A recent application submitted under the Toxic Substances Control Act (TSCA) has drawn criticism from environmental groups because it involves the proposed use of PFAS to cool equipment used in data centers.
The TSCA requires companies to apply to the U.S. Environmental Protection Agency before manufacturing or importing new chemical substances, which are those not already listed on the TSCA Inventory. The new chemical, named Opteon 2P50, which is a per- and polyfluoroalkyl substance (PFAS), is intended to be used to cool electric equipment. In the submission, it is argued that the new chemical would drastically reduce the amount of water used for cooling purposes in data centers by 90 percent and overall reduce their energy use by 40 percent. Proponents argue that by reducing the overall energy requirements, data centers can be built quicker and use a smaller footprint due to increased energy effectiveness.
Opteon 2P50 is intended to work as part of a two-phase immersion cooling, utilizing its unique heat transferring properties. First, electronic equipment will be placed inside a tank filled with Opteon 2P50 (because it is dielectric, i.e., non-conductive, and it is safe to merge equipment in without damage). The electronic components as they heat up will naturally boil the Opteon 2P50 and convert it into vapor. The vapor then works to absorb and remove the heat. The vapor is then condensed and converted back into its liquid form, and the cycle begins once more.
But environmental groups argue that this new chemical will degrade into short-chain PFAS which have a higher mobility in water, allowing it to move faster and thus creating difficulties in removing it, expanding the area of potential contamination. Environmental groups also note this is difficult to remove from drinking water as they can often bypass the typical treatment filters used to treat drinking water.
Although proponents tout the energy effectiveness of this chemical, environmental groups point out that large quantities are still required to cool equipment, citing that a single two-phase immersion tank can contain 1,270 liters of Opteon 2P50. Furthermore, they state that a data center would contain hundreds of these tanks requiring tens of thousands of liters of Opteon 2P50. As these tanks are replaced and the liquid is disposed of, a leak can lead to significant release of PFAS gasses into the surrounding environment. They further cite studies that show the short chain PFAS which will be produced from this new chemical are associated with developmental, liver, and thyroid issues.
The Opteon 2P50 submission underscores the broader tension facing data-center development. Cooling technologies that reduce energy demand and water use may offer meaningful benefits as data centers continue to expand. However, those benefits must be weighed against the potential environmental consequences of using PFAS-based chemicals. As regulators evaluate this and similar applications, the question will not be simply whether the technology can make data centers more efficient, but whether the promise of short-term efficiency gains can justify the long-term environmental risks that may follow.
(The official comment by environmental groups can be downloaded here. Publicly available documents regarding the Opteon 2P50 submission can be downloaded here. More information regarding the two phase immersion process can be found here.)