Power Usage Effectiveness (PUE) has become the de facto measure of data centre energy efficiency, comparing the total energy consumed by a data centre to the amount of energy that actually reaches the IT equipment.

However, the truth of the matter is that PUE is a very narrow metric. While it successfully addresses the power effectiveness of the data centre facility (power and cooling) it does not reveal anything about power effectiveness of the IT equipment within that facility (compute, storage and network).

To address this, The Green Grid launched its Data Center Maturity Model (DCMM) in 2011, which aims to give a holistic view of data centre sustainability and help organisations benchmark performance, determine levels of maturity, and identify ongoing steps and innovations to achieve greater energy efficiency in the future.

On the facility side, DCMM breaks the data centre down into four categories: power, cooling, management and “other”. Each of these categories is further broken down into sections, and data centre operators can score themselves in each category according to a range of criteria.

Similarly, on the IT side, DCMM breaks the data centre down into compute, storage, network and “other”. Scores range from 0 to 5, 0 being “minimal/no progress”, 2 being “best practice”, and 5 being “visionary”.

Operators not only fill in what they have achieved, but also their organisational targets. Based on the data entered, the DCMM tool also calculates a theoretical maximum level for each category, to help show organisations what they can realistically aim for.

All of this information can then be used to generate a “graphic equaliser” view of the data centre’s current maturity level, providing a visual representation of which areas of the data centre can be adjusted and improved:

Speaking at The Green Grid EMEA Forum in Brussels this week, Lex Coors, chief engineering officer at Interxion and member of The Green Grid's advisory council, said that the DCMM has value for both the C-suite and the operations perspective.

For the C-suite, it generates an overview of the organisation's current data centre maturity level, and puts future aspirations for energy efficiency and sustainability into context.

“If I gave my engineers a free hand in the data centre, they would design a 10,000m² facility with only one rack,” said Coors. “DCMM allows the C-suite to take the lead and decide how they want to position themselves from a sustainability point of view.”

It can also be a useful resource for data centre operators to explain to the C-suite where investment needs to be made to improve the overall sustainability of the facility. For example, if the data centre scores a level 3 for cooling and power, but only a level 1 for server efficiency, it might be worth investing in new servers.

“If you go to finance and say you want to change some of my equipment for a better model they won't understand why. But with a tool that clearly identifies the steps and different angles of advantage, they may be persuaded to give you the money,” said Coors.

From an operations perspective, DCMM creates a clear road map to improve energy efficiency and sustainability through benchmarking. Organisations can use the DCMM online tool to upload their data and compare their efficiency with other similar facilities.

It also helps engineers to design and upgrade their facilities with sustainability in mind from the offset, meaning that they can make informed choices about procurement and spend money wisely.

Last year, for example, online auction site eBay used The Green Grid's DCMM to guide the design and construction of its enormous data centre in Arizona. Despite being in the middle of the desert, the facility was able to slash costs and maximise energy efficiency, achieving a PUE rating of 1.35.

Coors said that the DCMM is the first tool that combines facility and IT to give a holistic view of data centre efficiency. However, users can just use part of the model if they choose to do so.

“As a colocator, I have an understanding of facility but I do not have much knowledge about IT. It doesn't matter because now my customers can use it if they want to, or I can just fill in the facilities side if I don't have other people to fill it in on the IT side,” he said.

“If you are a corporate company, both fill in their part and suddenly you have one overview instead of two overviews. It seamlessly comes together.”

Coors admitted that many data centre operators have been put off from using the DCMM, because of the initial complexity. However, in April The Green Grid launched an online tool to make the process much simpler, and allow data centre operators to measure efficiency against benchmarks.

Operators can choose whether to fill in the “summary” version, which takes 20 minutes for the facilities portion and 20 minutes for the IT portion, or the more detailed version that gives a more granular breakdown of all the different elements.

Speaking to Techworld at the EMEA Forum, Mark Schiller, Executive Director of The Green Grid, said that companies are looking for ways to measure more of the resource use life cycle – not just PUE.

“We think that the data centre maturity model provides a really nice tool for companies to look at the big picture,” he said.

“We're starting to build a library of companies that have taken their data centres and used the tool to enter the data. You can identify a set of characteristics in your data centre and look for good comparisons from other data centres that are in the database.”

Schiller said there are currently around 100 entries in the database, but some organisations use the tool without committing their data, so it's hard for The Green Grid to know how many are using it overall.

“We strongly encourage companies to commit their data to the tool either anonymously or in a way that's attributed to them, because from a benchmarking perspective it really adds value to the tool,” he said.

“We see it as an industry resource that we want everybody to be able to benefit from, just as they have from other metrics like PUE, CUE (Carbon Usage Effectiveness) and WUE (Water Usage Effectiveness) and so forth.”

Schiller said that these other metrics still have value in their own right, and The Green Grid expects organisations to continue using them to monitor individual aspects of the data centre discreetly, depending on time constraints.

“We think there are many valid approaches to improving those numbers, either in concert or separately. We mostly want to provide the tools so companies have the ability to incrementally improve those areas as makes sense for their business,” he concluded.