How Much Water Do Data Centres Use?
As the climate emergency deepens over time, it will become increasingly important for industries and sectors of all kinds to review their water usage and consumption to safeguard resources for future generations.
Given the predicted growth of the technology sector, however, it is perhaps particularly important for this industry to consider its water footprint and see what changes could be made to reduce it.
Some 29.3 billion devices are expected to be online by the year 2030 and these will need to be supported and backed up by data centres all over the world, providing power for millions of servers, as well as cooling and internet access.
The energy consumption of data centres is just one factor contributing to the environmental footprint of the tech industry and a growing area of interest is water consumption and what’s being done to address the issues of water stress and scarcity.
Research from the Centre for Environmental Policy at Imperial College London, published last year in the Nature journal, found that the US’s total water consumption in 2015 was 1,218 billion litres a day. Of this, irrigation accounted for 446 billion litres, thermoelectric power for 503 billion litres and potable water for 147 billion litres a day.
Throughout the whole of 2014, data centres in the country used a total of 626 billion litres and, while this may seem like a drop in the proverbial ocean so to speak, these facilities also have to compete with other users for local resources, which puts even more pressure on supply.
They consume water in two ways: directly through cooling processes for the servers and indirectly through electricity generation. Part of the problem is that, although investments have been made in the use of recycled and non-potable water, there are still some data centres that take more than half of the water they use from potable sources.
In places that are already facing serious problems because of water stress, this has become somewhat controversial and, as such, it is important to gain a deeper understanding of how data centres use water.
Data centre cooling
In data centres, technology equipment is housed within a room or hall, with heat ejected via an exhaust and the air extracted, cooled and recirculated.
There are various ways in which data centre cooling can be achieved but they all contribute to water loss through evaporation. Even a small 1 MW data centre using a traditional cooling process can potentially use approximately 25.5 million litres of water each year, according to the study.
Keeping the water cool is where the majority of the energy is consumed, but there are ways to reduce expenses, such as by raising the temperature of the chiller water. This means that there is less difference in temperatures between the water and the air, so costs can be cut.
Building data centres in cooler regions could also be beneficial, using cold air taken from the external environment instead of using cooling technology. Data centre facilities in hotter climates may well struggle to operate effectively without the use of chillers, however.
Information technology equipment
As the research goes on to explain, one way to measure how efficient cloud provider operations are is to look at the power usage effectiveness (PUE) ratios. The PUE measures how much energy input is used by tech equipment, rather than measuring data centre infrastructure like cooling.
PUE figures indicate how efficient facilities are at operating their equipment, including storage devices, networking and services.
With a PUE of 1.0 (the ideal), 100 per cent of the energy would go to power services, instead of being diverted to the likes of cooling and lighting. Because water is consumed through power generation, using this power more efficiently would mean that water usage would become more efficient as a result.
The shift towards renewables
Big-name companies like Microsoft and Google are now paving the way for the data centre sector in the move towards renewables and a more sustainable way of working.
At the end of November, Urs Holzle – Google’s senior vice-president of technical infrastructure – reaffirmed the company’s climate-conscious approach to cooling data centres, with the overall aim to operate on 24/7 carbon-free energy by 2039 and promote responsible use of water.
In a blog post, Mr Holzle explained that the brand’s climate-conscious cooling strategy involves finding the best solution for each individual site, taking into account local hydrology, energy, geography and emissions factors.
He went on to say that Google is also committed to using freshwater alternatives wherever and whenever possible, whether that’s wastewater, industrial water or seawater. Reclaimed or non-potable water is used at over 25 per cent of the company’s data centre campuses, thus far.
As for Microsoft, Noelle Walsh – corporate vice-president of cloud ops and innovation – blogged last year about what the company is now doing to find creative and innovative solutions to data centre operations to help achieve its sustainability targets.
Investment in research and development is now ongoing to help address challenges to significantly reduce and eliminate water usage for cooling, as well as reusing server parts to reduce e-waste and sustaining local ecosystems where data centres are located.
A commitment has now been made to reduce water usage in data centre operations by 95 per cent come 2024, which will mean that all aspects of the operations must be reviewed to reduce and eliminate water use.
For example, a new approach to data centre temperature management has now been rolled out to help save around 5.7 billion litres each year. And research is also underway in liquid immersion cooling to help deliver a future with waterless cooling options.
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