The Green Grid’s PUE seen as preferred industry metric

The Green Grid announced on 15th July that the Power Usage Effectiveness metric, which it published in 2007, has now achieved industry alignment specific to recommendations on how to measure PUE in dedicated data centre facilities.

The organization’s report, “Recommendations for Measuring and Reporting Overall Data Centre Efficiency – Version 1 – Measuring PUE at Dedicated Data Centres,” documents the combined recommendation of The Green Grid in collaboration with 7×24 Exchange, ASHRAE, Silicon Valley Leadership Group, U.S. Department of Energy Save Energy Now Program, US Environmental Protection Agency’s Energy Star Program, United States Green Building Council, and Uptime Institute.

“Driving industry alignment of PUE through consistent measurement and reporting processes represents a significant step in improving data center energy efficiency,” says Dan Azevedo, Symantec representative and Board member of The Green Grid. “The guidance specific to calculating PUE for data centers that use multiple energy sources (electric, natural gas, water, etc.) is substantial to ensuring PUE is measured and reported equitably. This task force is working to drive clear, consistent recommendations with a single voice”

Keysource says; Keysource were one of the first UK companies to sign up to become a member of the Green Grid in March 2007. Keysource appreciated this metric because of its simplicity; the metric identifies data centre infrastructure efficiency by comparing the total amount of energy consumed by the data centre to the total amount of energy consumed by the IT equipment.Ongoing measurement and fine tuning is the key. There is no question that the correct approach to energy reduction is to start measuring and establishing a ‘baseline and track performance’.  The PUE metric is a great starting point and easy to understand, however to truly uncover the potential savings, companies need to establish a robust, ongoing energy reduction programme. 

Cooling measures for data centres

Energy efficient design of data centres is very important, particularly as we enter these more energy-sensitive times. Cooling is the largest power consumer within a data centre infrastructure – more so than the IT equipment itself. Therefore it’s essential to pick the right cooling solution to improve facility energy efficiency and reduce operational costs.

To explain further, server cooling  represents one of the critical challenges in data centre and other related technical spaces. Similar to a typical PC, servers require a power supply and need to expend heat roughly equal to the total electrical power input to the device. So air conditioning supply is an important design factor for technical spaces.

Mapping data centre airflow

Some companies use computational flow dynamics (CFD) software to model data centre airflow ; creating a 3D model of technical space. Not only does this software give an invaluable proof of concept, it shows key stakeholders a clear picture of how the facility will operate.

Recent data centre cooling project

Keysource’s expertise in data centre cooling involved them implementing a recent staged upgrade at Elsevier’s Kidlington data centre in Oxfordshire.  This project involved minimum disruption to working conditions for this leading science and health publisher. Half of the data centre air conditioning units   were replaced one by one. And ceiling returns and a very early smoke detection alert (VESDA) were installed to address air-flow issues.

The expertise demonstrated on this project has involved the company being re-engaged in electrical upgrade project with the publisher.

Show me the figures

Original article written Jessica Twentyman and published on Sourcing

In the race to deliver ‘green outsourcing’, are providers doing enough show customers robust evidence of their green credentials? The answer, according to the 2009 Green Outsourcing Survey from Black Book Research, is a resounding ‘No’.

“The outsourcing industry is saturated with “green speak”, of which the majority is deemed [to be] just hype by user CIOs and vendor sales people,” say the report’s authors. “Both vendors and users continue in a stage of confusion about where and when they should invest their time and money.”

One metric that is starting to play a part in discussions between providers and prospective customers is Power Usage Effectiveness (PUE). First proposed by The Green Grid, an industry forum of IT vendors and end-user customers, back in 2007, PUE is today a widely accepted form of measuring data-centre efficiency. In April 2010, it was announced that government agencies in the US, Europe and Japan are all planning to adopt and use PUE.

A PUE calculation analyses the relationship between ‘Total Facility Power’ (TFP) and ‘IT Equipment Power’ (IEP). By dividing TFP (the energy consumed by power components, cooling elements and other infrastructure such as lighting) by IEP (the energy that powers servers, storage devices and networking equipment), IT teams arrive at their facility’s PUE score. A PUE score of 3, for example, indicates that data centre energy consumption is three times greater than the energy necessary to power its IT equipment. Ideally, PUE should be less than 2 to 1; the closer to 1 to 1, the better.

PUE is a useful benchmarking tool for measuring and monitoring efficiency improvements in an individual facility, says Andy Hayes, Associate Director at Keysource, a company that designs and builds new, energy-efficient data centres and improves existing ones to optimise their energy consumption. Energy assessments, based on calculating PUE, have played an increasingly important part in engagements in recent years, he says, as the cost of electricity has risen. In a recent data centre project for Yorkshire Water, for example, Keysource calculated the PUE score for the company’s facility to be 2.3. In other words, only 43 percent of the total facility power was being used to power IT equipment. After incorporating Keysource’s recommendations for better cooling and airflow management, the PUE score had improved to 1.7 – meaning that 59 percent of TFP is now consumed by IT. That improvement in PUE score also resulted in a potential annual saving of up to £70,000 per year.

But PUE is far from ideal as a means for outsourcing customers to compare one data centre facility to another, says Daniel Lowe, managing director of managed hosting company UKSolutions. “A highly available infrastructure is typically going to have a poorer PUE because of the overheads involved in building in resilience, but that supplier may offer better uptime guarantees to its customers,” he argues. That’s not to say that UKSOlutions isn’t interested in making its facilities as energy-efficient as possible – the company has already done much work on cold-aisle containment, using blanking panels to fill gaps between machines, and repositioning cables to keep them cool, he says. But he just doesn’t see PUE scores as an effective way for the company to market itself as ‘green’.

Perhaps a more blended approach is needed? Glenn Fitzgerald, lead architect and data centre expert at Fujitsu, certainly thinks so. Fitzgerald was a key figure in the development, design and building of the new Fujitsu data centre London , which opened in 2008 in Stevenage. Its PUE rating is 1.6 when fully loaded compared, but it is also the first in Europe to be independently certified to the Uptime Institute’s international data centre Tier 3 standard, which measures availability as well. “Resilience and energy efficiency are equally important dimensions of data-centre quality for our customers, which is why we ensure we can provide good measurements in both areas,” says Fitzgerald. Once London North reaches its full capacity, he says, Fujitsu is planning a new data centre that uses wind and wave power alongside National Grid power.

Even representatives of the Green Grid advise against relying on PUE as a means to compare the efficiency of one data-centre facililty against that of another. “It’s a relational metric,” explains Vic Smith, chairman of the Green Grid’s EMEA Technical Working Group. “It provides a way for companies to measure their own progress in using energy more efficiently, to map their journey between a PUE of X to a PUE of Y, but not to compare facilities. That’s not how it was ever intended to be used.”’s advice to would-be outsourcing clients? Ask your IT outsourcing provider about what PUE score they achieve in their data centre facilities – it can’t hurt and it will show them that you’re in touch with Green IT issues. Ask them what measures they’ve taken to improve their score and the results they’ve seen as a result.

But also ask them for stats on reliability and availability, too. After all, few companies are so environmentally-friendly that they’re ready to sacrifice the resilience of vital business processes on the altar of meeting carbon reduction targets.

Keysource’s energy assessment improves Yorkshire Water’s data centre efficiency by 25%

Yorkshire Water was looking to gain a greater understanding of the performance of its data centre facility and associated operating costs to enable the company to manage its IT infrastructure more closely and more responsibly.

Yorkshire Water appointed Keysource to conduct an Energy Assessment to provide a review of its data centre’s energy use and see how the company could reduce overall operating costs and the environmental impact of the facility. Following the survey and recommendation report from Keysource, Yorkshire Water implemented a number of suggested changes which resulted in a reduction in energy consumption of more than 25 per cent with a potential annual saving of up to £70,000. 

Shakil Azam, IT Service Provisions & Data Centre Manager commented: “Keysource’s Energy Assessments and recommendations proved essential for our ongoing commitment to reducing energy consumption from our IT infrastructure. By working closely with Keysource, we have tapped into their extensive data centre knowledge and expertise, to achieve significant performance gains in terms of reduced costs and carbon emissions.”

Visit our projects page to read the full case study.

Keysource says; Our innovative approaches to data centre efficiency and measurement has set new standards in terms of the savings and PUE that are achievable. The Yorkshire Water project demonstrates that measurement followed by implementing best practice recommendations can prove very attractive indeed when the power savings available are assessed.

Can we tender for your new data centre design and build project? Could your facility benefit from an energy efficiency assessment? Please get in touch


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