The uninterruptible power supply system provides two functions: one is continuous power regulation for IT loads, and the other is to provide short-term power to compensate for this gap when emergency generators are online after utility power supply interruption.
In the context of data centers operating as bidirectional microgrids, two key issues have arisen. Which battery technologies are most suitable as battery energy storage systems, and what are their sustainability proofs?
For grid interaction, the battery energy storage system consists of three main components:
● Battery management system
●Energy Management System
● Power conversion system
The data center department traditionally uses lead-acid batteries and static UPS systems, but this situation is gradually changing. It is expected that by 2025, lithium-ion batteries will account for 38.5% of data center energy storage. According to reports, its increasing popularity is due to its durability and smaller footprint. Compared to traditional lead-acid batteries, lithium-ion batteries require ten times more recycling times. Although traditional lead-acid batteries are cheaper, they require more frequent replacement and are larger in size and heavier in weight.
However, in terms of sustainability in the data center industry, this is not a direct competition between lithium-ion and lead-acid. Throughout the entire lifecycle of lithium, there are challenges in using it, from the extraction that requires a large amount of water to the limitations of recycling. In contrast, lead-acid batteries benefit from a long-term established recycling supply chain and can recycle over 98% of their components.
Next, let’s explore the main factors that affect current decisions related to battery energy storage technology, as well as important sustainability indicators that should be considered. It checks the following battery types:
●Lead acid
●Sodium sulfide
●Sodium nickel chloride
●Nickel cadmium
●Vanadium redox flow battery
●Zinc bromide flow battery
● Lithium ion
Logically speaking, emerging battery types that can be considered viable alternatives to lithium-ion include technologies such as vanadium redox flow batteries, metal air batteries, and sodium sulfur batteries.
Given the advantages of liquid metal batteries in terms of early system costs, operating costs, cycle life, response time, footprint, and geographic dependence, liquid metal batteries seem to be a potential game changer for various UPS types.
New pressures and regulatory concerns make battery selection increasingly important
Streamlining energy and carbon reporting, corporate sustainability reporting directives, and energy efficiency directives will force data center companies to report their sustainability efforts, including battery selection.
Important factors include energy density, which refers to the amount of energy available for storage in a specific area, volume, or mass. This, together with power density and the correct battery type, determines the most suitable battery technology to optimize the selection of the system.
It should be noted that other energy storage options are also available, which may be suitable for the power needs of data centers. This includes power flywheels, compressed gas storage, as well as potential pumped storage, tidal flow, and gravity storage.
Sustainable battery selection criteria for battery energy storage systems
When choosing a suitable battery energy storage system, many interacting factors should be considered. This includes application types, sustainability performance indicators, investment and return on investment opportunities, technological performance, and location factors. The key is to consider the environmental impact of battery technology from the perspective of the entire lifecycle.