The E-Waste Column no. 219

1 day ago

2 min read

Today, we are looking at alternatives to poly- and perfluorinated alkyl substance (PFAS) use in datacenter cooling systems.

🌱 How are most datacenters cooled?

PFAS-free cooling technologies for datacenters exist, and the majority of the datacentres globally still use these. Most datacenters “rely primarily on air-cooling”, and the “use of single-phase PFAS-free liquid-cooling is growing quickly”. In practice, a large amount of datacenter cooling is done through mechanical cooling, such as by air conditioning or other chillers. The liquid-cooling systems commonly used operate with “liquids derived from oil and gas”. Natural refrigerants such as ammonia, CO₂, isobutane, and propane can all be used in commercial scale liquid-cooling systems for datacenters.

🌱 Do datacenters need PFAS cooling systems?

While natural refrigerants and other PFAS-free commercial alternatives exist, the use of large tanks containing PFAS is currently being heavily marketed as a cooling technology for datacenters. There is “a new generation of F-gases that have low global warming potential” and a high “energy and water efficiency”. Given these characteristics, PFAS producers are marketing these F-gases as a “sustainable” alternative for datacenter cooling. Across the board, it can also be said that chemical companies are significantly increasing their production of PFAS for datacenter cooling systems.

🌱 What environmental risks does PFAS cooling pose?

The problem with PFAS-based cooling technologies for datacenters is that they use huge quantities of PFAS. These so-called “forever chemicals” can leak into the environment from datacenters or cause significant problems at their end-of-life, when the chemicals are disposed of. Beyond this, it is also worth pointing out that the factories that produce PFAS can pollute surrounding soil and rivers, as well as the air. It is worth saying that “[o]nce PFAS is in water and soil, there is no realistic way to clean it up”. That being said, the amount of PFAS used by datacenters – and the harm this creates – is not fundamentally determined by the amount of AI being used, but more by the choices made around which cooling systems to use. Responsible decision-making, democratic control, and effective regulation can therefore play a key role.

🌱 How can harms from datacenter cooling be mitigated?

There are several measures that can help to mitigate the environmental harms caused through datacenter cooling. Using renewable energy in place of fossil fuels to power and cool datacenters is important when it comes to cutting their greenhouse gas emissions. Reusing so-called “waste heat” from datacenters to heat homes also helps to cut these emissions. Using PFAS-free cooling technologies, such as “single-phase and closed-loop natural-refrigerant engineering”, is key when it comes to avoiding chemical pollution and soil, water, and air contamination. It would also be helpful if datacenters opted “to install cooling systems that can be updated as the technology develops” to reduce the risk of making PFAS cooling or other suboptimal cooling solutions “permanent by default”.