Critical power thinking is needed for 24/7 reliability

For datacenters, few things rival the importance of ensuring service reliability around the clock. Without this consistency, the day-to-day operations of countless critical sectors — from telecommunications to emergency medical services — can be severely disrupted, risking individu- als’ safety and hampering economic growth.

This underlines why datacenters are cautious about protecting their assets, and why choosing the right UPS system is particularly important.

To ensure that these systems can support the datacenter’s needs at any time, they require the best battery technology to power them.

Lead acid batteries have a long history as the default choice, but the proliferation of new innovations and technologies has started to change this in recent years.

Datacenter operators have the option of choosing between a variety of battery chemistries, each of which comes with unique advantages.

When analyzing what battery type is best for their datacenter workflow, managers should keep in mind these key components.

Higinbotham has a strong track record of successfully growing advanced materials companies in the energy storage, semiconductor, and solar markets.

He worked as executive VP/GM for ATMI and led the rapid growth of the company, which was sold for more than $1 billion.

He was formerly the CEO of PowerGenix, the company that pioneered the novel nickel-zinc battery technology that has become the core of ZincFive’s portfolio.

Physical Footprint

The physical size of a UPS system plays a significant role in the layout and internal organization of datacenters.

Out of the commercial battery varieties, lead acid has the largest footprint: it possesses the lowest power density, and therefore requires significantly more space than lithium ion or nickel zinc (NiZn) technology to accommodate the same amount of storage.

While this doesn’t pose a challenge for every facility, it does mean that lead acid batteries are poorly suited for modular facilities, as well as for datacenters in expensive urban areas.

In comparison, NiZn batteries use up to 65% less linear footprint and thus allow modular builders and construction teams to better optimize their buildouts.

Total cost

Cost inevitably plays a decisive role in selecting the right battery type. It’s important for datacenter managers to factor both capital expenditures and long-term operational costs into their investment decision.

Lead acid batteries have the distinct advantage of being the lowest upfront-cost option on the market. They do, however, require regular maintenance to preserve their average five-year lifespan.

Though an attractive option because of their low initial capital cost, lead acid batteries can be the most expensive to operate in the long run — an important consideration for datacenter managers.

However, lithium ion and NiZn batteries have a higher upfront cost but have a longer life and require less maintenance once installed.

For example, by lowering operating expenses (OpEx), NiZn solutions reduce ownership costs by up to 28% over lead acid-based UPS products across the total UPS useful life.

Sustainability

The environmental impact of datacenters has gained increasing attention in recent years as businesses face growing pressures from investors, consumers, and regulatory agencies to integrate sustainability into their operations.

A third-party expert analysis was conducted to assess the sustainabil- ity of various battery chemistries.

The study compared factors such as GHG emissions, water footprint, energy use footprint, and volatile organic compounds. The study also provides GHG Protocol Scope 3 level emissions analysis (a methodology that can be used to account for and report emissions from companies of all sectors).

This information helps datacenter operators make sustainability one of the top factors in picking a technology — the best choice for both the environment and their company’s reputation.

Reliability

Unfortunately, the very UPS system meant to prevent an outage too often causes one; accounting for 37% of datacenter outages, on-site power failure is still the most common cause of significant datacenter outages. The majority of these onsite outages (53%) are caused by UPS failure and often may cost over $100,000 to repair.

One distinct reliability advantage is the ability to sustain battery discharge despite failure of an individual battery cell.

In a UPS system, individual batteries are connected in a serial string (with multiple strings often paralleled) to support the required system voltage, power output, and run time. When a lead acid or lithium ion cell fails, it creates a high impedance or an open circuit that halts battery string operation. One single cell could be the difference between having the backup capacity needed or none at all, leaving the datacenter at unnecessary risk.

Unlike lead acid and lithium ion, NiZn cells remain conductive when weak or depleted, allowing for continuous string operation and uninterrupted uptime.

Safety

The safety of datacenter workers and equipment is paramount when choosing batteries. Selecting a battery type that’s inherently non-flammable removes significant risks and makes the datacenter safer.

For example, cell-level testing with the UL 9540A test method has revealed that NiZn batteries do not exhibit thermal runaway and are non-flammable, making them a safer choice for datacenters and their workers alike.

Whichever battery type they choose, datacenter operators can help ensure their batteries’ safety by having them adhere to the National Fire Protection Association (NFPA) 1 (National Fire Code), the NFPA 855 standard, and the International Code Council’s (ICC) International Fire Code (IFC) 2021. These standards list both the installation safety rules for energy storage systems and testing procedures for batteries.

Additional Resources

As the number of options on the market grows, choosing the storage technology best suited for your datacenter has major impacts on cost, energy efficiency, sustainability, and safety. That’s why the Institute of Electrical and Electronics Engineers’ (IEEE’s) 1679 document family helps users, integrators, and servicing organizations compare traditional stationary battery technologies with newer, advanced technologies.

These documents guide the user to select the best battery type for their needs.

If you are considering an energy storage purchase, the IEEE 1679-2020 document and its child documents (IEEE 1679.1, 1679.2, 1679.3 and 1679.4) are invaluable tools.