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Saving money through an energy-efficient UPS

The simple decision to install a more energy-efficient UPS can bring about a high return on investment.

A data center is a power hog. Unfortunately, energy prices have been trending ever higher, and the cost of powering a data center is now a major drain on an organization's budget. 

Beyond this, many countries are heading toward an energy deficit in the near future; for example, it has been predicted the United Kingdom will not have enough power-generation capability by 2015 to keep everything going if any part of the national grid and generation capability is out of service for any period of time. Governments also see energy usage by large organizations as being a suitable target for taxation -- carbon taxes are already in place in countries such as Australia and the U.K., and data centers are a soft target for tax revenue gains for cash-strapped governments.

As organizations become more knowledgeable about this, they are focusing on being more efficient with power use within the data center. More modern equipment, application rationalization, virtualization, consolidation and cloud computing are all helping to improve the overall workload/power ratio.

However, one piece of equipment that has remained hidden is the uninterruptable power supply (UPS). Historically, the idea was to have a single piece of UPS equipment that could power the whole data center facility for the few minutes required between a break in grid power and auxiliary generators taking over. This was fine when the majority of a data center's power requirements were measured in kilowatts, but now, many data centers are well into the megawatt power levels.

Dependence on a single UPS means that there is no flexibility. If the growth of the data center means that the existing UPS can no longer meet power needs, then your data center will either need to have another -- often identical -- UPS installed alongside it or a complete replacement.

Such dependence also counts against high availability. If the worst happens, and there is a power failure coupled with a UPS failure, the whole facility is out of action until the auxiliary generators start up and everything can be restarted. The company faces the loss of data and transactional contextuality associated with that failure.

But the worst aspect of an older UPS is that it's not energy efficient. Many are only between 90% and 95% energy efficient -- which sounds good until you look at the figures. Let's assume a 1 megawatt data center facility where every last watt of that energy is going through the UPS -- and 10% of it is being lost. Of the close to 9,000 megawatts/h per annum of energy brought in from the main grid (and paid for), 900 megawatts/h is being wasted. Even if it's running at 95% efficiency, there is still 450 megawatts/h going to waste.

A modern, energy-efficient UPS can run at greater than 98% efficiency and is far more modular in its construction. As a data center grows, more modules can be added to meet incremental needs with automatic workload balancing. Such a modular approach also allows for greater availability: If a module does fail for any reason, then the other modules can take over and still maintain overall power to the facility.

Another aspect of availability is the active role that an energy efficient UPS can play in dealing with artifacts in a grid power feed. During voltage spikes and under-voltage situations, radio frequency interference (RFI) and other problems with the feed can be handled through the power cleansing capabilities of the UPS. They ensure that equipment in the facility is provided with a fully managed, clean power feed.

Better battery capabilities and life means that modern UPSes can also run for longer. As most grid failures are essentially transitory, you may not need to switch on auxiliary generators as often. Workload prioritization is available, with lower priority workloads being elegantly shut down through the UPS and only a portion of the data center kept running through power via the generators.

But the main thing as far as the business is concerned will be the energy savings that a more modern, more energy-efficient UPS brings to the fore. Saving 3% to 8% on the overall data center energy bill for a one-off capital outlay with a high return on investment should be a simple decision. The best part of this investment is that it keeps on giving; every incremental improvement in energy efficiency within the data center then has this extra 3% to 8% payback on top of it.

The UPS has long been a hidden secret within the data center. It is now time to bring it out from the shadows and acknowledge its importance in helping an organization manage its data center energy usage.

Quocirca has written a report on the subject of UPSes that is available for free download here.

Clive Longbottom is the co-founder and service director at Quocirca and has been an ITC industry analyst for more than 15 years. Trained as a chemical engineer, he worked on anti-cancer drugs, car catalysts and fuel cells before moving into IT. He has worked on many office automation projects, as well as control of substances hazardous to health, document management and knowledge management projects.

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