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How Data Centres can Reduce Electricity Consumption

How Data Centres can Reduce Electricity Consumption



By Louis McGarry, Sales & Marketing Director, Centiel UK


The escalating cost of power is headline news. According to the Office of National Statistics: in the UK, electricity prices rose by 54.0% and gas prices by 95.7% in the 12 months to August 2022. For data centres, particularly those operating inefficient legacy UPS systems, now is the time to review the management of technology and see what changes can be made to reduce power consumption.

Within the data centre, there are a variety of culprits burning electricity. For example the load itself, environmental controls (air conditioning) and UPS systems. However, how systems are managed can have a significant impact on reducing electricity usage.


Location, location, location

If the UPS and batteries are located together, more air conditioning will be required. A UPS can continue to run optimally at fairly high temperatures of up to 400C without derating. VRLA batteries, on the other hand, need to be kept at around 200C to maintain optimal functionality. Simply locating the batteries away from any heat source in their own dedicated environment, will result in a reduction in cooling requirements or may allow you to remove cooling completely. 

If it is not possible to separate the batteries from the UPS, consideration could be given to using Li-ion batteries which require less space and can run optimally at much higher temperatures. 


Understand right sizing

We speak a lot about right-sizing UPS systems according to the actual load, particularly when replacing legacy systems. It is extremely common to see UPS oversized and underutilised. Generally, this relates to large standalone systems, but it can also occur with modular systems too. Regardless of the topology, if a system isn’t designed based on actual load, organisations could be paying more than they need to. If a UPS system is oversized, it doesn’t automatically mean it has to be replaced, there are other things that can be done to hit the sweet spot of efficiency. For example, you may have multiple UPS supporting a much smaller load than intended at the design stage, switching off the amount of UPS that isn’t required will have a positive effect on efficiency and save money. There is often nervousness around switching off systems, however, as long as the required resilience level is maintained the positives outweigh the negatives.


Know your modes

To enhance efficiency, some data centres with a resilience level of N+N and above, manage their UPS systems by utilising both economy (eco) mode and true online double conversion (inverter) mode. It may be the case that the A feed (N) will be fed via the inverter and the B feed will run in eco mode. The latest technology offers 97.1% efficiency in normal operation, switching to eco will increase to 99%, allowing the data centre to save circa 2% in losses. Over time this will offer savings, and for anyone running legacy systems with efficiencies as low as 85%, the savings are much greater. Sometimes this can be perceived as a risk as the eco mode is effectively raw mains, but if the mains goes out of tolerance the transfer back to the inverter is instantaneous and seamless. This is a good option for data centres with a minimum resilience level of N+N. 

Other modes are also available for data centres that install True Modular UPS. These systems are designed with intelligent technology that uses as many modules as needed to match the load demand. This Maximum Efficiency Management (MEM) mode looks for the most optimised energy-efficient point of the overall system and uses active-sleep modules to ensure the system is always operating at its maximum efficiency. Put simply, as the load decreases modules hibernate and, when the load increases, the modules become instantly available while maintaining the required resilience. With legacy or oversized systems, optimum efficiencies are generally at the upper end of the system’s capacity, so when underutilised, they waste energy and can have a significant impact on OpEX.


Time to review

Knowing that legacy systems cost more to run, consideration must be given to the fact that it could be more cost-effective in the long term to refresh the equipment with more modern technology. When installing a rightsized, true modular UPS system, we have seen the equipment pay for itself within three to five years based on efficiency alone. This is before you factor in the impact of the dramatic rises in electricity costs that we are currently experiencing. It costs nothing to have a full review of existing technology and to make such calculations. 

The challenge when it comes to purchasing any new equipment is that marketing tends to be as clever as it is confusing! A UPS may be advertised as 99% efficient with an asterisk and an indication in the small print that this refers to eco mode. As mentioned above, this essentially means when on raw mains! To make a true assessment of the efficiency of a UPS, it is important to understand its efficiency in true online double conversion mode. 


Active management

There are numerous ways to make an immediate impact on reducing power usage. However, the key to maximising efficiency within data centres over the long term is to ‘get under the hood’. You need to understand load profiles and get to know your UPS. 

The UPS will continually generate data about the supply, power usage and environment. Live, real-time information can be used to make tweaks and changes. For example, has the load profile changed over time? Or does the load fluctuate on a regular basis? How old are the systems and what efficiency levels are they running at? The data provided by the UPS is essential for decision-making. 

UPS manufacturers can help by working with data centres and assisting them in planning how to maximise efficiency. The information about the true performance of any UPS is readily available and experienced manufacturers can use this to help clients to optimise their USP systems. 

However, I believe optimal efficiency can only be achieved with open discussion and collaboration with those that design and develop the kit. You just can’t buy a UPS from a brochure or a website. It is necessary to engage and talk, to develop a logical and appropriate approach to UPS management to ensure nothing is missed. Getting the right advice and learning how to harvest the information from UPS means that informed decisions can be made. The overall result is that savings can be made on energy and operating costs. 


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