As the demand for data centres grows, so does their environmental impact, but some industry experts are advocating for a stricter “trinity” of reporting rules to help reduce the environmental impact of the expanding asset class.
To provide a more complete picture of the true environmental impact of data centres, a new Cushman & Wakefield report entitled Energy, Water, and Carbon: A New Trinity for Measuring Data Center Sustainability calls for measuring carbon emissions and water consumption in addition to power usage.
The standard metric for data centre sustainability, power use efficiency (PUE), is derived by dividing the total power consumed by IT equipment by the facility’s total power. Water use efficiency (WUE) keeps track of how much water is utilised for cooling and other operational requirements, whereas carbon usage effectiveness (CUE) calculates the carbon emissions from a data centre.
PUE has seen substantial advancements within the sector in recent years, with the industry average falling from about 2.5 in 2007 to 1.5 now.
Cool water from natural sources can used by water economists to cool data centres. The back of a server rack can receive cool water through rear door heat exchangers, which cools the hot air coming from the server at the source.
The limitations of measuring power alone have become increasingly clear as the industry evolves, said Managing Director, Data Centres & New Initiatives India at Cushman & Wakefield, Vivek Dahiya.
“Achieving a lower PUE is very dependent on the geography and climate of a data centre’s location,” Dahiya said.
“It is easy to achieve in the upper parts of the northern hemisphere but very difficult close to the equator where more power is required for cooling.”
According to NABERS, the average energy cost savings is $2,226,000 per annum when a data centre improves its NABERS Energy rating from 3 to 5 stars.
Dahiya said data centre operators were gradually adapting to accommodate the increasingly stringent environmental standards of both investors and occupiers.
“Data centre investors, operators and occupiers each have their own ESG ambitions,” Dahiya said.
“The challenge for the industry now is to continually improve the baseline standard to ensure that all requirements can be accommodated under one roof. A colocation data centre is only as sustainable as its least sustainable client.”
Gehan Palipana, Cushman & Wakefield’s Australian Sustainability Advisory Manager said generally hotter climates, like Australia, require an emphasis on cooling systems for data centres.
“The onset of climate change will see increased variability and hotter temperatures on average across the country which will make cooling data centres and maintaining stable operating conditions an even greater challenge,” he said.
Palipana said looking at energy efficiency is a key requirement in achieving a sustainable data centre, but it is only a component of the sustainability picture.
“Where that power comes from is also an important consideration, and without tracking the carbon emissions associated with your operations, there is no incentive for an organisation to move towards low or zero carbon emissions sources to further reduce their impact on the environment,” Palipana said.
“Data centres need to be measuring and tracking their water usage because the demand for data is increasing exponentially, which means more data centres, and more cooling requirements and ultimately more water use.
“Given that water is a critical natural resource, demonstrating responsible stewardship over its use will be an important measure of an organisation’s commitment to environmental sustainability.”