How much do particle accelerators pollute? The CERN study

It is called FCC, an acronym for Future Circular Colliderand, if and when it is actually built, it will be the greatest particle accelerator in the world. Even bigger than Lhc, the instrument with which the scientists of CERN in Geneva managed to identify the Higgs boson ten years ago, which with its 27 kilometers of circumference is not small. But in the design of the new accelerator, not only the dimensions count: physicists and engineers are in fact starting to take into account theenvironmental impact resulting from the construction and operation of such large and complicated machines. Almost a duty, when the great of the Earth are gathered in Egypt, to the Cop27to discuss the climate and energy challenges of the planet.

A study just published in the journal The European Physics Journal Plus, signed by CERN experts, has assessed the energy consumption and environmental impact of different types of particle accelerators, showing that the current FCC project is actually the most “sustainable”, since it should only consume one sixth of the energy compared to other projects. Not a bad saving, in short.

Accelerators such as Lhc and Fcc are considered “Higgs factories”, precisely by virtue of the fact that they are able to produce Higgs bosons with which one tries to study and characterize the new physics. The Fcc alternative Higgs factories considered in the newly published study are the Circular Electron Positron Collider (Cepc) Chinese, lo International Linear Collider (Ilc) Japanese, the Compact Linear Collider (Click) of Cern and the Cool Copper Collider (C³) US (Ilc, Clic and C³ they are linear accelerators, unlike Lhc, Fcc and Cepc which are circular): scientists have evaluated their environmental impact considering how much energy they would consume, on average, for each Higgs boson produced. “This choice makes sense”, commented a Nature Patrick Janot, CERN physicist, “because the possibility of making new discoveries is directly linked to the number of Higgs bosons produced”. In general, circular accelerators tend to have an annual energy consumption similar to that of linear accelerators, but they generate Higgs bosons faster, so in theory they can “produce” more science in less time.

And here are the numbers: according to the analysis, FCC would consume about 3 megawatt hours of electricity for each Higgs boson produced, followed immediately after by Cepc with 4.1 megawatt hours. Linear accelerators perform slightly worse, and the ranking is closed by C³ with its 18 megawatt hours per boson. However, it must be taken into account that there are also other environmental costs not included in the analysis, including the emissions deriving from the construction of the new structures and the decommissioning of the previous ones and from those deriving from the detectors.