Yves Hervouet dF

Waste heat from the world’s most powerful particle accelerator is now being used to heat homes nearby. At CERN, the Large Hadron Collider (LHC) is known for accelerating particles to nearly the speed of light and smashing them together to study the fundamental structure of the universe. Recently, however, the enormous machine has taken on a second role: providing heat to a neighbouring community. A new heat-recovery system captures excess heat produced by part of the collider’s cooling network and transfers it to buildings in the French town of Ferney-Voltaire. The LHC runs in a circular tunnel about 27 kilometres (17 miles) long beneath the border between France and Switzerland. Many components of the accelerator must be kept cool at all times to function properly, so water constantly circulates through cooling systems. As this water absorbs heat from the equipment, it gradually warms up. Previously, that heat was simply released into the air through cooling towers. Now, instead of being wasted, the warmed water passes through heat exchangers that transfer its energy into the town’s district heating system. At present, the system can deliver up to 5 megawatts of heat, which is enough to help warm the equivalent of several thousand homes and businesses. With two heat exchangers in place, the output could eventually reach 10 megawatts once the accelerator is fully running. Reusing this energy reduces the need for heating powered by fossil fuels. Officials estimate the project could prevent thousands of tonnes of carbon dioxide emissions each year. The initiative is part of CERN’s wider plan to make large scientific facilities more sustainable. Through several energy-recovery projects, the organisation aims to save around 25 to 30 gigawatt-hours of energy annually by 2027.