Data Centers Challenge Our Region’s Sustainability

Alissa, H., Nick, T., Raniwala, A. et al. Using life cycle assessment to drive innovation for sustainable cool clouds. Nature 641, 331–338 (2025). https://doi.org/10.1038/s41586-025-08832-3

Using life cycle assessment to drive innovation for sustainable cool clouds | Nature

The article below is excerpted from the article cite above where Microsoft performed a life cycle assessed on the carbon footprint of data centers.

Since 2010, global internet traffic has increased more than 15-fold, with the sharpest jump occurring in the past few years. The increasing demand for cloud apps, machine learning, augmented reality, autonomous vehicles, artificial intelligence (AI) and other applications is driving the growth in data center traffic. This growth has sustainability challenges.

Generally, data centers consume 10–50 times more energy per square foot than typical commercial office buildings. In 2020 data centers accounted for approximately 1.5% (about 300 TWh) of global electricity demand. This percentage is expected to increase with the rapid growth in data centers. It should be noted that energy efficiency improvements in data center energy use has reduced energy intensity of global data centers has 20% annually since 2010, but this rate of improvement has been slowing and the rate of acceleration of data center construction and size has accelerated.

The information technology (IT) industry has benefited from efficiencies following Moore’s law (the number of transistors on a chip and the resulting processing power doubling every 2 years) and Dennard scaling (doubling the transistors per unit area for each new generation of semiconductors without altering their power dissipation). This dynamic has changed and resulted in a slowing of Moore’s law and Dennard scaling in the last few years. Now, improving chip performance requires more power and generates more heat.

Microsoft has committed to being carbon-negative and water-positive by 2030. As part of achieving this commitment, Microsoft has used life cycle assessment (LCA) to systematically analyze the potential environmental impacts of data centers (GHG emissions, energy and water consumption) and enable sustainability by design. When applied to the wider data center industry, LCAs show that traditional cooling technologies can make up 40% of the total energy demand of the data center.

Data center cooling systems, including required equipment, have been extensively reviewed. However, the Microsoft team reports that this is the first public LCA comparing the GHG emissions, energy demand and blue water consumption of air cooling, cold plate and immersion cooling completed by a hyperscale cloud provider. Air cooling uses by far the most electricity. Although hydrocarbon oils used in one-phase immersion cooling are recognized for their dielectric properties, low toxicity and low fluid loss, their high flammability is a safety concern, and their high viscosity creates pumping difficulties. Two-phase immersion can support very high tank power densities (+500 kW) but uses polyfluoroalkyl substances (PFAS) that have been under legislative scrutiny and may be banned entirely. PFAS and requires complex tanks and containment to control the forever chemicals. It would be insane to allow millions of square feet of tanks containing flammable or PFAS solutions all over northern Virginia to save 1-2% of CO2 emissions over direct contact cooling. The solution used for direct contact is flammable and needs to be properly handled and stored.

from Alissa, H., Nick, T., Raniwala, A. et al.air cooling above and plate cooling below

from Alissa, H., Nick, T., Raniwala, A. et al. both one phase and two phase immersion require tanks to submerge the processors

Nonetheless all cooling methods require air-handling units (AHUs) with evaporative cooling to provide cooling for the server rooms. Apart from AHUs for the server rooms, the cold-plate design and the immersion-cooled model uses fluid coolers to reject server heat by a heat transfer fluid. When outside temperatures is below 95 degrees Fahrenheit the fluid coolers can provide sufficient cooling without water (dry operation). However, above 95 degrees additional cooling capacity is required in which case adiabatic cooling (wet operation) is used. Adiabatic systems pre-cool warm outdoor air with water taking advantage of the temperature decrease when water changes phases from liquid to vapor. The bottom line is in Virginia, adiabatic cooling will remain part of the solution to keep data centers operating. Data centers will continue to consume water.  

Alimatou Seck, Senior Water Resources Scientist of the ICPRB found that data centers currently consume about 2% of the water used from the river basin rising to about 8% in the summer when adiabatic cooling is necessary. If the industry continues to grow at an unconstrained pace using standard cooling technologies, it has been widely reported that Dr. Seck  projected that number could surpass 33% by 2050, using 200 million gallons of Potomac water per day. This assumes that the cooling technologies remain the same mix as they are now. That assumption is very unlikely given the information in above study.

Alissa, H., Nick, T., Raniwala, A. et al. Schematic of liquid cooling