Singapore Brings Back 19th-Century Tech to Beat Warming Climate

Pipes carrying water from Engie's district cooling network in the Punggol area in Singapore. Photo by Stephen Stapczynski /Photographer: Stephen Stapczynsk

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(Bloomberg) — Deep underneath Singapore’s northeastern district of Punggol, a five-kilometer network of metal pipes roars as it pumps chilled water to cool offices and classrooms overhead.

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The 140-year-old concept known as district cooling is taking root in the tropical island-nation, where temperatures are rising twice as fast as the global average and sharpening the focus on climate adaptation. That the old technology uses less electricity than centralized air conditioners is a major advantage for a resource-starved country that has to import nearly all its energy.

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The city-state has laid such pipes beneath at least eight neighborhoods so far, with the Marina Bay network — the world’s largest underground system — having begun operations in 2006. More buildings will be linked up to that system, and separate facilities are being rolled out in other parts of the city by firms like Keppel EaaS Pte.

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The rollout comes as energy security takes center stage in countries, including Singapore, that are reeling from energy shortages caused by the US-Iran war, while also bracing for an exceptionally hot summer due to a projected “Super El Niño.” District cooling is a solution that’s gaining traction around the world, particularly in the Middle East, and is projected to grow to a $60 billion market by 2034 by one estimate.

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“Cooling demand is rising with urbanization, income growth, heat stress and commercial floor-area expansion” across Southeast Asia, said Lee Poh Seng, professor and head of mechanical engineering at the National University of Singapore. Singapore’s playbook will be important if it can “demonstrate district cooling systems that credibly deliver energy, water, carbon, comfort, reliability and economic performance under hot and humid conditions,” he said.

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The local market for the technology could double over the next decade from about 323,000 refrigeration tons today, according to Engie SA, which is among the world’s largest operators of such facilities. The firm runs two systems in Punggol district capable of cooling about 8,000 public housing units. It also sees potential to double district cooling capacity in Singapore, Malaysia and the Philippines by the next decade, said Jacques Boonen, Engie’s managing director for local energy infrastructures in Southeast Asia.

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Singapore has among the highest per capita use of air conditioners in the Asia-Pacific region, meaning it’s stuck in a negative feedback loop as the machines themselves release climate-warming emissions that create the need for more cooling. But the government is keen to kick the habit in favor of more efficient solutions, devising a S$100 billion ($77 billion) plan to safeguard the city against rising temperatures and sea levels. District cooling is part of those efforts. 

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The technology itself is relatively simple. Large tanks full of refrigerants chill water down to about 7C (45F) degrees; the cold water is piped into heat exchangers in buildings where warm indoor air is cooled when it passes against the liquid; the cooler air is then blown back out through air vents. As the water warms, it’s pumped back to the central plant, with excess heat released through a cooling tower.