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Can smart metering and dynamic management ease the data centre energy crisis?

Lay a map of a national electricity grid and the plans for a data centre side by side and there is more than a passing resemblance. This is hardly a surprise: a typical data centre – which covers 5,000 square feet – can easily consume five megawatts of power, around the same as a small town.

Nor do the parallels end there. Just as householders have faced rising energy bills over the past few years, companies running large data centres have become more and more concerned about both the cost and availability of energy.

In some cases, a scarcity of electricity supply is preventing enterprises from running their data centres at full capacity, and some local authorities are reluctant to grant consent for new data centre construction. 

In the UK, for example, it is reported that there will not be enough electricity available to support building new data centres within the M25 until after the 2012 Olympics. At the same time, of course, demands on businesses to store and process data continue to grow.

Happily, IT equipment in the past decade has become dramatically more power efficient per unit of processing power. But as computing capacity has increased, so too has the absolute energy used by IT equipment. A four-core server might be more power efficient per core than a single core, single processor box, for example, but in absolute terms it might still use more power than the older, less powerful equipment. 

Then there are the additional power demands that stem from the move to more compact form factors, such as rack-dense servers and blades, as well as larger and more powerful storage arrays and faster networks. The Department of Energy and Climate Change calculates that data centres use 3% of the UK’s energy. Unchecked, that proportion could double by 2020.

A lot can be achieved in data centre efficiency with simple techniques such as refreshing hardware and consolidating IT systems. But IT equipment accounts for only a part of the data centre’s infrastructure. IT directors looking to make a dramatic improvement in their energy use need to look at the overall overhead of running the data centre, especially at the power and cooling costs.

The precise power profile of individual data centres varies greatly with age, construction and even geographical location all affecting efficiency. But industry figures put IT power consumption – servers, storage and networking – at around 40% total energy. Cooling, meanwhile, consumes another 40%

Around 15% of power is lost as it circulates around the power infrastructure, and through equipment such as power strips and UPS (uninterruptible power supply) systems.

The remaining five to six per cent of data centre power goes on support systems such as building management, security, telecoms, lighting and even the administrators’ coffee maker. This cost of electricity needed to accommodate human workers in data centre environments has prompted some companies to move to “lights out” locations that are managed entirely remotely.

As these figures reveal, the energy footprint of the typical data centre is disparate and complex. To date, that complexity has prevented data centre managers from achieving a detailed view of energy consumption and also from managing that consumption as effectively as possible.

In this, there is yet another parallel with the electricity grid. Just as utility providers are experimenting with so-called Smart Grid initiatives – in which energy consumption and input is monitored in real time and managed dynamically – some of the same concepts, and in some cases the same technologies, are being discussed in a data centre context.

Lessons from the Grid 

The starting point for Smart Grid initiatives are smart meters, that provide more detailed measurement of power consumption than conventional meters, especially around the consumption over time. 

According to Simon Mingay, research vice president at Gartner, “smart meters are incredibly useful in the context of the data centre, to gain greater granularity of what is being consumed and by what.”

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