As discussed in the previous commentary, there is no shortage of battery options for the modern data center. From emergency backup to demand response, it has been established that the selection of chemistry that best solves the power challenge is the optimal path. But one other factor that must be considered (amongst many variables) is the holistic sustainability of that chemistry.
Many data center operators are rapidly moving to higher energy storage options to maintain power loads in the event of a grid-power outage or use for demand response, offset carbon emissions from diesel generators, or remove generators completely to use battery backup.
Furthermore, jurisdictions where data centers of all sizes operate are now requesting end-of-life sustainability plans for both power electronics and batteries. Furthermore, government agencies, such as the EU for their Battery Passport regulations, are starting to introduce legislation around the establishment of carbon footprint identification, percentage of recycled materials used, and specific reporting.
So, the question becomes: What does one do with batteries at the end of their useful life and how can it be done in an environmentally friendly manner? Let’s start with a definition of sustainability to set the conversation. Sustainability is defined by Oxford Languages as “avoidance of the depletion of natural resources in order to maintain ecological balance.” As electrochemistry continues to evolve, so does the ecological footprint of its makeup, and this must be considered just as much as battery performance.
While there are several options, both new and established, for batteries to choose from, we will focus the conversation on the three mainstream battery types being deployed into data centers: lithium-ion, lead-acid, and nickel-based chemistry.
We thought it best to ask the experts and turned to some industry companies to help us understand these three chemistries better with regard to their sustainable footprint.
To start with, the battery manufacturing industry standard for sustainability comes from lead-acid batteries. With lead-acid technology being over 150 years old, it may seem hard to imagine anything with this aging of batteries can come across as innovative, but in fact the chemistry itself is leading the way for being a sustainable footprint for other peers in the industry as well as breakthrough in performance innovation.
“Lead batteries of all shapes and sizes are what is recycled the most in industrial applications,” says Jeff Batalucco, program and business development manager of Vesco Oil Corporation.
“Lead acid shows as one of the most circular and sustainable batteries on the planet, being able to reuse the lead plates, plastic jar material, active electrolyte, and terminal constructions. It is virtually 99 percent recyclable and has infrastructure everywhere to collect, properly transport, store, responsibly process, smelt for ingot production, and build new lead acid batteries.”
While being a true circular-economic product, it does have some drawbacks in the processing of smelting, requiring some pyrometallurgical processes and recorded incidents of improper recycling leading to environmental pollution. These are being offset by increased regulatory oversight and the addition of renewable power generation and energy storage to these facilities. Nevertheless, lead-acid is the model that is established, setting the baseline for others to follow. Data centers today that use this technology should find a good balance of sustainability to meet environmental objectives while maintaining mission-critical power security.
Following closely behind in the battery circularity race is lithium-ion. While still a relatively new chemistry, only in the last few years has recycling for this chemistry become mainstream. There is a common myth that lithium-ion batteries cannot be recycled. This is a false statement; they can be recycled and are processed in volume today. However, in 2024, the lithium-ion recycling industry is in a minor slowdown volume period, mostly driven by EV demand slowing in the first part of 2024 and commodity pricing being volatile. This doesn’t mean any progress is being deterred, quite the opposite as several companies are constantly evolving new technologies, procedures, and logistics operations.
“Not all lithium-ion batteries are created equal in terms of sustainability,” says Mark Steadman, program manager of Call2Recycle. “Variations in rare-earth elements contribute significantly to the process of mineral extraction to create specialized material, known as Black Mass, to sell back to lithium-ion cell producers for extraction of these elements to create production-ready cathode and anode mix.”
“Lithium-ion chemistries like nickel-manganese-cobalt carry high concentrations of reusable materials that can be made into black mass for production-grade raw materials but others like iron phosphate have little to no elements available for processing and manufacturing reintroduction,” Steadman goes on to say.
Like lead acid, it does have some drawbacks in current processing, requiring some hydrometallurgical or pyrometallurgical processes, resulting in a potential increase in carbon emissions. Just like lead-acid, these drawbacks are being offset by increased regulatory oversight and the addition of renewable power generation with energy storage to these facilities.
Data centers needing to report end-of-life plans for their electronic assets should rest assured knowing that lithium-ion chemistry processes are already established and continue to adapt to changing regulatory requirements.
One piece of chemistry that is often overlooked in terms of sustainability but should not be disregarded, is nickel-based technologies. While being very mature in terms of chemistry like lead-acid, nickel-based batteries also play an important role in understanding their circularity of energy and power storage options.
Eric Fredrickson, vice president of operations at Call2Recycle, notes, “With regards to nickel-based batteries, it is very important to differentiate between the variations in chemistry types. For example, nickel-cadmium batteries present many challenges to the recoverability of nickel elements due to the toxic and hazardous cadmium. Whereas with dry-cell based technology like nickel-metal-hydride, it is much simpler and easier to disassemble and recover the nickel from those batteries.”
“One area to keep a close eye on is how to disassemble and process these batteries at the end of life. Processing these chemistries is becoming limited in the United States, especially for wet-cell based technology, as there is only one domestic processor left that can handle nickel-cadmium.” Fredrickson goes on to say. Data center operators choosing to deploy nickel-based batteries also have select options on how to recycle their batteries at end-of-life.
As battery demand is only growing as power demands increase, so will the sustainability footprint of each of these batteries. It is important to note that all battery chemistries are not created equally when it comes to their overall carbon footprint, economic circularity, and overall recyclability. Bottom line, data center operators must understand these trade-offs to ensure these batteries at the end of their useful life do not end up in landfills and move to the proper recycling channels. How they are used, collected, shipped, processed, and converted to reusable materials plays an important role in data centers achieving sustainability goals while maintaining power demand requirements.