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How batteries can assist data centres in overcoming power grid instability

Michael Sagar

Michael Sagar

Senior Strategic Marketing Manager, Data Centres & EMEA, EnerSys
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Batteries in a data centre UPS application

Michael Sagar, Senior Strategic Marketing Manager, Data Centres & EMEA, EnerSys, describes the benefits that modern TPPL batteries have versus more commonplace VRLA UPSs. 

Human beings are more connected than ever, with data centres playing a pivotal role in storing our data and making it accessible. A report from IDC (Data Age 2025) highlights global trends in this regard. It predicts that 6 billion connected users will access a data centre almost 5,000 times per day by 2025. By that time, we will be generating 275 ZB of data annually as a global society.

At the same time, our global energy consumption is raising concerns. Users are striving to reduce their carbon footprint and operate in more sustainable ways. Data centres are no exception as they already consume between 1-1.5% of global energy, and the demand for data storage is growing. Reducing consumption and improving energy efficiency is therefore vital for data centre operators to meet their regulatory requirements and fulfill their social responsibilities.

However, data centre uptime is also a critical performance indicator. Energy solutions, including backup power, must enable data centres to meet customer expectations without excessive power consumption. The Uptime Institute’s 2020 Global Annual Data Survey shows that this is not easy to achieve, with 78% of data centres experiencing an outage in the past three years, of which the most common cause is a power failure.

Trends affecting data centre energy consumption 

Data centres rely on Uninterruptible Power Supplies (UPS) for backup power during an outage. They provide a window of autonomy to allow generators to come online, or for an orderly shutdown of the system. In the past, generators would take 10 to 15 minutes to bring online, but modern technology enables automatic or remote startup. These advances mean that UPSs need to only cover the shortfall for around five minutes before backup generation comes online. 

A significant portion of a data centre’s energy consumption is for cooling supplied by air conditioners. Cooling keeps the electronic equipment like servers and UPS batteries in an acceptable operating range. However, advances in technology allow the batteries to operate at elevated ambient temperatures.

Changes in UPS battery technology

Flooded lead-acid batteries were commonly used in the early days of data centres. The technology does, however, have some drawbacks. For instance, the batteries needed significant maintenance, including regular topping up with water. It also means that relatively high levels of gas are generated, which require ventilation.

The introduction of VRLA (valve-regulated lead-acid) batteries achieved benefits over flooded technology by immobilising the electrolyte in a gel or absorbent glass mat (AGM) material. This eliminated the need for topping-up with water and reduced the gas emissions. AGM-based VRLA batteries are now common in data centres because of the lower maintenance and reduced ventilation requirements.

Thin Plate Pure Lead (TPPL) technology offers further advances compared to standard AGM VLRA batteries. The plates are formed from very high purity thinner grids, which results in a greater contact area between the plate and the electrolyte.

The advantages of TPPL battery technology

TPPL batteries have a higher power density than AGM VLRA batteries. The effect comes from stacking more of the thinner plates into the same volume. As a result, TPPL batteries take up less space, normally being at least 20% smaller than their standard VRLA equivalents. This is a significant advantage for data centres as it frees up space for additional servers.

High power density also helps TPPL batteries to charge quickly. They can deal with larger current peaks and have a higher charge acceptance than other lead-acid technologies. A short charging time means that batteries are ready to respond to the next disturbance quickly and can, therefore, handle multiple outages in succession. TPPL batteries also have low self-discharge characteristics. They can be stored at 20°C (68°F) for up to two years without needing a refresh charge.

Battery life is a significant contributor to the total cost of ownership (TCO) of UPS solutions for data centres. Every battery has a finite life, after which it must be replaced. However, TPPL batteries have a proven lifespan of eight to 10+ years, which is typically 25% longer than VRLA batteries. In addition, TPPL technology is robust in terms of tolerating higher ambient temperatures, allowing data centres to reduce cooling and save on energy. Higher temperatures reduce battery life, so lowering energy costs should be weighed against the cost of more frequent battery replacement.

Summary

Data centres are playing a more vital role in the global community due to the high volume of data we generate, as well as the need for continuous access to this data. Recent increases in remote work due to the pandemic also contribute to this trend towards data centre growth.

Power grid instability is a serious threat to data centre online time but increases in power demand only add to the pressure on the grid. It is crucial for data centres to have reliable backup power in the form of a UPS complemented with high-performance battery technology. Lead-acid batteries have supported backup applications in data centres for decades, and TPPL technology builds on that foundation. This advanced battery technology delivers improved performance for the demanding environment of data centres.

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