critical infrastructure are at the top of operators’ responsibilities lists. Not far behind is PUE, which provides operations teams with a KPI to deliver and report upon to senior management on a regular basis. Through this deep understanding of a facility’s energy usage, operators justify new and effective ways of reducing power loss and saving energy.
C-level data center executives take a big-picture approach to data center energy effectiveness, and PUE plays an important role in influencing their overall strategies. PUE represents approximately 8 to 15 percent of the Total Cost of Ownership (TCO), and requires regular monitoring and analysis because it is a KPI that executives often tout to corporate clients and potential third-party customers.
In order to have a successful, energy efficient mission-critical facility, these varying perspectives on PUE must be considered by the entire data center team, not just each stakeholder for their specific professional purpose. Through this combined effort and 360-degree approach, the full mission-critical team can ensure long-term facility success.