Drivers whizzing by Bayfront Avenue would most likely miss it. Standing next to the towering Marina Bay Sands hotel is a boxy structure that could well be a mirage. Shimmering in the sunlight is a curtain of aluminium flappers seemingly dancing with the wind — a mesmerising sight that camouflages the cooling tower of the world’s deepest district cooling system in plain sight.
Underneath this tower wrapped in a screen by the artist Ned Kahn is a plant that produces chilled water, which is five storeys and extends to 25m deep. The only other sign of this round-the-clock operation is a silver-on-silver sign of the “Singapore District Cooling Pte Ltd” tucked underneath Bayfront Avenue. Located just steps away from the Helix Bridge and the ArtScience Museum, this rectangular plaque points towards an off-white door: the entrance to the underground facility that keeps Singapore’s business district cool in its tropical climate.
Quality spaces above
Traditionally, buildings have their own chillers and cooling towers on-site. But a district cooling system centralises them into an urban utility instead. The one at Marina Bay Sands is the second plant, the first one being at the One Raffles Quay development. They are connected together by a 5-kilometres network of pipes that pump cold water into the air-conditioning systems of buildings in the precinct, while receiving their warm water in return – a first in Singapore. Every hour, some 12,000 cubic metres of water chilled to 4.5 degrees celsius circulates around the network, just like the cars driving up and down Bayfront Avenue above.
Even as this cooling system brings the temperature down a notch in buildings such as the Marina Bay Financial Centre and Gardens by the Bay, it has also raised the district’s cool factor by freeing up space above ground for more quality and vibrant urban environments. It allows developers to achieve better building design and enhanced urbanscape without the need for cooling towers on rooftops, giving all developments in Marina Bay the freedom to use their rooftops for other uses. For example, Marina Bay Sands has turned their rooftop into an iconic space with an observation deck, an infinity pool and restaurants and bars serving up stunning views of the Singapore skyline.
Staying cool with less
What has also come down for building owners of Marina Bay is their energy costs. A centralised system means they do not have to pay upfront for their own chillers, but instead subscribe to a network designed and managed by the Singapore District Cooling Pte Ltd (SDC). According to this subsidiary of Singapore Power, its customers enjoy energy savings of more than 40 per cent, an amount which can power about 24,000 three-room HDB units a year.
The key to this is the plants’ thermal storage systems. Underneath Bayfront Avenue and Marina Bay Sands are six concrete ice tanks each measuring 20 metres high, stretching 10 metres wide and 12 metres deep. Holding almost 15,000 cubic metres of water (equivalent to three and a half Olympic size swimming pools), these tanks act like “giant batteries” that allow the system to cool buildings with fewer chillers that run on electricity. Instead, SDC produces and stores chilled water during the non-peak hours such as at night when electricity usage and tariff rates are lowerand discharges them to the buildings as and when required. In the event of an electricity outage, the tank even has the capacity to keep a large office building cool for 10 hours.
A uniquely Singapore solution for the world
The Urban Redevelopment Authority had identified district cooling as one of the several utilities, including electricity, water and telecommunications services that could be housed in a comprehensive common services tunnel for Marina Bay. The tunnel is a significant piece of infrastructure that planners have envisioned in the 1990s and catered for in their systematic mapping of underground space in Marina Bay. A first in South East Asia, the tunnel demonstrates how locating suitable uses underground can improve operating and environmental efficiency and free up land for a more vibrant environment above ground.
“We were venturing into new territory and it was a huge plunge into the unknown, particularly given the massive scale of this undertaking,” said National Development Minister Lawrence Wong at a ceremony earlier this month to officially commission the district cooling system’s operations. “If left to the market, this project would never have taken off.” To “de-risk” this project, the government took on an active role to formulate policies even before the system was laid. For instance, in 1998, the Energy Market Authority as the regulator for the DCS demarcated a 1.25 million square metres zone in the district for this pilot project. Within it, the agency made it mandatory for new developments within the pilot zone to take up the supply of chilled water. These laid the ground for Singapore’s first district cooling plant to be built at One Raffles Quay, which commenced operations in 2006 under the SDC, a homegrown venture established to implement this system.
Since then, the district cooling system in Marina Bay has steadily expanded its total capacity to 217 megawatts — the largest such underground DCS system in the world. It now serves many customers, three of which are One Marina Boulevard, Gardens By The Bay and Ocean Financial Centre, who chose to use the system even though it was not mandatory for them to do so, seeing the benefits of the system. Most recently, it also signed on Marina One at its commissioning ceremony, adding another 60 megawatts of chilled water capacity and increasing its overall capacity by a third. The upcoming Singapore Chinese Cultural Centre will also be tapping on the DCS supply. In addition, Singapore Power has taken its newfound capabilities overseas to Chongqing, China, where it is currently designing and building a similar system that it would eventually operate too.
With the success of Singapore’s first district cooling system, a similar one is now being explored for Jurong Lake District, the city’s next central business hub. An underground masterplan is also being developed to explore how Singapore can best utilise underground spaces for storage, utilities and infrastructure. Some examples that have started are the Jurong Rock Cavern and the Deep Tunnel Sewerage System.
Looking back on this decades-long journey to introduce district cooling to the city, Minister Wong attributed its fruition to the “uniquely Singaporean way” of a good public-private partnership. The result is an engineering feat that has not only improved the lives of Singaporeans, but also become a solution that can be exported to the world.
“It’s an illustration of how we all come together to achieve something quite incredible,” he explained. “This is an excellent example of what our Singapore story is about.”