Data centres will need to implement new efficiency measures to prevent their electricity usage spiralling in the next decade, researchers in the US report.
Data centres have only been able to stabilize their electricity usage over the past decade – despite rapidly increasing demand – because of efficiency improvements, particularly the shift from small to large facilities, the team found. But such efficiency improvements will not be enough for future energy stability.
“A lot of the efficiency gains [in] data centres so far have come from correcting some pretty egregious energy wasting practices – things like allowing cold and hot air to mix together, or continuing to run servers that aren’t actually doing anything useful,” says Arman Shehabi at Lawrence Berkeley National Laboratory, US. “Once [these have been corrected], the potential for improvement slows down. We’re not there yet, but … it’s not too far away.”
Over the past two decades, data centres have been the backbone of the digital economy, responsible for processing more and more zettabytes of data. But their services come at a high energy cost; the centres are estimated to require between 10 and 100 times the electricity per unit of floor space as other types of infrastructure.
A 2007 report for the US Congress found that, in the previous year, US data centres consumed some 60 billion kilowatt-hours (kWh) – 1.6% of total US electricity sales – at a cost of about $4.5 billion.
Two years ago, however, the US Department of Energy reported a surprising slowdown in data-centre energy growth since 2010. The precise reason was unknown, which is why Shehabi and colleagues from Lawrence Berkeley, Northwestern University and Koomey Analytics attempted to find out.
The researchers developed a model to characterize IT equipment in US data centres from the bottom up, based on information in the literature and more than 30 experts on data centres. The model included parameters to adjust the distribution and characteristics of the equipment. And the researchers fed in data on equipment sales compiled by a market-research firm.
Their main finding was that, in terms of energy usage, the massive increase in data-centre workload of recent years has been offset by relatively straightforward efficiency measures made possible by an adoption of larger-scale infrastructure. Such measures included the use of cold air taken from outdoors for cooling, and maximizing the workload from individual processors.
Had efficiency practices stayed the same since 2010, the researchers found, US data centres would be on course to consume nearly 170 billion kWh of electricity by 2020, compared with the 72 billion kWh implied by current trends. On the other hand, the analysis showed that efficiency measures could have been made faster: had this been so, usage at 2020 would be more like 45 billion kWh.
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According to Shehabi, the 125 billion kWh difference in potential electricity usage for 2020 illustrates “just how different electricity demand could be from the near flat growth we’re experiencing now”. Decreasing or even maintaining stable demand after 2020 “depends on finding and implementing new efficiency measures to offset demand growth,” he adds.
Such measures could include breakthroughs in chip design for servers, and liquid cooling, according to Shehabi, who reported the study in Environmental Research Letters (ERL).
