When the high-tech world of data centers touches the fabric of public life, it usually gets positive coverage.
Whether it’s heating a swimming pool in Devon or keeping students warm in Dublin, these data centers get good press for transmitting the heat they generate.
Heat radiates from the servers (computer stacks) inside. As energy bills soar, there is a clear interest in recovering this otherwise wasted energy. A study even estimated that excessive heat from data centers and other sites and devices could power most of Europe.
On the other hand, we are increasingly aware of the heavy burden that these machine rooms of the Internet place on the environment.
The ethereal-sounding Cloud – providing remote data storage – is something far more tumultuous in reality. It requires large amounts of electricity and water to maintain data centers go cool them.
In water-stressed Arizona, for example, there are warehouses full of computers that are licensed to use more than a billion gallons of water a year, enough to fill a Olympic-large swimming pool every day.
So is there a way to connect data centers’ oversized appetite for resources to their potential as producers?
How is data center heat recycled?
A washing machine-sized data center in Exmouth, Devon, is one of the latest to put its heat to good use, warming the waters of a public pool.
It’s a relatively simple process: the servers inside the white box are surrounded by oil to trap their heat. This hot oil is then pumped through a heat exchanger to heat the pool to 30°C, 60% of the time.
The start-up behind the initiative, Deep Green, has launched an innovative model: providing the “digital boiler” free of charge to the Exmouth leisure center in exchange for hosting its kit.
Location is a determining factor in the use of data centers and Deep Green is on a mission to decentralize the technology. If more companies switch to its “cleaner” IT services, the start-up says it could roll out boxes to every public swimming pool in England. And the more work there is on its servers, the hotter they get.
Recycling heat from data centers is not really new. In 2010, Finnish IT company Academica installed a 2 MW data center in the caves under Helsinki’s Uspenski Orthodox Cathedral.
Water heated while cooling servers provides heat to hundreds of homes across the city through its district heating system.
This type of central heating system sends hot water through a network of insulated pipes (through underground tunnels, in Helsinki), providing thermal energy rather than fuel which must then be converted into heat.
Some European countries are ahead of data center heat
Nordic countries Denmark and Sweden, as well as Latvia and Lithuania in Eastern Europe have a tradition of district heating. This gives them a head start when it comes to integrating excess data center heat.
But district heating can also work on a smaller scale. Ireland began building a network in the city of Tallaght in May 2021, and Amazonthe local data center now supplies it with hot water (via an energy plant and heat pumps). Students at Dublin University of Technology are feeling the benefits.
There have been many other attractive examples over the years.
A land-based lobster farm in Norway, an algae farm in Germany, and a hospital in Vienna are some of the various beneficiaries of data center heat. Researchers are also studying ways in which data centers and vertical trusses can collaborate rather than compete for space.
But there is a limit to good PR stories.
Why is data center heating not a great solution?
“The ideas here are very new and they’re welcome because it’s an industry that has a carbon footprint that needs to be reduced,” says Paul Deane, a researcher at University College Cork in Ireland.
“But unfortunately, these types of programs are relatively niche.”
There are several reasons for this. Large data centers tend to be located in industrial areas outside of residential areas, away from customers who might want to take the heat.
GoogleFacebook and other big business owners are less interested in niche apps, he says.
“They benefit tremendously from economies of scale and sizes of scale that suit their operations economically and environmentally as well,” says Deane. Large centers tend to be more efficient and have a relatively smaller footprint.
Also, the type of heat that most centers produce is low temperature. This lower quality heat must be compressed to higher quality to be useful, which tends to be prohibitively expensive.
In Germany, a proposal that data centers reuse their heat is being thwarted by the fact that utility companies would have to install expensive heat pumps to upgrade it.
And some places just have better options. Waste heat from heavy industries such as foundries or incineration plants is hotter, making them a bigger player in the district heating market.
In summary, these hurdles “do not tend to indicate that this is a game-changer or some kind of panacea for data centers,” Deane says.
“Look, these are great ideas in principle, but putting them into practice and implementing them is unfortunately very difficult.”
How to make data centers more environmentally friendly?
That doesn’t mean we should just enjoy our lettuce grown using data center heat or a butterfly stroke in a hot pool and raise our hands on the wider cost to the environment.
While these facilities are unlikely to be redeemable from a heating perspective, there are ways to reduce their environmental impact while reaping the economic benefits.
This has received particular attention for Ireland, which has a gigantic data center for a small country. It is in contradiction with its climate ambitions.
Researchers have warned that data centers could use up to 70% of electrical network capacity by 2030.
“Essentially – and data center owners are already very aware of this – if they want to reduce their environmental footprint, they have to increase the consumption of renewable electricity,” says Deane.
Many companies are windy and solar related projects, but it is essential to find ways to store large amounts of electricity – for use on gray and windless days.
“A lot of these data center companies have big and deep commitments to net zero goals, but they also have deep pockets,” he adds.
Use their “first mover advantage” to deploy renewable batteriesfor example, is the kind of leadership we need from big tech companies.
How can data centers cope with renewable energy declines?
Data centers can also reduce their electricity consumption when the wind drops.
“They could stop doing non-critical tasks, tag photos or download music or whatever and do it later in the day or week when they can use clean energy,” Deane suggests.
“But not all data center owners can do this because some of them are [processing] medical records or financial records that will be urgent.
There is clearly no single solution. And knowing what individual data centers are doing is difficult because their operations are understandably “shrouded in confidentiality and secrecy.”
However, some interesting principles emerge. Since Google has data centers around the world, the tech giant plans to shift tasks from one country to another when conditions are more favorable and make the most of clean electricity supplies.
Obviously, this type of digital leap forward in the world would not be possible for a small local data center.
But no matter how you slice it, big data needs to be cleaned up.
“It’s an industry we need, an industry we all benefit from,” says Deane. “But it’s an industry that needs to get cleaner and meet the goals it has set for itself.”