Sustainability for data center batteries

The uninterrupted power supply system provides two functions: one is to continuously regulate the power supply of IT loads, and the other is to provide short-term electricity to fill this gap when the emergency generator is online after the power supply of public facilities is interrupted.

In the context of data centers operating as bidirectional microgrids, there’re two key issues. Which battery technologies are most suitable as battery energy storage systems, and what are the proofs of sustainability ?

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, it is becoming increasingly popular due to its durability and smaller footprint. Compared to traditional lead-acid batteries, lithium-ion batteries are recycled ten times more frequently. Traditional lead-acid batteries, although cheaper, require more frequent replacement and are larger in size and weight.

However, in terms of the sustainability of the data center industry, this is not a direct battle between lithium ions and lead acid. Throughout the entire lifecycle of lithium, there are challenges to using lithium, from the need for large amounts of water extraction to the limitations of recycling. In contrast, lead-acid batteries benefit from the long-term established recycling supply chain, which can recycle over 98% of components.

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 batteries 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 upfront system costs, operating costs, cycle life, response time, floor space, and geographical dependence, liquid metal batteries seem to be potential game changers 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 choices.

Important factors include energy density, which refers to the amount of energy that can be stored in a specific area, volume, or mass. This, along 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 and may be applicable to the power demand of the data center. This includes power flywheel, compressed gas storage, as well as potential pumped storage, tidal flow, and gravity storage.

Sustainable battery selection criteria for battery energy storage systems

When selecting a suitable battery energy storage system, many interactive factors should be considered. This includes application types, sustainability performance indicators, investment and return on investment opportunities, technical performance, and location factors. It is crucial to consider the environmental impact of battery technology from the perspective of the entire lifecycle.