While building data centers underground may be a good option for countries with scarce land resources and can bring greater security and resiliency, the process is expensive and time consuming due to technical and environmental challenges.
Last month, the Hong Kong revealed plans to build data centers in subterranean cavernsin a bid to create new space. "Rock cavern development can be done, and data centers use is a particularly good one. It's on the government's radar screen and it's taking active steps," Hilary Cordells, partner at a local real estate law firm Cordells, said in the report.
According to Cordells, there should not be legal issues as the person who owns the ground also owns everything underneath, but pointed out the environmental impact of construction could be high since water tables have to be lowered and toxic material must be removed.
Matthew Ball, principal analyst of IT research at Canalys, observed building data centers underground will be a good option where space is a premium and data centers have to be located next to the users.
Within Asia-Pacific, this includes mainland China, Hong Kong, Malaysia or Singapore, he noted.
Dan Olds, analyst at The Gabriel Consulting Group, also agreed, adding that buildable land in countries where land is scarce, is also very expensive so existing underground caverns can give the builders a headstart and help keep costs under control, he explained.
Won't reduce cost, technical challenges present
However, the cost and time of building underground will far exceed building above ground, Ball pointed out.
Even when a data center is built underground, it still needs large amounts of power, bandwidth, capabilities for cooling, good access for removing equipment and high level of fire detection, Ball explained.
Olds also added excavating caves can be "extremely expensive and time consuming", and it would be much easier to modify existing natural or manmade caverns rather than build entirely new caves.
Digging "deeply" into the earth for a large data center will be expensive and modifying an existing cave is not a straightforward process, he explained.
A cave's environment will also not be easy to control, Olds pointed out. For one, it is not "nicely sealed" like a building so water can seep in and even flood at times, he noted. Depending on the surrounding geology, it can be hard to identify the source of leakage and block it permanently, he noted.
"You never know exactly what you're digging into until you've already started, and most of the surprises in excavating caves are unpleasant and costly," Olds said.
The company will also have to determine if the ground is suitable for the construction of underground data centers, as there may be other facilities underground such as subways, sewers, water mains and electricity cables, Ball added.
The biggest attraction is the security and ability to withstand a wide range of natural disasters, but most general purpose data centers do not need this level of security and resiliency, Olds explained.
That said, even in land scarce areas, there are better and cheaper alternatives such as data centers on ships, using vacant office spaces further out of the central business district, Ball observed.