You may have seen the recent news that Thames Water has launched a probe into the impact of data centres on water supplies in and around London, as it imposed a hosepipe ban on its 15 million customers in a drought-hit area.
Ensuring that the data centre industry is sustainable has long been top of the agenda for data centre providers, as they work hard to use power and water responsibly. Indeed, companies in the sector are committed to innovative sustainability and renewable strategies that include ‘green’ renewable sources of power, rainwater harvesting, zero water cooling systems, recycling, waste management and more.
Why are data centres so important?
Data centres play a fundamental role in our society and digital economy – ultimately, they are the physical manifestation of the digitisation of our economy and are essential for day-to-day business. Everything that happens online is housed in a data centre, and without these physical facilities businesses and societies simply couldn’t operate. It’s no exaggeration to say that every segment of human activity – from energy, lighting, telecommunications and the internet, to transport, financial systems public health and entertainment – rely on this infrastructure.
It’s therefore no surprise that demand for instant 24/7 online computing and services has increased exponentially in the 20 years, and even more rapidly in the last five years. And data centres are the most efficient way of powering all of the technologies we rely on today. They are large, efficient, well-run facilities that are powered by renewable energy and more environmentally friendly than small, inefficient server rooms, found in business premises throughout the country.
Hence the classification of data centres as ‘Critical National Infrastructure’ in the UK, meaning that they’re essential for the functioning of society, with the government designating data centre engineers as key workers during the pandemic.
techUK reports that the data centre sector is one of the world’s largest markets and a real UK success story; leading in terms of technology and expertise and delivering year-on-year growth. Each new data centre contributes between £397m and £436m Gross Value Added (GVA) per year to the UK economy and represents a significant inward investment.
So, how and why do data centres use power and water? And how are they ensuring that they’re meeting their environmental obligations?
How do data centres use water?
In order to keep data centres working efficiently, effective cooling systems are vital to maintain optimum conditions in terms of temperature and humidity. This helps to ensure that IT hardware within data centres operates reliably and last longer, reducing the need for more resources to replenish IT hardware. All IT equipment generates heat from the electricity it consumes, and this heat needs to be controlled for the equipment to function and not overheat. Today, more and more providers are turning to chilled water systems as an economical and efficient way to maintain cooling. The good news is that chilled water cooling is both effective and efficient.
Importantly, the water used for cooling systems is often sourced sustainably, from bore holes or using impurified water: this is NOT the same 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. The data centre industry has long recognised the importance of water usage, with The Green Grid developing the Water Usage Effectiveness (WUE) metric to enable data centres to measure how much water a facility uses for cooling.
Secondly, 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 the average life span of a data centre being upwards of 15 years, this is an incredibly efficient use of water.
Thirdly, adiabatic cooling, which does require fresh water, is more energy efficient so provides other benefits. Adiabatic cooling makes up a relatively small percentage of the overall cooling infrastructure in the UK, and the sector is increasingly looking to do this from alternative water sources, without impacting mains supplies.
How much energy do data centres really use?
You have probably read that data centres are large electricity consumers and whilst this is true, it is another area where significant environmental strides have been made. For example, 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. At VIRTUS Data Centres, we use 100 per cent certified renewable energy, from sources including hydro, wind and solar. And encouragingly, renewable energy is now not only more affordable than fossil fuels, but also now more reliable too. VIRTUS have been a renewable energy user since 2013, with long term contracts in place to maintain this commitment. Many data centre operators are now also engaged in Power Purchase Agreements (PPA’s) with renewable generation operators, helping to increase the availability of renewables and supporting the UK governments net zero commitment.
Innovations like “dark data centres” have been important too – where power (including lighting) is only used as required. Most data centres will have occupancy sensors in the data halls and will turn lights off and on automatically only when people are present. Current research and development by data centre providers includes investigation into alternative fuel sources which could be used. For example, the use of Hydrotreated Vegetable Oil instead of diesel in generators has the potential to reduce carbon emissions by up to 90% – as well as eliminating sulphur dioxide emissions and reducing harmful nitrogen oxides. 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. That said, it is important to remember that generators are only used as a backup in the event of mains power being unavailable; we are fortunate in the UK to have a very stable mains grid. Allowing for limited start tests each month to ensure functionality, without a mains failure, generators will be run for around 2 hours per year. Data centre investment also leads to grid improvements, with data centres 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.
All of this progress is evident when we look at the statistics. 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. Data centres are early adopters of technological improvements, both in the plant used to operate the sites and advancements in IT such as High Performance Compute (HPC or supercomputing). This is where intensive workloads are run on smaller numbers of aggregated powerful processors to execute complex workloads in the most efficient manner, rather than on many smaller servers. This powerful statistic alone shows the significant environmental progress that has been made.
A collaborative effort
One good way of being publicly accountable and demonstrating sustainability efforts is to obtain certifications, providing a third-party verification of sustainability credentials. Building Research Establishment’s Environmental Assessment Method (or BREEAM) and Leadership in Energy and Environmental Design (LEED) are both sustainability rating schemes for the built environment, whilst also looking at the lifecycle of a building, from the concept and design to construction, operation and maintenance.
Other sustainability standards are ISO 50001 for Energy Management and ISO 14001 for Environmental Management. These provide a clear framework, allowing providers to thoroughly interrogate their effectiveness against green ambitions on an ongoing basis. SS 564 is another example, allowing providers to assess the energy efficiency of their data centre and provides a recognised framework as well as a logical and consistent methodology to achieve continuous improvement for their facilities. Certifications like these prove that some data centre buildings are some of the most efficient buildings in the UK.
Power Usage Effectiveness (PUE) is another way of demonstrating efficiency (and/or sustainability). It is a metric used to determine the energy efficiency of a data centre. PUE is determined by dividing the total amount of power entering a data centre by the power used to run the IT equipment within it. PUE and WUE levels continue to fall from an average of 1.6 ten years ago to between 1.2 and 1.3 today, with new facilities leading the way. The industry strives to deliver a PUE of 1.0, which demonstrates all the electricity consumed at a facility is for the IT equipment. At VIRTUS, we achieve varying PUE’s across our estate, all of which, according the Uptime Institute’s annual survey, are well below the 2020 average of 1.58x.
Of course, it’s important to remember that electricity and water usage isn’t inherently bad. For example, electric cars require power to run but are significantly less damaging to the environment than internal combustion engines.
Some data centre providers are driving change and leading by example, showing other sectors that by harnessing the brightest minds and cutting-edge technology, it is possible to “green” even the most power intensive industry. By sourcing the most sustainable materials and technologies for designing and maintaining these energy-intensive hubs, providers can run their data centres in a smart and clean way, ensuring that their impact on the environment is minimised as data consumption continues to thrive, but maintain responsibility, reliability and resilience.
At VIRTUS, we are committed to continue our work as an organization and with the wider industry to deliver on ambitious green commitments. We have a laser focus on sustainability and for a long time, we have recognized the need to produce more efficient data centres with lower and lower PUE and WUE designs to ensure we deliver the right service to our customers, at the right cost with the levels of reliability and efficiency they expect to deliver on their own sustainability programs. We continue to invest, innovate, and to broaden our view of the data centre with regards to sustainability, from the carbon impact of the physical construction of the buildings, right through to how we use natural resources such as rainwater harvesting, aquifers to access natural water resources, and even living walls on the exterior of our datacentres, supporting our commitment to be net zero by 2030.