Michael Sagar, Director of Marketing, Energy Systems at EnerSys, explains how lead-acid batteries can support the environmental goals of data centres.

The environmental impact of data centres is a growing concern, with the International Energy Agency (IEA) reporting that this sector accounts for 1-1.5% of global electricity use. Given this, data centre operators must prioritise environmental factors when choosing UPS battery units. 

During mains power outages, data centres require a reliable source of standby power for their critical infrastructure. One of the commonly deployed battery chemistries for this purpose is lead-acid. These batteries are often favoured due to their cost-effectiveness and high performance, contributing significantly to the global lead-acid battery market, which, according to Fortune Business Insights, is projected to grow from $45.84 billion in 2023 to $65.18 billion by 2030. Furthermore, lead batteries are recyclable, with a recycling rate of more than 99% in certain countries. 

Technological advancements have continually improved lead-acid batteries, making them a reliable choice for UPS systems. Indeed, manufacturers have introduced valve-regulated lead-acid batteries that require minimal maintenance and offer enhanced safety features. While some battery vendors compare alternative battery chemistries to conventional lead-acid technology, it’s important to note that advanced lead-acid batteries can offer superior performance in terms of electrical parameters, operational longevity, battery recycling, and renewable energy integration. 

Electrical parameters

Efficient electricity consumption is crucial for environmentally-conscious data centre UPS installations. Batteries that can charge quickly and efficiently reduce the power drawn from the mains supply grid. The architecture of some lead-acid data centre batteries ensures that the associated electrical demand is maintained to a minimum.

Additionally, accelerated charge rates are important from an operational perspective. Building up the State of Charge (SoC) rapidly prepares the data centre for the potential of subsequent outages in quick succession. Selecting batteries that support this is particularly important to site resilience. 

Operational longevity

The operating lifespan and performance of a battery will be limited by grid integrity, as explained later in this article. In an open grain grid structure, corrosion takes place. Acid exposure at the grid boundaries leads to a reduction in current carrying capacity, grid growth (through corrosion), and loss of contact between the grid and active material leading to the reduction of the active material area. 

Increased battery replacement frequency and associated labour costs emphasise the importance of selecting durable energy storage options. This achieves a more favourable total cost of ownership (TCO) while also reducing waste and lowering recycling needs.

Battery recycling

Disposing of batteries at the end of their usable life is an environmental concern. The Batteries Regulation is the first piece of European law that addresses and unifies sourcing, production, use, and recycling under a single legislative framework. Starting in 2025, targets will be introduced gradually for recycled content, material recovery, and recycling efficiency. Investigating the recyclability of battery types is, therefore, essential. 

Lead-acid batteries are highly recyclable. According to the Battery Council International (BCI), the trade association for the North American battery industry, the three main components of a lead-acid battery (lead, plastic and acid) are 100% recyclable.

Impacts of renewable energy

Operators should aim to improve their facilities’ environmental sustainability. A primary way to do this is by reducing the power that the IT consumes and lowering the carbon content of the utility supply. One way to effectively do this is by storing renewable energy in on-site battery energy storage systems, taking generated power from on-site solar panels and nearby wind turbines. This will supplement the power requirements of the data centre facility using low carbon solutions, improving site sustainability.

Enhanced lead-acid battery architectures

One appealing architecture to data centre operators is Thin Plate Pure Lead Battery (TPPL) technology. TPPL batteries offer elevated performance and extended working lifespans, with a typical design life of over 12 years when operated at a temperature of 20°C.

One of the key advantages of TPPL batteries is their significantly higher charge acceptance compared to conventional lead-acid batteries, allowing quick replenishment of the SoC. TPPL batteries are also highly efficient when operating in float mode, requiring up to 33% less electricity than other lead-acid batteries to maintain their charge. Their thinner plates also enable greater energy densities, which is a benefit at space-constrained sites.

Moreover, TPPL batteries are less prone to grid corrosion due to their pure lead grids, resulting in better structural integrity and higher efficiency. This durability makes TPPL batteries suitable for an on-site renewable energy storage system (ESS). As electricity supply networks become more dependent on renewable sources that are inherently more prone to fluctuations in power generation, batteries at data centre sites could be used to help maintain grid stability.

Prolonging the working lifespan of batteries, as TPPL batteries can do, may lead to considerable total cost of ownership benefits for data centre operators. TPPL batteries can operate at higher ambient temperatures, which lowers TCO further by minimising cooling costs. Additionally, TPPL batteries need less maintenance compared to conventional battery types and have lower ventilation requirements, which reduces operational expenses and keeps TCO down. 

As data centre workloads continue to grow, operators must enhance operational capacities while minimising their facilities’ environmental impact. TPPL batteries offer a compelling backup power solution with cost-effective upfront costs, minimal ancillary expenses, fast charging performance, prolonged lifespan, and high recyclability. By choosing TPPL batteries, data centre operators can align their operations with industry-leading environmental standards and contribute to a more sustainable future.