Green IT & Green Hosting

Energy Efficiency: Drastic Measures?

18/10/10

When it comes to energy efficiency in the data centre, it helps if you can distinguish PUE (power usage effectiveness) from DCiE (data centre infrastructure efficiency)

Why is energy efficiency so topical?

One reason is because the cost of power represents a very substantial part of any data centre budget. New regulation has introduced other factors into the energy efficiency debate, particularly reputational factors - witness the introduction of the CRC Energy Efficiency league table, which will measure relative performance between comparable organisations. 

There is a strong need to deal with power shortages, which some believe is fast becoming a looming spectre of real proportions where power cuts will become a reality. The other side of the debate is that, as data centres are mission-critical facilities, the carbon and energy efficiency issues may never predominate. Is it simply a price too high to pay to have an ultra-green and energy efficient data centre that does not deliver the reliability and service required of it?


World Landscape

Regulators worldwide have started to examine energy efficiency and metrics in relation to data centres. In the EU, the EU Data Centre Code of Conduct is a voluntary standard, but it has a quasi legal status as it is becoming a required badge for operators and participants in relation to public sector contracting. Other institutions - for example, financial institutions - are also beginning to mandate compliance with the code as a requirement of contract.

In the US and the UK formal energy efficiency regulations are either already in place or developing. These legislations include, in the UK, the carbon reduction commitment under the CRC Energy Efficiency Regulations 2010 (CRC). In the US, regulation is looming with the ASHRAE (American Society of Heating, Refrigeration and Air Conditioning Engineers) updating its standard prescribing
use of air conditioning systems components (Standard 90.1).

CRC has immediately created an issue for the data centre industry and the introduction of proposed new Standard 90.1, which for the first time covers computer rooms (and therefore data centres), has led to an open letter being signed by Digital Royalty Trust, Dupont Fabros, Amazon, Google, Nokia, Microsoft and IBM. A key point of the letter is that the standard is simply far too prescriptive and, instead of setting a required level of efficiency for a recording system, the cooling methods to be used are, in fact, prescribed. This does not effectively future-proof the standard and creates a significant headache for owners of existing centres.

The Common Standard - PUE

The data centre industries own standard, power usage effectiveness (PUE), currently remains the preferred global metric for measuring data centre efficiency. PUE measures the proportion of the power consumed by the IT equipment and compares this with the overall energy consumption of
the data centre. For new-build facilities, PUEs of between 1.3 and 1.2 are frequently heralded as being a major improvement. Existing data centres may have PUEs of between 1.6 and 2.0.

• Meaningful metrics should be measurable, achievable and comparable across similar sites. The advantages of PUE are:
• It offers a good comparison at the data centre level between the data centre power consumption and the IT load
• There is a benefit comparing data centres overall within certain tolerances
The metric also allows continuous comparison of the same data centre over a set period, as changes can easily be measured.
However, PUEs are perhaps still a rather blunt instrument and there are some disadvantages:
- PUE generally measures the whole data centre
- It is not a fully effective comparison between data centres, because of the variations in seasonal factors, such as atmospheric conditions.

Further, and perhaps most important, PUE does not distinguish between the technology used in the data centre. It is possible to have a low PUE simply because IT load equipment and data centre M&E are both inefficient. If both are equally inefficient, then the PUE is potentially quite low.

Effective Measure in Contracts 

There is clear evidence that technology is now starting to become marketed and sold with the express purpose of lowering PUE. Management on internal data centres and on third party colocation arrangements are also putting in targets to improve PUE and developing strategies to improve energy efficiency.

Although PUE is being used as an effective target, it is rare to see PUE as a binding service level in long-term data centre agreements, still less to see existing contracts varied. There are some merits in this because PUE was not designed as a hard contractual measure. If PUE is to work as a reliable data centre metric, then it must be combined with more efficient management of the governance of long-term contracts. Governance mechanisms are often underrated and underused in data centre contracts and there are considerable benefits of including detailed governance provisions in such contracts.

The whole point of measuring service levels in the data centre is to ensure the services do not fail; therefore softer governance measures, including mature dialogue on how to manage the centre proactively, are an essential component of an effective contract. Softer factors that governance should cover in a contract of this nature would include:
Proactive dialogue on technology improvements that reach all levels of the data centre stack, including M&E, and perhaps also reviews of efficiency or at least awareness for the service provider of what equipment is being run in its data centre space

• Training for supplier staff in relation to current good practice
• Development of professional standards in the data centre industry
• Grants for suppliers to bring technology innovations and improvements to the customer for review
• Continuous improvement programmes, including detailed gain-share mechanisms on power efficiency savings
• Encouraging the use of renewable energy resources.
Some of these issues are perhaps more commonly discussed between technical teams.

However, if energy efficiency is to claim its rightful place in the complex world of data centres, then energy efficiency measures must be included or formally considered as contractual measures.

A recent survey by Data Centre Dynamics Magazine (June/July 2010) indicates that the number of organisations measuring energy efficiency has increased substantially since 2008. There is clearly ample opportunity for well advised customers and suppliers to increase productivity gains substantially with intelligent contractual measures and improved governance mechanisms.

Mark Bailey is a partner at Speechly Bircham LLP, a top 50 law firm based in the City of London. For more information: www.speechlys.com

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