Sustainability Considerations for Battery Option Selection in Data Centre Energy Storage Systems

By Ed Ansett, Chairman and Founder, i3 Solutions Group.

With new mandates such as SECR (Streamlined Energy and Carbon Reporting) and CSRD (Corporate Sustainability Reporting Directive) obliging data centre companies to report their sustainability efforts, a New GHG Abatement Group White Paper is published to help data centre operators work towards the ultimate goal of sustainable green energy storage.

Uninterruptible power supply (UPS) systems provide two functions: Continuous power conditioning to the IT load, and short-term power to bridge the gap while the emergency generators are coming online following the loss of the utility supply.

In the context of data centres operating as bidirectional microgrids, two key questions arise. Which battery technologies are most suitable as Battery Energy Storage Systems (BESS) and what are their sustainability credentials?

In a newly authored white paper, “Sustainability Considerations for Battery Option Selection in Data Centre Energy Storage Systems,” Clayton Lim, Associate Director at i3 Solutions Group and a contributing member of the GHG Abatement Group, explores the main factors that influence decision-making associated with current battery storage technologies together with important sustainability indices that ought to be considered. Trends in battery technologies are also discussed.

About Battery Energy Storage Systems

For grid interaction, the BESS consists of three main components:

● Battery Management System

● Energy Management System

● Power Conversion System

The data centre sector has traditionally used lead acid batteries with static UPS system, but that situation is gradually changing. According to a Frost and Sullivan 2021 report, lithium ion batteries will by 2025 account for 38.5% of data centre energy storage. Its growing popularity is reportedly due to its durability and smaller footprint; Li-ion achieves ten times the number of recycles compared with traditional lead acid batteries, which although are cheaper to acquire need more frequent replacement and are both bulkier and heavier.

However, in sustainability terms for the data centre sector, it is not a straight fight between Li-ion and lead acid. There are challenges with the use of lithium throughout its lifecycle, from its extraction which utilises high volumes of water to recycling constraints. Lead acid batteries, by comparison, benefit from a long-established recycling supply chain which can recover more than 98% of components.

There are alternative battery technologies that should be considered for use in the data centre. The new whitepaper Sustainability Considerations for Battery Option Selection in Data Centre Energy Storage Systems examines the following battery types:

● Lead-acid

● Sodium-sulphur (NaS)

● Sodium-nickel-chloride (NaNiCl)

● Nickel-cadmium (NiCd)

● Vanadium Redox Flow Battery (VRFB)

● Zinc Bromine Flow Battery (ZBFB)

● Lithium-ion (Li-ion)

Emerging battery types which logically could be considered viable alternatives to lithium ion include technologies such as the Vanadium Redox Flow Battery (VRFB), metal-air battery and sodium-sulphur battery.

The white paper states, e.g., “Liquid-metal batteries appear to be a potential gamechanger in the various UPS types given its superiority in upfront system cost, operating cost, cycle life, response time, footprint and geographical dependency.”

New pressure and regulatory concerns make battery choice increasingly important

Mandates such as SECR (Streamlined Energy and Carbon Reporting), CSRD (Corporate Sustainability Reporting Directive) and EED (Energy Efficiency Directive) will oblige data centre companies to report their sustainability efforts, this will also cover battery choices.

Significant factors include energy density which refers to the amount of energy that is available for storage in certain areas, volume, or mass. This in conjunction with power density and the right battery type determines the most suitable battery technology for optimal system selection.

The focus of the new white paper is on the sustainability characteristics of various chemical batteries for BESS requirements. However, it should be noted that other energy storage options are available which may be or become applicable for data centre power requirements. These include; kinetic flywheels, compressed gas storage, and potentially pumped hydro, tidal current and gravity storage.

Criteria for Sustainable Battery Choices for BESS

The new white paper concludes that many interacting factors should be considered when selecting the appropriate UPS BESS. These include the type of application, sustainability performance indicators, investment and revenue return opportunities, technical performance, and location factors. Critically, the environmental impacts of a battery technology must be taken into consideration from a whole life point of view.

By Ed Ansett, Chairman and Founder, i3 Solutions Group.
By Craig Brown, EMEA Channel Manager, Subzero Engineering.
By David Watkins, solutions director for VIRTUS Data Centres.
Marc Garner, VP, Secure Power Division, Schneider Electric UK & Ireland The data centre sector skills shortage has been documented by industry publications and research firms for almost a decade. In fact, a report published by Gartner in 2016 found 80% of firms expected to find their growth held back due to a lack of new data centre skills, with the McKinsey Global Institute predicting a global shortage of 1.5 million qualified data centre managers as early as 2015.
Big data, big energy consumption? Each photo we post on social media or email we send is saved into servers that are stored in physical data centres around the world. This process consumes a significant amount of energy, raising sustainability issues in the data centre industry. To help overcome this challenge, Marcin Bala, CTO of telecommunications networks specialist Salumanus Ltd, explains how to create a more sustainable data centre infrastructure.