New uninterruptible power supplies (UPS) are often based on lithium-ion (Li+) battery technology, widespread in everything from cars to computers. This usually accompanies a claim of greater sustainability that could help relieve the pressure on operators for greener data centers.
Yet, the sustainability picture around Li+ batteries is unclear, with global challenges around mining and manufacturing still unresolved. However, Janne Paananen, Eaton Europe, Middle East and Africa (EMEA) critical power systems technology manager, says that operators need to take a holistic view of all issues affecting power management, “thinking smarter” about the role of UPS rather than buying the greenest or most efficient.
Instead, Paananen suggests operators must start making more intelligent use of existing assets, reducing overall consumption to simultaneously save costs and environmental resources.
“When you are not thinking in silos anymore, that means you don’t need to make separate purpose-built systems for everything,” Paananen says. “Think about the whole electrical equipment system at once: everything connected, how it can contribute.”
Ciarán Forde, data center and IT segment manager at Eaton EMEA agrees suppliers often develop sustainably oriented products with multiple commonplace elements. “Ask what that infrastructure can do to move the needle on sustainability?”
He says the core issue is that electricity is still primarily generated via oil and coal-fired plants. A data center reliant on fossil fuels for power can be maximally efficient while still not advancing the sustainability agenda of its operator or the users that depend on it.
Of course, the UPS reduces the chance of disruption when problems arise by delivering breathing space to ramp up on-site backup generation, securing the resilience of applications and workloads. However, more sustainability can be achieved, Forde suggests, by understanding UPS as a focal point.
UPS is part of the nerve center of the energy network, which means that sustainable UPS, regardless of technology, must incorporate the right smarts.
For instance, intelligent UPS that monitors requirements and predicts demand can help offset data center energy consumption by enabling stored energy to be delivered back to the grid for others to use.
The data center can become a prosumer: increasing the overall sustainability of its systems and operations, especially if it begins delivering power to the grid via renewable sources, perhaps by installing solar panels.
“If enabling the grid operator to adopt more renewable energy, your contribution to sustainability is then an order of magnitude higher than tweaks here and there on efficiency inside the four walls of the datacentre,” says Forde.
Paananen adds that old technologies, such as lead-acid batteries, are not necessarily less environmentally friendly – with new metallurgical and hydrometallurgical techniques being explored, recycling plants built, and component tracing strategies, such as the Global Battery Alliance Li+ battery passport, in development.
“You can recycle 99% of the lead from the batteries. With lithium batteries so far, they’ll last 10-15 years in operation, so you don’t expect any reasonable amount of recyclable materials from new lithium batteries until 2030,” Paananen says.
Marc Garner, UK and Ireland vice-president of secure power at Schneider Electric, notes that the environmental impacts of lithium at specific points in the lifecycle can be higher than some “competitive” alternatives. However, benefits at other stages of the lifecycle can often offset this.
“Studies found that over ten years, Li+ delivered a total cost of ownership 10-40% lower than equivalent systems using valve-regulated lead-acid (VRLA) technology.”
Schneider sees legacy operators selecting Li+ battery-powered UPS as “part of modernization and energy management strategies,” – especially since Li+ batteries are now only 1.2-2 times as expensive as VRLAs.
“They also offer two to three times the lifecycle of VRLA batteries, have two to three times faster charging recycles, a smaller footprint, and lighter weight. Some three-phase Li+ models offer intelligent energy storage options.”
Partnering with smart-tech supplier Wärtsilä on UPS has demonstrated average capex savings of 27% and emissions reduction of 20%. Over time, regulatory compliance is coupled with evolving technology and take-back or trade-in options for UPS and end-of-life battery replacement, Garner adds.
What the science says
Nuria Tapia Ruiz, a senior lecturer at Lancaster University, researches energy storage materials about battery technologies. She agrees the picture of sustainability is complex.
“Li+ is not so sustainable,” Ruiz confirms. “But lithium and a combination of nickel, cobalt, and manganese ratios can provide the highest energy density, so can store quite a lot of charge.”
Lithium reacts with air and water, and its mining is associated with multiple environmental issues. Nickel extracted from sulfates generates toxic sulfur dioxide.
Congolese cobalt mines not only use child labor but cause pollution-related health problems, including contamination of drinking water. Meanwhile, gaining full transparency on battery manufacturing and supply chains to close the loop and eliminate unnecessary waste remains difficult.
About 70% of the cobalt in batteries comes from the Democratic Republic of Congo. Ruiz says: “On the anode side, we have some carbon. Which, again, comes with sustainability problems because carbon is made from coke.”
Current battery technology seems a stepping stone in the right direction rather than a sustainability solution.
“If we’re looking at sustainability, we’ll move towards changing cathode materials towards, for example, phosphorus, oxygen, iron, and lithium – getting rid of the cobalt and nickel,” Ruiz says. “Other sustainable technologies we are looking at include sodium-ion (Na+).”
Na+ technology is a research interest of Ruiz’s and a decisive next step for battery technologies – especially considering that the second-largest battery maker CATL unveiled its first generation of Na+ batteries as a Li+ alternative in July, forecasting supply chain readiness by 2023.
“And in 20 years, calcium or magnesium batteries show quite a lot of promise,” Ruiz says. “They have more potential in the performance matrix.” Meanwhile, research continues to improve Li+ technologies and applications.
Best practice UPS sustainability for today
Tony Lock, a distinguished analyst at Freeform Dynamics, says data center operators should achieve sustainability goals by first focusing on their basics: assessing the business criticality of applications and services, which platforms they should run on, how efficient the servers and storage are, and so on.
“What are you running inside your data center for which you need continuous availability? Not all workloads are created equal. Even though nearly everybody who uses a workload will claim its mission-critical, many aren’t,” Lock says.
Some may need less battery backup, shutting loads down smoothly when not required, limiting the size of UPS, and alternative power systems as necessary for the event of an outage.
“Trust me, I have been in the data center when all of the power disappeared, actually about 15 minutes before we tested the battery of the backup diesel generator,” Lock says. “We did blame the electricians for that, but it was a fire alarm.”
As for alternatives, Lock advises: “Use some of the flywheel technologies, like large springs, that have come along – perfect if you don’t need to keep things running for hours. These can be taking a trickle charge.”
It all comes back to only keeping things running if you need to, Lock emphasizes. Datacentres also should have alternative electricity providers on hand via diverse routing; that way, other supplies can be accessed via different wires.
“Minimise the amount of less environmentally friendly systems, including UPS systems that store capacity,” Lock says. “And a more educated population is growing, and will be shareholders intent on making organizations as green as possible – that social factor has changed dramatically in the past five years.”
Chris Brown, chief technical officer of Uptime Institute, adds that a rotor UPS or a big flywheel has a mass on it and therefore inertia, which will be advantageous in some situations – for example, if producing the power rather than just consuming it – but not others.
“On the static UPS side, you can use a small flywheel to replace the batteries. The issue with that is now your typical battery runtime on a static UPS, somewhere between five minutes and hours, depending on how many batteries you want to put in a flywheel, will give you about 18 seconds,” says Brown. “So you do need a fast start-engine generator or something of that nature associated with it, but it does eliminate the need for batteries.”
Another option is double-conversion stack UPS, using a rectifier to convert AC to DC that will then be used to charge batteries and then convert the DC via inverter back to AC to drive the UPS. When some features are converted from AC to DC, you remove all power anomalies. Says Brown, you can also use an “eco” mode that bypasses the UPS until the power disappears.
What the data center needs for sustainability is the best possible energy efficiency and battery storage with the lowest overall environmental impact throughout the lifecycle – “burning the lowest number of dead dinosaurs” in the process, he says.
Brown says that Uptime has even heard that some insurance companies are pushing back on the use of Li+ because of the fire risk. But there’s no perfect answer to optimal power management via UPS.
“You can control the space that the batteries exist in for optimal conditions that will extend their life – selecting battery technology that’s right for what you’re going to use it for,” says Brown.
“The other thing is support. When you’re talking about battery technicians who can extend the battery’s life just by knowing what to do with it – that’s as much an art as a science. With a lot of experience, they’re worth their weight in gold, but not every data center has that kind of expertise available.”
