Jill Baker reports on how air conditioning is one of the biggest energy efficiency challenges in a region that is home to the world’s hottest and most crowded cities

Singapore developer City Development Limited’s Tree House Condominium won a spot in the Guinness Book of World Records in 2014 for the world’s largest vertical garden.

It was one of many accolades for the 429-unit eco-inspired condominium, which features a vertical garden along its southern face that naturally cools the master bedrooms, screening them from the sun and filtering the air.

Everybody is talking about climate change. We are a little ahead of the curve

Green innovations comprised about 2.7% of the total construction cost, translating into an estimated annual energy saving of over 2.4 million kilowatt hours (kWh) and water savings of 30,000 cubic meters.

“Everybody is talking about climate change. We are a little ahead of the curve,” says Esther An, CDL’s chief sustainability officer. “In Singapore, we are the only developer that has achieved 100% ‘green lease’.” This is a scheme through which developer and tenants target efficiency goals and share the savings.

Increasing numbers of Asian developers are building more energy-efficient buildings. But progress remains slow. Green buildings, specifically those with net-zero energy design, are rare. What happens in Asia matters for the world. Home to about 60% of the world’s population, and 21 of the world’s 35 megacities, urban clusters with over 10 million people; Asia is urbanising fast.

CDL's eco-inspired Tree House condominium in Singapore. (Credit: CDL)

Energy efficiency is not valued highly by the Asian property market in general. Traditionally, Asian property developers focused on building and selling rather than looking at costs over the building’s lifecycle, according to Constant Van Aerschot, Asia Pacific director of the World Business Council for Sustainable Development (WBCSD). In Asian cities, buildings often account for a higher percentage of greenhouse gas (GHG) emissions than the worldwide average, meaning that efficiency improvements are vital if countries are to reach their climate targets. Buildings alone accounted for more than 70% (28.8% from residential and 44% from commercial) of Tokyo’s total carbon emissions in 2016.

In Hong Kong, the built environment’s share of GHG emissions is a little over 60%, according to the Hong Kong Business Environment Council (BEC). A substantially more efficient built environment will be essential for Hong Kong to play its part in meeting China’s nationally determined contribution (NDC) or its pledge to cut emissions under the Paris climate accord. Hong Kong aims to reduce absolute carbon emissions in 2030 by between 26% and 36%, relative to 2005 levels.

If that is to be the case, the building sector has a lot to do. The BEC notes that the energy intensity of office buildings fell by almost 25% between 2002 and 2008 due to special incentive schemes giving extra gross floor space to commercial developers who met the territory’s BEAM Plus energy-efficiency standards. But reductions since have been negligible, and the energy intensity of private residential buildings has not declined over the period. (See Why 31 companies have joined forces to decarbonise Hong Kong's building sector)

In Asia’s hot, crowded cities, ventilation is an afterthought, and external solar shading is costly and often banned

China and India will constitute the lion’s share of new buildings growth in Asia, driven by the rise of the middle class and urbanisation. According to a report by the WBCSD, China is adding buildings at a rate of 2 billion square metres a year, equivalent to one-third of Japan's total building stock. If building energy consumption in China and India grows to current US levels, their consumption will be, respectively, about four and seven times greater than they are today.

Asia’s building energy-efficiency problem is heat, with air conditioners driving up electricity use.

In most Asian countries, with the notable exception of Singapore, building codes are just beginning to pay rigorous attention to the insulating properties of the building envelope.

High-performance glazing is not generally used in Asia's skyscrapers. (Credit: Pan Xunbin/Shutterstock)

Without them, structures are often built to serve the short-term needs of developers rather than taking a lifecycle approach to energy efficiency.

The potential energy savings for standard buildings from insulation is very different for heating than for cooling. “Savings of around 80% for heating are relatively easy to achieve in new construction, while savings on cooling are a lot more difficult,” according to the WBCSD’s Van Aerschot. “Most energy savings for cooling are to be found in better air conditioning systems.” But these offer improvements of only 10%-20%.

In cities, windows often don’t open, forcing more use of air conditioning. Traditional Asian houses built for tropical and sub-tropical environments used shading, orientation and airflow to shelter and cool their inhabitants from the tropical sun. Today, in Asia’s hot, crowded cities, ventilation is an afterthought, and “external solar shading [to reduce heat gains] is costly and often banned by regulation for safety reasons [due to high wind loads],” Van Aerschot said.

Even though high-performance glazing exists, it is not really used at a large scale due to costs

The results are skyscrapers with energy-inefficient glazed glass towers. “Even though high-performance glazing exists, it is not really used at a large scale due to costs,” Van Aerschot says. Global energy demand for heating and cooling buildings shows very different trends. Heating flattens out, while energy use for cooling slopes steeply upward, driven by megacities, many of them in Asia. Often, residential buildings in Asia lack centralised air conditioning, relying on inefficient individual air conditioning units. The fitting remains with the new owner of the flats, so property developers, especially in China, Van Aerschot says, simply don’t invest in cooling.

Singapore is modelling best practices for the Asian built environment. The World Economic Forum has classified it as one of the 10 Asian cities “most prepared for the future”. The island city is working hard at both a government and enterprise level to tackle climate change and has pledged in its Paris NDC to reduce its greenhouse gas emissions intensity per unit of GDP by 35% from 2005 levels, and to have its emissions peak by 2030. The government is using regulation to respond to the urgent threat of global warming: Singapore’s rate of temperature rise is more than double the global average according to its NDC.

These temperature increases are due to larger-scale GHG emissions and the local “heat island” effect directly resulting from Singapore’s urbanisation. At night, the difference between downtown Singapore and the forested region of Lim Chu Kang, 25km away, can reportedly exceed 7C.

Even improved air conditioning units only offer 10-20% energy savings. (Credit: Alex Marakhovets/Shutterstock)

The city’s Sustainable Singapore Blueprint declares that greener new builds and retrofits of buildings are some of the most effective ways for a city to reduce its overall carbon footprint. Singapore’s pioneering Green Mark standard is now more widely used in Asian countries than the US Green Building Council’s LEED standard, and Singapore aims to have 80% of its building stock achieve Green Mark standards by 2030.

Green Mark certifies a building at four levels, the highest of which is platinum. Unlike LEED, Green Mark was developed by a government, not an industry association, and is designed to achieve specific policy aims such as reducing energy and water consumption. Particularly well-suited to tropical and sub-tropical environments, Green Mark has evolved to include more emphasis on passive design and sustainable construction materials as well as on the well-being and comfort of building occupants.

Singapore’s third Green Building Masterplan, published in 2014, uses market-based incentives for retrofits of existing buildings and for new builds to conform to platinum Green Mark standards. Incentives such as gross-floor-area bonuses and financing are designed to encourage both owner and tenant participation.

We look at the potential threats to individual buildings in specific locations and those together make up the financial impact. It involves a lot of 'what ifs'

Esther An, of CDL, says the property developer has lifecycle building efficiency measures across its 18 million square foot portfolio of commercial and residential buildings. All new CDL developments must be Green Mark GoldPLUS certified, two tiers above the mandatory Green Mark certification level.

It has adopted carbon emissions intensity reduction targets of 59% by 2030 from a base year of 2007, and is the only south-east Asian company to have its carbon reduction targets validated by the Science Based Targets initiative (SBTi).

In early 2018, CDL embarked on a climate change scenario analysis, quantifying the impact of a 2C and 4C warming scenario, based on Task Force on Climate-related Financial Disclosures (TCFD) recommendations.

“We look at the potential threats to individual buildings in specific locations and those together make up the financial impact. It’s a very complex process,” Esther An said. “It involves a lot of ‘what ifs’, because no one really knows what will happen by 2030. But it’s what we must do to climate-proof our portfolio.”

Singapore is one of the 10 Asian cities ‘most prepared for the future’. (Credit: CDL)

Esther An says innovation is crucial. “Now, we set our carbon reduction target at 59% adopting SBTi and incorporating Scope 1, 2 and even indirect Scope 3 GHGs. We are very honest in saying if we were using just today’s technology and practices, we would not be able to achieve 59%. But we are pushing very hard on technology and also practices. We have 10 more years to go and we will push hard, we will continue using the very best we have to harness our technology, harness our new practices, harness our green energy to reduce by 59%.”

In 2017, CDL worked with Sustainable Energy Association of Singapore to open Singapore Sustainability Academy (SSA), a net-zero energy building, showcasing state-of-the-art efficiency building materials. Esther An describes the SSA as “a hub for knowledge sharing, capacity building and partnership on ESG”.

Powered by solar and constructed from cross-laminated timber (CLT) and glulam, two forms of fabricated sustainable timber that are both lighter and less GHG intensive than steel or concrete, SSA will be a platform for CDL’s Women4Green initiative, bringing together women executives to empower other women to incite meaningful change in green building, technology and energy.

For now, CDL is the exception, but by 2030, these sorts of efforts are likely to be routine, in Singapore and elsewhere in much of Asia.

Jill Baker is an adjunct fellow at the Hong Kong-based Asia Business Council, and is research adviser at Terra Alpha Investments. She was the principal researcher for The Greening of Asia: The Business Case for Solving Asia’s Environmental Emergency (Columbia University Press, 2015).

Main picture credit:  Luciano Mortula/Shutterstock


This article is part the in-depth Built Environment Briefing. See also:

22 cities at vanguard of global drive to cut climate impact of buildings

Why the buildings sector needs a LED light bulb moment

Salesforce thinks big to cut its water impact

Building sector takes concrete steps to address ‘hidden’ emissions

Getting to the bottom of the green buildings conundrum

Leading companies partner with London in zero-carbon push

Good for the planet, good for the people

The design standard with people at its heart


CDL  Singapore  sustainable building  energy-efficient buildings  Hong Kong Business Environment Council  Green Mark certification 

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