December 17th, 2020 by Tina Casey
When the topic turns to climate action, data centers are in the running for Public Enemy #1. They scarf up massive amounts of energy and their impact on global energy consumption is growing as the economy turns to cloud computing, cryptocurrency, IoT, and everything else connected to a modem. On the plus side, if energy storage enters the picture, their thirst for kilowatt-hours could become an asset to the grid. It could even translate into a revenue stream, which explains why Google is the latest to hop on the data center-as-battery trend.
Battery energy storage marries up with renewable energy at data centers (photo courtesy of Google).
Google Hearts Energy Storage
Tech firms like Google, Facebook, Microsoft, and Amazon have been leaning on renewable energy to tamp down on carbon emissions from data centers. With wind and solar, though, the data center still needs some kind of other source of power to fill in the gaps when output is low, or when an outage hits.
That extra source doesn’t necessarily have to include fossil fuels. It could be a large scale energy storage facility. The problem is that lithium-ion batteries are still the energy storage platform of choice, and they are still relatively expensive.
Well, that depends on relative to what. The expense of Li-ion energy storage can be counterbalanced by other bottom line factors, such as trying to stave off catastrophic global warming.
In addition, the cost of Li-ion technology has been falling. Earlier this week BNEF reported a 13% drop in the average cost of lithium-ion batteries year-over-year globally for 2019, and costs will continue to fall as new battery chemistries seep into the market.
Google dropped word to that effect earlier this week, with plans for a massive new battery at its data center in Belgium.
Google’s new venture addresses the power outage issue, which typically involves relying on diesel backup generators. Over the course of many years, diesel generators have amassed a proven track record of shunting wattage into a system within a matter of seconds after an outage, but it looks like diesel’s dominance over the emergency response field is beginning to wither away.
Diesel generators have come under attack from low-cost renewables, especially in smaller scale applications, or applications where trucking in diesel fuel is impractical or expensive. Now it looks like today’s generation of batteries has scaled up to deal the final blow.
“In Belgium, we’ll soon install the first ever battery-based system for replacing generators at a hyperscale data center. In the event of a power disruption, the system will help keep our users’ searches, e-mails, and videos on the move — without the pollution associated with burning diesel,” Google explains.
If all goes according to plan, the difference over current practice will be a significant one. Data centers already make extensive use of batteries, but mainly on a small scale as a supplement for diesel generators. Ditching the diesel generator entirely is a whole new kettle of fish.
As for what kind of battery it will be, that’s a good question. CleanTechnica is reaching out to Google for more details, and drop us a note in the comment thread if you have the inside scoop.
Who’s Gonna Pay For All This?
This is all well and good, but it won’t make all that much difference in the big picture of catastrophic climate change. After all, if diesel is only being used on an emergency basis, it accounts for a tiny fraction of the energy used by a data center. Add the fuel used for regular testing cycles and the number is still miniscule compared to other energy applications. In other words, why bother?
That’s where the value of energy storage-as-service comes into play. Unlike backup diesel generators, batteries can be used to provide grid services on a regular basis. The bottom line difference is significant. Diesel emergency generators are an investment that sits idle 99% of the time, or more, and then there’s that whole thing about paying for diesel fuel. An energy storage facility powered by wind turbines or solar arrays could provide grid services every day.
Google plans to leverage a 10,000-panel solar array at its Belgium facility for the new battery, and work with the local transmission system operator ELIA to fine-tune its contributions to the grid.
That’s just one data center. Diesel stakeholders may want to run for the Alka-Seltzer, because there’s plenty more where that came from.
“Worldwide, we estimate there are over 20 gigawatts of backup diesel generators in service across the data center industry, representing a massive opportunity to deploy cleaner solutions,” says Google. “Our project in Belgium is a first step that we hope will lay the groundwork for a big vision: a world in which backup systems at data centers go from climate change problems to critical components in carbon-free energy systems.”
Energy Storage-As-A-Service Mania Hits USA
Meanwhile, over here in the United States, CleanTechnica first caught wind of the energy storage trend back in 2012, when Apple announced an emergency generator setup based on fuel cells and biogas.
That fuel cell angle didn’t seem to go anywhere for a while, but now that the cost of renewable hydrogen has dropped, hydrogen fuel cells are catching more attention for backup power, among other uses.
Last summer, for example, Microsoft issued a lengthy blog post that underscored the ridiculous logic of keeping large, expensive pieces of diesel-powered equipment around on the off-chance they might be needed once in a blue moon.
Even without the green hydrogen angle, fuel cell technology has improved and costs have dropped in recent years. The problem, until recently, has been that almost all of the global supply of hydrogen has come from natural gas and other fossil sources.
For companies seeking to burnish their sustainability cred, renewable hydrogen ices the cake. The idea is to produce hydrogen fuel using wind or solar power to run an electrolyzer system that splits hydrogen from water, store it on site, and deploy it to generate electricity in a fuel cell (other green hydrogen sources are emerging, but water appears to be the frontrunner for now).
Microsoft’s blog post described what would happen if an Azure data center with on site hydrogen production, hydrogen storage, and fuel cells is hooked up to the grid.
“For example, the electrolyzer could be turned on during periods of excess wind or solar energy production to store the renewable energy as hydrogen. Then, during periods of high demand, Microsoft could start up the hydrogen fuel cells to generate electricity for the grid,” the company wrote.
Electricity transmission is not the only way to realize additional value from on-site hydrogen production. Hydrogen can be transported by truck, rail, or ship, or used as fuel by fuel cell vehicles. Microsoft is already anticipating that angle, envisioning data centers that double as fueling stations for hydrogen fuel cell trucks.
So far the idea has passed a 250-kilowatt proof-of-concept test. The next step will be a larger system that matches the output of a typical Azure diesel generator, at 3 megawatts. Producing and storing enough hydrogen for a 12-to-24-hour backup window is another milestone.
The Energy Storage Ripple Effect
As for up-front costs, a fuel cell system could cost about as much as a typical diesel generator within the next couple of years.
Microsoft anticipates that stepped-up demand for fuel cells by data centers could accelerate and perpetuate that trend, and that falls right into place with the US Department of Energy’s vision of a modernized, decentralized grid. With hydrogen energy storage and on-site wind or solar power, any number of farms, industries, and local communities could become self sufficient.
For the here and now, though, battery systems like the Tesla Megapack still appear to have an edge on large scale energy storage for data centers. There is plenty of room in that market, considering how rapidly the data center field is expanding (check out the global tech firm Switch for a good example).
Energy storage is just one clean tech angle involving data centers. Keep an eye on new developments in data center energy efficiency, as early adopters that help push the envelope for better, cheaper, more efficient systems.
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Photo (cropped): Data center with renewable energy in Belgium, courtesy of Google.
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About the Author
Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.