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The green grid opportunity


With energy shortages and energy costs taking top rank among the concerns of our times, a movement to decrease data centre and other IT energy usage patterns is gathering momentum, writes Rodney Callaghan, MD: Southern Africa of the critical power and cooling services division of Schneider Electric.

A key step has been the formation of The Green Grid. Founded in February 2007, this growing industry organisation seeks to define and propagate the best energy-efficiency practices in data centre operation, construction and design.
The need for data centres to go green
Until recently, electricity usage wasn’t a major IT concern. Servers didn’t draw much power and their density in data centres wasn’t significant enough to create any concern. All this has changed with the growth of the Internet and the world’s businesses, governments and other institutions.
At Gartner’s 25th Annual Datacenter Conference in November 2006, electrical power consumption was a headline issue. Gartner analysts at the conference predicted that half of the world’s data centres will run out of power by the end of 2008.
With the advent of high-density computer equipment such as blade servers, many data centres have maxed out their power and cooling capacity. It’s now possible to pack racks with equipment requiring 30 000 watts per rack or more in connected load. A few years ago, it was only 2 000 to 3 000 watts per rack.
The density of IT equipment per cubic metre is 20 to 50 times what it was 50 years ago. Of particular concern is that power consumption is rising faster than the average data centre can accommodate. It’s not just a matter of building out of space to house new servers; IT also needs to add additional electrical capacity and cooling systems.

Power consumption: an issue throughout the data centre
Electrical power needed to run today’s high performance data centre servers is only part of the problem. Non-IT devices that consume data centre power include such things as transformers, uninterruptible power supplies (UPSes), power wiring, fans, air conditioners, pumps, humidifiers and lighting.
Virtually all the electrical power feeding the data centre ultimately ends up as heat. Unfortunately, according to Gartner, the vast majority of hardware devices have been designed to provide maximum functionality and performance with little regard for wider environmental issues.
Gartner research vice president Rakesh Kumar says traditional data centres typically waste more than 60 percent of the energy they use to cool equipment. Another inefficiency is that of vendors putting inefficient power supplies in high-volume servers because they don’t see a competitive advantage in putting in more efficient components.
Jon Koomey, a consulting professor at Stanford University, calls this a "perverse incentive that pervades the design and operation of data centres".
For instance, commonly used power supplies have a typical efficiency of 65% to70% cent and are a huge generator of waste heat, while units with efficiencies of 90% or better are available and pay for themselves over the life of the equipment.
Power conversion is also a potential area of significant improvement when it comes to data centres. From the time power enters into a data centre until the time it reaches a server’s microprocessors, power is converted many times. A study by a major microprocessor manufacturer found that IT data centres typically burn more power in power conversion and cooling at light loads (zero to 25 percent platform utilisation) than the computer systems are using. That means there are significant opportunities for energy saving in the design of power conversion and cooling systems that scale better with the load.
The need for better data centre metrics
To cope with the coming power crisis for data centres, companies will need to retrofit existing facilities, build new ones, or risk running out of capacity for growth. The power and cooling issues facing large IT organisations are being driven by the following factors:
* The increase in computing demand;
* The increase in IT equipment power density;
* The increase in energy cost and its subsequent importance as a significant part of the total cost of ownership (Gartner estimates that energy bills traditionally have accounted for less than 10% of an overall IT budget, but could soon account for more than half); and
* The availability of power to meet computing demands.
Data centre managers need a standard set of metrics to understand the efficiency of their data centres, improve the performance-per-watt of their IT equipment and make smarter IT purchases.
Conventional models for estimating the electrical efficiency of data centres are grossly inaccurate for real-world installations. For power equipment, efficiency is typically expressed as the percent of power-out to power-in. For cooling equipment, efficiency is typically expressed as the ratio of heat removed to electrical input power (coefficient of performance).
Unfortunately, these individual values of efficiency often leave people to think that the efficiency losses of a data centre can be determined by simply adding up the inefficiencies of various components. Unfortunately, this approach does not provide accurate results in the case of real data centres. In fact, it can cause data centre designers to overestimate efficiency and consequently underestimate the losses or over-provision for these losses.
Going green through the green grid
The Green Grid ( is a global consortium dedicated to advancing energy efficiency in data centres and business computing ecosystems. A non-profit trade organisation of IT professionals, The Green Grid’s charter is to address power and provide industry-wide recommendations. Green Grid members include leading technology companies (AMD, APC, Dell, HP, IBM, Intel, Microsoft, Rackable Systems, SprayCool, Sun, and VMware).
The Green Grid has identified both short-term and long-term objectives to increase the energy efficiency of data centres and IT infrastructure equipment around the globe. In the short-term, the organisation seeks to define a way for facilities organisations, IT managers, CIOs, regional power utilities and governmental regulatory agencies to evaluate the performance-per-watt of the data centre and their components (including islands or sub-components of the data centre).
While there are metrics today, which are used to gauge the performance of the data centre, their usefulness falls short when measuring data centre performance-per-watt. One such metric that has been used for years is data centre density (DCD). The primary use for this benchmark is to determine if the deployment is low-, medium-, or high-density.
This is a great metric to determine the absolute performance of a data centre relative to other data centres, but it fails to capture whether the deployment is being done effectively. When taking a holistic view of the data centre, it becomes clear that current metrics such as DCD, measured in kilowatts per square foot, are not useful metrics for data centre efficiency since the power to cool and convert power for the IT infrastructure in a data centre is now greater than the power used by the IT equipment itself.
The question of data centre energy efficiency really starts at the electrical meter coming in from the utility and needs to look at how much of that power coming in is actually being used to by the IT computing infrastructure to do work. Once that can be determined, it will be easier to pursue three Green Grid goals:
* Minimise the power needs of the data centre.
* Maximise the percentage of that power coming in that is used for IT computing work.
* Minimise the amount of power spent on non-IT computing equipment.
Other short-term objectives of The Green Grid include the publication of best practice white papers and checklists, definitions of standard workload and deployment models, engagement with other relevant standards organisations and extensive engagements with data centre operators to define key energy efficiency requirements going forward.
A new data centre power efficiency architecture
Long-term objectives for The Green Grid include defining a new data centre power efficiency architecture to implement energy efficiency policies natively through the instrumentation of devices. This architecture will include automatic control of data centre components via policy-based management geared toward IT objectives for power efficiency. Included in this effort will be specifications, as well as compliance and interoperability testing linked to a Green Grid logo programme.
To develop this architecture and set of specifications, much groundwork needs to be done in proposing, aligning and defining each element. To do this, The Green Grid has organised a governance body (board of directors), communications committee and technical committee.
Progress will require an industrywide effort In order to achieve its long-term objectives, The Green Grid needs industry participation. Membership of The Green Grid is open to IT professionals who are concerned or chartered with data centre operations and facilities management.