Tackling data centre power use by degrees

Reducing global data centre electricity use could be as simple as turning up the thermostat, say researchers from Hong Kong Polytechnic University. 

The researchers argue the problem of increasing energy consumption by data centres can be partly solved by raising the allowable temperature limit to 41^oC and taking advantage of external air for cooling, publishing in Cell Reports.

The authors calculate the simple measure could save 56% of the energy needed to cool data centres, compared to the typical indoor temperature of 22^oC.

Data centres are notoriously power-hungry infrastructure. 

Global data centre electricity use is estimated at 220 – 320 TWh (2021), equivalent to about 1% of global power use, the paper says.

For comparison, Australia’s annual electricity generation is 272 TWh.

Data centre power consumption is expected to grow to 848 TWh in 2030, due to ever increasing reliance on digital platforms along with growth in energy hungry AI.

Air conditioning or cooling in data centres makes up a significant share (about 30 – 40%) of total electricity use.

While some legacy data centres operated at 13^oC, modern servers are more robust and capable of operating at much higher temperatures, the researchers argue.

A non-mandatory standard (set by the American Society of Heating, Refrigeration and Air-conditioning Engineers) recommends temperature range of 18 – 27 degrees for data centres. In 2011 the standard was expanded, to reflect an upper limit of 40 – 45 degrees for certain classes of IT equipment.

Despite these developments, many data centre operators haven’t adjusted their thermostats, maintaining a typical indoor temperature of 22^oC.

The new research calculates the global energy savings that could be achieved by raising the temperature bar, across 57 cities in 19 climate zones. 

They say the optimal temperature depends on the city and type of server. 

There can be trade-offs between cooling energy use, and server power demand (due to increased fan operation) and reliability, the paper says. 

However, in most cases the energy saved through ‘free cooling’ using outside air instead of refrigeration, is larger than the increases in server power demand.