Green IT : Today’s planning for tomorrow
Time to think about Green IT....but there are so many conflicting reports!
Apparently a major hardware vendor recently did a study that showed the IT industry generates more carbon than the airline industry - a cause for concern!
Another asserted ‘For every server you take out, you're removing one and half tons of emissions per year.’
Earth Hour in March 2011 had companies making extravagant claims about how they were making sure that they switched off as much power as possible during the designated hour (conveniently positioned at 8pm on a Saturday night, hardly peak operating time for business!).
But according to another vendor: "It's rarely a requirement on a bid. The typical ones are there: processing power, memory, storage and so on, but there are never questions about power requirements, recycling and re-use.”
And according to a recent e-skills report Technology Insights 2011 from the Sector Skills Council for Business and Information Technology www.e-skills.com, Green IT is classified as a ‘developing issue’, quote “where ‘developing’ does not necessarily mean new – some of these issues have been around for some time, for example green IT and the transformation of businesses using IT, but it can take time for the impact to be felt.” Timescale 4 to 7 years!
The reality is that there are economic advantages to reducing power consumption. Apart from the direct lower electricity usage from using lower powered devices, there is a knock-on effect due to less cooling being needed.
But for the non-technically initiated, it is not always just a matter of reading the label, power factor correction and efficiency must be taken into account. Before computing and storage devices can use electrical power, the AC provided from the source must be transformed to direct current (DC) by a power supply. The term power indicates the rate at which the electricity does work, such as running a central processing unit (CPU) or turning a cooling fan. The power that the electricity provides (apparent power) is simply the voltage times the current, measured in volt-amperes (VA).
There is a difference between the power supplied to a device and the power actually used by the device because the capacitive and inductive nature of AC circuits will change the phase relationship of current and voltage. The true power, measured in watts rather than VA, can only be delivered when the current and voltage overlap.
The power factor (PF) of a device is a number between zero and one that represents the ratio between the real power in watts and the apparent power in VA. A power supply that has a PF of 1.0 indicates that the voltage and current peak together (the voltage and current sine waves are always the same polarity), which means that the VA and watt values are the same. A device with a Power Factor of 0.5 would have a watt value that is half the VA value; for example, a 400VA input device with a Power Factor of 0.5 would be a 200W output device.
A common misconception is that the power factor and the power supply efficiency are related, but this is not the true. Power supply efficiency is the ratio of output power in watts to input power in watts at peak efficiency. For example, a typical white box power supply with a peak efficiency of 75 percent would waste at least 25 percent of the incoming energy by converting it to heat that must then be dissipated.
Devices with a low power factor, on the other hand, do not waste energy. Unused energy is simply returned to the utility and is not paid for by the customer. Utilities charge for true power used as measured in kWhours, not in VA. The main costs associated with a low power factor are for higher amperage circuits to deliver the same amount of true power as a device with a power factor closer to one.
Power supplies for servers usually contain circuitry to correct the power factor (that is, to bring input current and voltage into phase). Power-factor correction allows the input current to continuously flow, reduces the peak input current, and reduces energy loss in the power supply, thus improving its unity (~1), which allows smaller circuits to be used. Using energy-efficient PFC devices, including UPSs, can lead to significant cost savings for data centres where the incoming feeds are measured in megawatts.
If this is all a bit much to take in, there are some simple actions to be taken, helping you to claim to be a ‘Green IT Aware’ company.
- Add ‘Green’ to your Mission Statement, and adopt a policy of always opting for a green solution where possible.
- Use a ‘Green IT Aware’ company for your support needs – Support Tree is well qualified in this regard, and can advise on hardware and software choices, and a roadmap to a greener environment.
