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Data centers: balancing climate change and digital growth

Valencia, Spain

Data centers: balancing climate change and digital growth

Valencia, Spain

Data centers are where the demands of digitalization and climate change collide. Organizations need new digital infrastructure to process and store the increasing amount of data they are generating – and they need it fast. But it is also necessary for that infrastructure to have as little impact as possible on the environment, and to run for decades despite a changing climate.

Technology company Cisco forecasts that annual data traffic will double to 4.8 zettabytes (4.8 trillion gigabytes) by 2022 – during which time more data will be crossing global networks than in the 30-plus years since the creation of the internet!

But as demand for data centers and the cloud computing services they support increases, so does the pressure – environmental, financial and regulatory – to develop them in a sustainable way.
In this article, we examine the four elements we believe are key to improving data center sustainability, all of which will be in much sharper focus now that coronavirus has accelerated the shift to remote working and living, namely:

efficient use of power
renewable energy sources
water and waste management
resilience to extreme weather events.

Time to adapt

Handling, transferring and storing the growing volumes of data produced by digitalization is very power intensive. In 2017, data centers in the US alone used more than 90 billion kilowatt-hours of electricity, equal to the output of 34 power plants of 500 megawatts (MW) each. Furthermore, keeping servers cool so that they operate as efficiently as possible requires huge volumes of water.

The technology giants who rely most heavily on data centers have set themselves ambitious renewable energy targets. For example, Facebook first committed to 100 percent renewable energy in 2011, followed by Apple and Google in 2012, and Microsoft and Amazon Web Services (AWS) in 2014.

For these hyperscalers who dominate the cloud services market, as well as data-center investors and co-location companies (colos) – who rent server space to third-party companies – making data centers more sustainable will cut their costs and enable them to meet their own carbon emissions targets, as well as government-imposed ones.

Efficiency – saving money, cutting carbon

Minimizing the power needed to run a data center is the best way to reduce its environmental impact and running costs.Energy losses through the data center’s cooling system can account for a significant percentage of the total power demand.

A data center’s power usage efficiency (PUE) metric is calculated by dividing the total power consumed by the power used solely for computing. The closer that ratio is to 1.0, the more efficient the system.

For example, a data center that needs 25MW to run its IT equipment and has a PUE of 1.67 (the industry average in 2019) would need nearly 42MW of total power to operate.By comparison, Google’s most efficient data centers are running at PUEs closer to 1.1 – at which level, a 25MW IT load would require only 27.5MW total power.


Assuming a price for power of $0.05/kWh, that difference in PUE would result in annual savings of more than $6million – or a total $94million over a 15-year lease. This also has implications for emissions. If the two data centers in the above example were using coal-fired power from the grid, the more efficient data center would save the equivalent of 90,000 tons of CO2 emissions a year.

Careful attention to temperature, unnecessary server usage and power storage dynamics are relatively low-cost ways to make data centers more energy efficient. Data centers use about 40 percent of their energy to keep servers cool.


Solutions to improve efficiency include passive cooling (a system that ensures hot and chilled air do not mix) as well as immersive liquid cooling, where servers are immersed in a rack filled with coolant that can have more than a thousand times the heat capacity of air. The coolant absorbs the heat from the servers and is then removed from the rack. However, recent research suggests that more than a quarter of servers in US data centers are ‘zombies’ – drawing power, but no longer being used for computing. New software solutions can locate them and make it easier to shut them down without affecting active operations. In addition, further power savings can be made with the latest uninterruptible power supply (UPS) systems that data centers can use to maximize reliability.

Renewable energy

Data center users and colos have led the way on renewable energy commitments, and tech companies are increasingly supporting the construction of new renewable energy within their own utility districts. The inevitable next step in this process is for tech companies and corporate data-center users to build their own renewable capacity, either right at their data center sites or within their utility service areas. AWS is investing directly in new wind farms in the US and Europe, including a new 91.2MW facility off the coast of Donegal, Ireland, to serve its data centers around Dublin. Solar is also a consideration for many companies if their locations are viable.

Whereas both wind and solar are reliant on the weather, tidal power is emerging as more reliable alternative. The predictability of tidal power means that the necessary energy storage systems can be sized effectively and economically.

Water management

The volume of water required to cool servers has made water management and recycling a top priority for data-center operators. For example, a 15MW data center can soak up more than 360,000 gallons of water a day. Water is not only a direct cost but used at such a scale can be a burden on local infrastructure and is an increasingly scarce global commodity.

As a result, data-center designers are being creative. In Finland, Google’s Hamina data center draws seawater from the Gulf of Finland for cooling. Rainwater can also be captured and stored for use in evaporative cooling systems.

Furthermore, wastewater can be a useful output – in the city of Umatilla, Oregon, there are plans to send wastewater from Amazon’s local data centers to irrigate nearby agricultural land. Resilience – floods, fire and drought are the reality of climate change


In order to ensure reliability, data-center designers and operators need to take climate change and its effects into account right from the start of the asset creation process. Extreme weather events such as flooding, droughts and lightning strikes caused by more frequent storms could be catastrophic. The choice of site must therefore consider the likelihood of increased flooding or droughts that could put essential water supplies at risk.

The digital revolution, climate change and coronavirus have changed the way we live and work, and digital infrastructure needs to adapt. Data centers should lead the way in the adoption of clean, sustainable technology, driving advances that directly benefit societies by limiting the use of finite resources and driving down the cost of data storage and processing.

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