A progressive industry: tackling data centre sustainability myths

By David Watkins, solutions director for VIRTUS Data Centres.

Judging by the main stream media headlines, you could be forgiven for thinking that it’s been a bad few months for the data centre industry. The news that Thames Water is looking into the impact of data centres on water supplies was closely followed by a story on house building being halted due to purported data centre-related electricity capacity issues - and a very public spotlight was shone on the data centre industry and its sustainability.

Those working in the industry will know that both issues were sensationalised by the media, with limited investigation (or general education) as to whether data centres were actually the culprit for their accusations. The truth is that the data centre industry has long been committed to ensuring sustainability and efficiency, with providers working hard to use resources, including power and water, responsibly. As well as recognising this progress, it’s important for the general public to understand that data centres are fundamental to the functioning of the economy and modern society – without them, businesses simply couldn’t operate – but this is not widely understood beyond our industry.

So, what are the myths that need dispelling? And how are experts in the industry tackling sustainability issues and driving progress towards a greener future?

Myth 1: Cooling data centres reduces water supply for household use

One myth that needs to be dispelled is that data centres use enormous amounts of water to cool equipment and keep facilities working efficiently.

It’s true that more providers are turning to chilled water systems as an economical, effective and efficient way to maintain cooling. But importantly, the water used for cooling systems is often sourced sustainably, from bore holes or using impurified water: NOT the supply as we rely upon for household use. Indeed, Thames Water is already working closely with data centre providers to look at the possibility of using ‘raw water’ to cool their facilities entirely.

What’s more, the majority of large data centres use ‘closed loop’ chilled water systems, meaning that water is charged into the system during construction and then continually circulated within a facility, rather than needing new water consistently pumped into the building. A large-scale data centre will be filled with around 360,000 litres of water initially, or the equivalent of a 25 metre local swimming pool. Given this water is used as a ‘transport medium’ for heat, rather than being consumed, and that the average life span of a data centre is upwards of 15 years, despite what the headlines say, this is an incredibly efficient use of water.

Another cooling solution is indirect evaporative cooling which does require water periodically for adiabatic functionality, but it is more energy efficient so provides other benefits. This type of cooling uses fresh air from outside the building, which is filtered and then delivered into the facility for cooling purposes. This only requires the use of fans, so the overall energy consumption is lower. As outside temperatures rise, firstly compressors are brought on-line to provide additional cooling and only at high temperatures (24C or higher) is water consumed. Given that data centres operate 24x7, and temperatures above 24C typically only occur for a few hours a day across a small number of months per year in the UK, water usage is minimised.

Today, adiabatic cooling makes up a relatively small percentage of the overall cooling infrastructure in the UK, but the sector is increasingly looking deliver this method more widely, using alternative water sources, without impacting mains supplies.

Immersion cooling systems is another technology that is gaining traction. This involves bespoke IT hardware, that is immersed in dielectric liquids. These liquids are much better thermal conductors than both air and water, and do not require as much supporting infrastructure to ensure the IT equipment stays at the right operating temperature. This is not suitable for standard IT equipment yet but is an option for higher density computing requirements.

Myth 2: Data centres cause electricity capacity issues

It’s also true that the data centre industry requires significant power. But what the headlines fail to mention is that energy consumption is another area where significant environmental strides have already been made. The ability of data centre providers to make use of renewable energy sources has been game-changing in the industry’s pursuit of a sustainable future.

Power Purchase Agreements (PPAs) with renewable generation operators help to increase the availability of renewables and support the UK government’s net zero commitment. Investment in PPA’s delivers increased volumes of renewable energy to the grid, creates ‘green’ jobs and delivers cost certainty for operators and competitive pricing for customers that is not subject to energy market volatility.

Diesel powered generators continue to be the main source of standby energy for data centres, but research into alternative fuel sources is well underway. The use of Hydrogenated Vegetable Oil instead of diesel in generators has the potential to reduce carbon emissions by up to 90 per cent as well as eliminate sulphur dioxide emissions and reduce harmful nitrogen oxides, and there are number of these deployments already operational.

Other approaches are also being implemented where diesel is in use, such as remapping engines to run more efficiently and the addition of air scrubbers on exhaust systems which can reduce hydrocarbons, cardon dioxide and particulate matter by up to 90 per cent.

Hydrogen fuel cells are another emerging technology for providing standby power, and while not yet scalable to the levels required by a large data centre, can be used tactically within new builds - for example to support the office areas.

Of course, it’s important to remember that generators are only used as a backup in the event of mains power being unavailable and we are fortunate in the UK to generally have a very stable mains grid. Allowing for limited start tests each month to ensure functionality, without a mains failure, generators will only run for approximately two hours per year.

Data centre investment is also leading to significant improvements to the national mains grid, with data centre operators often directly funding the additional resources required, such as substations, to deliver the required power. The industry also has a long-term planning strategy to ensure capacity is available, so future power is secured ahead of time to limit clashes with local requirements. Combined with investments in PPA projects, this is increasing the availability of renewables, reducing the use of fossils fuels and the need to ‘import’ energy sources aiding the UK’s path to energy independence. As the demand for energy increases with the transition to electric vehicles, grid enhancement is essential.

A bright future Currently, many experts estimate that data storage and transmission to and from data centres use 1 per cent of global electricity. But this share has hardly changed since 2010, even though the number of internet users has doubled, and global internet traffic has increased 15-fold since.

There’s always more that can be done, and as well as celebrating progress we should be looking to the future, and to what we can do better. The key to future success? We believe that it’s only by working together that we will make the necessary steps to truly green the data centre industry for the long-term.

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