During power outages and other disturbances, data centers rely on uninterruptible power supply (UPS) systems to help ensure continued operations. While these systems are most often powered by lead-acid batteries, many operators are now turning to alternative battery technologies for specific advantages over lead-acid in performance, reliability, safety, lifetime cost, and climate impact.
This is a welcome development, particularly as data centers’ compute and power burdens increase due to 5G, edge computing, the Internet of Things, artificial intelligence, and machine learning. For example, Dell expects that future rack densities will far exceed those of today, which have already vastly grown. Since 2012, the amount of computing used for the largest AI training runs has expanded by more than 300,000 times, and the computer resources consumed by AI double every 100 days.
Power-dense alternative battery chemistries answer data centers’ ever-growing need to pack more power into less space. For example, nickel-zinc (NiZn) batteries have twice the power density of similarly-sized lead-acid batteries and can reduce the rack systems’ footprint in megawatt class installations by over 50 per cent, while delivering the same amount of power with less than a third of the weight. Such developments significantly reduce energy storage-related capital expenditure costs for data centers.
The need for sustainability and resilience
As cloud-based services and storage become central to business operations, data centers are under increasing pressure to ensure the resilience of their mission critical facilities. Through the use of alternative batteries in their UPS systems, data centers can improve the reliability of their operations.
For instance, battery string reliability is key to avoiding unplanned maintenance: when a lead-acid battery cell fails, it creates an open circuit that halts string operation. On the other hand, a depleted or weak NiZn cell remains conductive, which allows the string to continue operating.
“NiZn battery string reliability turns an emergency situation with other battery chemistries into a simple battery replacement at the next planned maintenance cycle with little cost and no operational impact, and so contributes significantly to improved data center uptime,” Tim Hysell, CEO and co-founder of nickel-zinc battery solution provider ZincFive Inc, says.
Data center operators may also pursue alternative batteries due to considerations of sustainability. Accurate, transparent reporting of emissions data is becoming a standard expectation across industries, including data centers. In addition to a data center operator’s internal emissions tracking and reporting, customers and partners that rely on these data centers also require access to this GHG emission data to incorporate it into their own reporting. Data centers are feeling pressure to not only operate sustainably, but also conduct comprehensive reporting to relay this information to stakeholders.
Using batteries as a carbon reduction tool
As data centers and their customers endeavor to meet growing expectations to disclose scope 3 emissions, they can use their UPS-related energy storage systems as an opportunity to establish a lower carbon footprint than their competitors. Energy storage is an increasingly significant part of a data center’s business operations, and the battery chemistry tied to a data center’s UPS offers significant trade-offs in the sustainability of their supply chain and environmental footprint. The battery chemistry used in their UPS systems can be measured, incorporated into goals, and seen as an opportunity to stand out.
However, despite numerous advantages, many alternative battery solutions have a catch. This issue is not inherent in the batteries themselves; it is that most existing UPS systems have already been designed to work with lead-acid batteries. Since each battery chemistry has its own charge/discharge profile, these UPS systems can often require additional hardware and re-engineering to accommodate non-lead-acid batteries. The time and cost needed for such modifications can prevent data centers and UPS manufacturers from making the switch and benefiting from more powerful, reliable, and sustainable batteries.
Fortunately, this dilemma has a solution. Drop-in replacement battery storage systems are becoming increasingly available, allowing alternative battery chemistries to be installed in existing UPS systems with no need for additional modifications. These battery cabinets adapt the data centers’ existing lead-acid charging system to the new battery by emulating the profile of lead-acid batteries to the UPS. Since the UPS does not know that the battery string now has a different chemistry, it operates the string as it did for its previous lead-acid inhabitants. This backward compatibility saves data centers time and money since they can integrate new battery types into traditional UPS systems without expensive modifications.
“The advantages of alternative batteries compared to lead-acid incumbents are numerous, including higher power density, superior reliability, lower costs, longer lifespan, and multiple environmental advantages that modern data centers need,” Hysell adds. “The challenge has been that most data centers were designed specifically to charge lead-acid batteries. However, new battery energy storage systems are allowing data center operators to easily integrate these alternative battery benefits into existing UPS systems with no need for hardware modifications. This can be the difference maker for many data centers who have been considering making the switch for years.”
When seeking more cost-effective and reliable configurations for their data center, facility managers are increasingly including alternative battery chemistries as part of their considerations. The right drop-in hardware can significantly impact the cost and effectiveness of a UPS system update. The right pairing of battery and cabinet can empower data centers to efficiently harness the benefits of alternative chemistries – no cost-intensive modifications needed.
