Green data centers: Identifying truly energy-efficient data centers

Energy-efficient data centers reduce facility costs and help protect the environment, but many data centers are fabricating truths about being green.

Energy-efficient data center facilities are important. But plenty of data centers base their green credentials...

on promises that cannot be fully supported or statements that are too glib to be true.

People increasingly perceive data centers as energy hogs, prompting technology vendors to position their products as sustainably made or "green." Even large data center owners are claiming to have green facilities, yet some of these promotions should probably be taken with a large dose of cynicism.

Carbon-neutral data centers

The biggest claim that IT equipment vendors and green data centers make is that all items are carbon neutral: Supposedly, the overall amount of carbon used in the creation or operation of an item is offset in some way. In essence, the same amount of carbon released through owning or using the device is being trapped through other means that are under the control of the vendor or operator.

The main way to reach carbon neutrality is through planting trees -- which is good, but is it all as it appears to be? What possible carbon output is really being measured? If it is the total amount of carbon used in the manufacture of any piece of IT equipment, then it is doubtful that this is being offset completely. IT equipment is made from a variety of materials, ranging from petro-chemicals to rare metals and silicon. Acquiring the raw materials for each of these is not particularly carbon efficient, and it is doubtful if anyone could carry out the necessary modeling to calculate how much carbon has been used in procuring the raw materials for a single server or network switch.

So, let's be a little looser with the definition and just look at the carbon used in operating IT equipment. Then this just comes down to a simple calculation of energy usage by the equipment, right? Yes -- and no. Energy usage within the equipment itself is just one part of the equation -- there is also the other equipment that is dependent on the item or that which the item itself depends on. So a 150W server running in a data center with a power usage effectiveness (PUE) of 2 would require a carbon offset of at least 300W.

However, as more IT functionality creeps outside of the on-premises data center, how about the proportion of energy that the organization's other, cloud-based data centers use?  What about the energy the servers and systems running the Internet consume? And what about the bring your own device movement that has employees using data center energy as well?

Then there is the carbon offset side of things. If this is based on planting trees, does it consider the age of the tree for the amount of carbon it can produce or leave when it dies? Does it take into account the failure rate of newly planted trees? It's 70%. Clearly, carbon offsets are fraught with issues.

Data centers using renewable energy

There is also the claim that a facility is powered by renewable energy. In some cases, this is demonstrably true. There are data centers built in countries, such as Iceland, where the vast majority of energy is provided from hydro or thermal sources and is, therefore, renewably generated.

Some facilities are built right next to specific hydro or other renewable energy sources (such as many in Colorado) and only tap into the grid energy network should there be problems with the main renewable source.

But for the majority of so-called green data centers, the energy contract is with a company that invests in renewable energy -- but that does not mean the energy a facility gets comes from those investments. For example, in the U.K., the vast majority of energy comes from the National Grid, and a specific electron cannot be forced to a specific place from any particular generator. Therefore, although a facility owner may be paying on a renewables contract, the energy can come from nuclear, coal, gas or oil just as well as it could be from wind, hydro, solar or any other green system. In fact, less than 10% of the U.K.'s overall energy is provided via renewable means. So, there is a 90% chance that the power is not coming from renewable sources.

In one case in the U.S., a data center facility boasted of its green credentials through a contract with a local wind farm. The wind farm was built to provide more than 300,000 homes with energy, but the data center took most of this. The homes could no longer be viewed as green -- as was the idea -- unless the companies were double-accounting for the energy.

Finally, there are PUE claims. On its own, the PUE indicator is easily manipulated. PUE is a measure of the proportion of energy used in powering a data center facility against how much is used to power IT equipment. A facility where peripherals use 1 watt of energy to every 1 watt used at the server has a PUE of 2. This shows 2 watts of data center power against 1 watt of IT equipment power.

In theory, a data center with a PUE of 1.5 is more energy efficient than one with a PUE of 2. However, what happens if you virtualize all the IT servers so that 80% of existing servers can be turned off, but do not change the peripheral equipment operations? The overall IT equipment wattage drops by 80%, but the peripheral wattage stays the same. There is now an IT platform that is far more utilized and energy efficient, but the PUE has risen appreciably -- which has to be wrong.

Don't fall for greenwashing. Make sure that green claims are provable and that you can stand by them.

About the author:

Clive Longbottom is the co-founder and service director of IT research and analysis firm Quocirca, based in the U.K. Longbottom has more than 15 years of experience in the field. With a background in chemical engineering, he's worked on automation, control of hazardous substances, document management and knowledge management projects.

This was first published in December 2013

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