The need for ever more powerful processing and greater volumes of storage mean that the data centre consumes significant amounts of electricity, and skyrocketing energy prices have resulted in increased expenses at a time when budgets are tight and cost optimisation is crucial. Reducing energy consumption in the data centre has thus become top of the agenda for many organisations. Typical initiatives in this regard include introducing more efficient lighting, cooling and hard drives, all of which can be beneficial.
However, an area that contributes significantly to power consumption, but one that is often overlooked, is the efficiency of Uninterrupted Power Supply (UPS) solutions. UPS are vital in the modern data centre, but can also contribute to increased energy costs if they are not running at maximum efficiency at all times. Addressing this area can lead not only to significant savings but will also provide optimal protection in the event of a power outage - the main function for which a UPS is installed.
Data centres have become central to the operations of many businesses today, and the growing requirement for virtualisation, cloud services and data availability on the go have only added to the critical nature of data centres. Constant uptime is a necessity, which has made the implementation of UPS solutions vital in the data centre, and although these are generally a grudge purchase, the risk of not having emergency backup in the event of a power outage far outweighs the initial purchase price and the on-going running costs.
However, many legacy data centres were not designed with the requirement for UPS in mind, and adding these solutions in after the fact can have an adverse effect on overall energy consumption, particularly if attention is not paid to the efficiency of the UPS itself. Even data centres designed with UPS in mind need to take into account the overall efficiency of the UPS, as this can have a significant impact on energy consumption.
The efficiency rating of a UPS is expressed as a percentage, which indicates how much of the original incoming power is used to power a data centre's critical load, versus how much is lost in the operation of the UPS.
For example, a UPS that is 96% efficient passes 96% of the incoming power to the load, while a 94% efficient UPS passes 94% of the input power to the output. This also means that 4-6% of the power, respectively, represents losses, or wasted operating costs. This rating is also typically the efficiency at 90-100% load capacity, meaning that lower capacities, the UPS will be less efficient, using more power to function and thus costing more to run.
In addition, some UPS solutions will give their efficiency rating based on inadvisable practices such as running the UPS in static bypass or eco-mode - this means that the UPS is not online at all times, and in the event of a power emergency can take time albeit milliseconds to transfer to UPS mode, which typically negates the entire purpose of having a UPS in a data centre environment.
An energy efficient UPS solution can typically deliver up to 4% energy savings per annum. In a data centre environment that runs 24x7x365 this saving can be significant. For a modest 100kVa UPS, this equates to 4000 watts per hour, or four kilowatt-hours. One kilowatt-hour costs around R1.50 in today's prices, so four kilowatt-hours cost R6. If you multiple this saving for 24 hours a day, it totals R144 a day. Multiply this saving by 365 days a year and the total saving comes to R52 560.
Organisations can thus save over a quarter of a million Rand over five years just by using efficient UPS technology. Many large data centres will have larger UPS solutions, and multiple devices, meaning that these savings are multiplied in proportion, and with the energy price continuing to rise year on year savings will increase in line with this. In addition, more efficient UPS systems use generate less heat, so require less cooling, and can thus contribute to overall lower energy consumption of the data centre in other ways as well.
The efficiency of a UPS is an important consideration, as it will affect the on-going cost of running the device. Companies need to consider the Total Cost of Ownership (TCO) of a UPS, as the original purchase price that might have initially been highly competitive may pale in comparison when considering the costs of a UPS that runs at a lower efficiency. Organisations need to implement a UPS solution that is at least 96% efficient in true online double conversion mode at both low and high load capacity, delivered by a partner that has a proven track record in the market and the ability to provide high levels of local service. This will ensure the best balance of cost effectiveness, efficiency and power protection for the critical data centre environment.
