In deep water

There’s no avoiding the fact that data centres require significant resources, but what if they didn’t have to? Consultancy company Ramboll has a plan.

Data centres are essential to many aspects of modern life – consequently, electricity demand from data centres is growing rapidly. It is set to reach 130GW by 2028 according to BCG, comprising 3% of total global consumption. With this continued growth comes increased concern over the impact on the environment.

Ramboll has set out a plan to address the increasing negative environmental footprint of data centres. Its report Developing Sustainable Data Centres: A strategic roadmap to achieve net zero carbon and reduce environmental impact provides tangible solutions to solve the key challenges: embodied carbon, operational carbon, biodiversity, circularity, energy and water.

For example, the report advocates water reduction and reuse strategies, and recommends engaging landscape architects early in the process to influence site layouts and use biomimicry to minimise the ecological impact.

Ed Ansett, Ramboll’s Global Director of Technology and Innovation, says: “The construction of data centres powered by the rise of AI is booming across the globe, driving unprecedented demand for electricity and significantly contributing to global greenhouse gas emissions, increased water consumption, waste production, habitat destruction and resource depletion. These challenges can be managed and mitigated if data centres are built with climate, biodiversity and circularity in mind from the very start.”

The real-world impact on Earth’s water supplies

The Environmental and Energy Study Institute (EESI) notes that “a medium-sized data centre can consume up to roughly 110 million gallons of water per year for cooling purposes, equivalent to the annual water usage of approximately 1,000 households. Larger data centres can each ‘drink’ up to 5 million gallons per day, or about 1.8 billion annually – usage equivalent to a town of 10,000-50,000 people. One report estimated that the US’ 5,426 data centres consume 449 million gallons of water per day and 163.7 billion gallons annually (as of 2021).

“According to scientists at the University of California, Riverside, each 100-word AI prompt is estimated to use roughly one bottle of water (or 519 millilitres). This may not sound like much, but billions of AI users worldwide enter prompts into systems such as ChatGPT every minute and large language models require many energy-intensive calculations.

“A data centre’s water footprint is calculated as the sum of three categories: on-site water usage, water use by power plant facilities that supply power to data centres and water consumption during the manufacturing process of processor chips. Water can come from various sources, including blue sources (surface water and groundwater), piped sources such as municipal water and grey sources (purified reclaimed water). Using recycled or non-potable water to meet a data centre’s cooling needs is a well-established practice to conserve limited potable water resources, particularly in dry or drought-prone areas.”

Read more at b.link/EESI_data

University of Oxford research states: “Data centres accounted for around 1% or 2% of global electricity demand in 2020. All that processing power generates lots of heat, so data centres must keep cool to prevent damage. While some companies are using cool air on mountain sites and Microsoft has used the cold waters of Scotland to experiment with underwater data centres, up to 43% of data centre electricity in the US is used for cooling.

“This energy goes into cooling water, which is either sprayed into air flowing past the servers or evaporated to transfer heat away from the servers. Not only is energy required to cool the water (unless the system is specifically designed as a closed loop), but that water is lost as it evaporates. In a relatively small one-megawatt data centre (that uses enough electricity to power 1,000 houses), these traditional types of cooling would use 26 million litres of water per year.

“Water directly used for cooling is what most data centre operators focus on, but the largest source of water usage is actually electricity generation. This comes from how water is heated to generate steam, which turns a turbine and generates electricity.”

Read more at b.link/EngOx_data

A BBC article notes: “Dr Venkatesh Uddameri, a Texas-based expert in water resources management, says a typical data centre can use between 11 million and 19 million litres of water per day. His widely quoted calculations are based on arid, or semi-arid, climates and do not take into account recent efficiency improvements or developments in AI.”

Read the full article at b.link/BBCNews_water

These discrepancies are why the Royal Academy of Engineering has called on the government to ensure tech companies accurately report how much energy and water their data centres are using.

Read its report at b.link/Raeng_data

Tackling operational and embodied carbon

Data centres accounted for about 1.5% of global electricity consumption last year, a figure expected to double by 2030, according to the International Energy Agency. Due to the large quantities of energy consumed, operational carbon is the dominant component of total carbon emitted by data centres. The report believes that a net-zero operational carbon benchmark is within reach through optimised energy efficiency and renewable energy procurement, energy reuse and export, and demand response.

Data centres can further minimise their environmental footprint by implementing circularity practices. What is proposed is that all materials are reused, reusable or recyclable, with zero output to landfill or incineration. For example, embodied carbon – contained in the structure and materials of data centres – can be reduced by:

• using reduced carbon components such as lower carbon concrete, steel and mass timber
• reusing materials from decommissioned buildings or other sources
• employing construction practices that are powered by renewable energy and minimise waste generation
• improving the structural efficiency of the buildings to reduce the amount of material required
• using 3D printing technologies and prefabricated components to minimise waste
• using locally made materials to reduce transportation emissions
• prioritising durable materials with long lifespans such as natural stone, high-quality concrete or treated timber to extend service intervals and reduce replacement emissions
• using materials with proven resistance to degradation such as corrosion-resistant metals (eg galvanised steel), UV-stable plastics or moisture-tolerant finishes; and
• designing for maintainability and easy repair rather than full material replacement and avoiding short-lived materials in high-wear areas (eg soft flooring or low-durability paints).

“There are economic benefits for data centre owners if they focus on circular practices,” explains Ansett. “For instance, the sole physical byproduct of data centre energy consumption is heat, which has historically been unused and released to the atmosphere. Data centres are in an excellent position to export what would otherwise be wasted energy.”

Read the report at b.link/Ramboll_data

Image credit | iStock