Data Centres use cooling water, but the electricity used leaves a greater footprint. CEP used water footprinting techniques to measure this impact.
Download less; save water!
It is estimated that 60% more water will be needed over the next two decades to feed growing populations. However given today 15% of the world does not have access to clean water the enormity of the looming global water crisis becomes evident. Data centres which house servers and other equipment, transferring information around the world, directly use water for cooling, but the vast amount of electricity used leaves an even greater footprint. Using the Water Footprint methodology, researchers at the Centre for Environmental Policy (CEP) are trying to account for the amount of freshwater that has been evaporated, used or polluted, by data centres. This allows for comparisons between different uses like those in agriculture and industry. While a fair amount of a data centre’s water use is not consumptive, it can reduce water quality, further constraining scarce water resources.
The information and communications technologies sector is the fastest growing electricity consumer in Europe and is among the fastest in the USA. This means that the sector is soon likely to overtake aviation as a source of carbon emissions. While the effect this has on climate change is an extremely important part of understanding the impact ICT has on the environment, it is not the whole story.
Dr. Kaveh Madani, who directs the data center water impact research at Imperial College, says “Many people are surprised to find out that the data they use has a measurable impact on water availability. Given rising concerns over the availability of water around the globe, it is vitally important that we understand all the different impacts of this rapidly spreading technology. The water impacts of the Internet, data, and data centres have been overlooked. People do not know that they can save water by putting their phones on airplane mode or by spending less time on Facebook and YouTube.”
In 2011, the average UK household used about 17 gigabytes of data per month. At the high end of the range of likely values for the water footprint of data centres, this would mean that the average household generated a 3,400 litre water footprint per month from only its data use. This would be about 3% of the water footprint per person in the UK. While that does not sound like a lot, it is roughly equivalent to running an old water-intensive washing machine about 20 times per month.
“There is a lot of uncertainty and variability around the different processes using water in data centres, but their combined water footprint can be as high as 200 litres per gigabyte of outbound data. This means it can take the same amount of water to get a GB of data to you as it takes to deliver a kilogramme of tomatoes.” says Bora Ristic, Ph.D. student at CEP and lead author of the “The Water Footprint of Data Centers”, which was recently published in the journal Sustainability.
The Internet has been spreading at an astonishing pace. Between 2001 and 2013, the share of humanity with access to the Web rose from 8% to 38%. The amount of data transmitted online has been growing exponentially over the past decade; 100 gigabytes per second (GB/s) in 2002 to 28,000 GB/s in 2013. This growth in the information economy would not have been possible without simultaneous growth in the physical infrastructure supporting it. Between 1997 and 2007, the number of servers deployed to meet our data needs saw a seven-fold increase. The effect this is having on the environment is then becoming urgently important.
IT equipment not only needs cooling but also uses a lot of electricity. The generation of this electricity also usually involves evaporating and polluting water. This indirect water footprint typically constitutes the greatest part of the total water footprint of data centres.
Dr. Zen Makuch, Director of CEP and co-author of the paper, highlights the role of innovation in addressing the environmental effects of data centres. “As we see with many environmental problems, reporting and information disclosure in this area is still quite patchy, making it difficult to know exactly what the impacts are. Close collaboration between business, regulators, and other stakeholders will be crucial in delivering innovative ways of reducing our impact on the environment. This paper is a good example of how inter-disciplinary research being done by departments like ours can help to understand and reduce the environmental burden of our activities.”
One way of reducing the water footprint of data centres is to locate them in cool parts of the world where the outside air can be used for cooling. Many large companies like Facebook are already building new data centres parts of the world where data centre water use can be lower. Because of the water footprint of electricity it is just as important that data centres be powered by electricity that is not made in a water intensive way such as that from geothermal, solar, or wind energy.
Even as we welcome the benefits of the internet we must endeavour to find ways in which to reduce the environmental footprint it leaves behind. This sometimes leads to surprising conclusions like the idea that, like printing less, downloading less can reduce water and environmental footprints.
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Centre for Environmental Policy
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