Constructing a green, sustainable future

Hong Kong's aiming to go carbon neutral by 2050, but an all-out effort is needed to ensure its buildings measure up to exacting green standards. William Xu reports from Hong Kong.

Buildings shelter us from harsher side of nature, soothe our tired minds, and create productivity in the community.

Hong Kong's high-rise buildings, constructed with steel and concrete, showcase the city's economic miracle in a narrow terrain. But as the special administrative region begins charting a road map to achieve its carbon neutrality goals with more electric-powered vehicles, renewable energies and a comprehensive waste recycling system, an overall green transition of buildings has yet to be realized among enterprises that commit themselves to cutting greenhouse gas emissions.

Power generation is responsible for nearly 63 percent of Hong Kong's greenhouse gas emissions, with more than 90 percent of the electricity supplied to all kinds of buildings. Explicitly, the financial hub's 50,000 or so government and private buildings are prime culprits in emitting greenhouse gases.

Despite the tremendous load these buildings have placed on the SAR's net-zero emissions target, many of them are still on the sidelines waiting to hop onto the decarbonization bandwagon. So far, just over 8,100 local buildings have been certified, or are in the process of being classified as "green buildings" under BEAM Plus - a set of criteria introduced to measure a building's sustainability performance, including its use of materials and design.

Launched by the Hong Kong Green Building Council in 2010, BEAM Plus has emerged as one of the city's most popular green building rating tools. It assesses existing buildings or those that are being built, with regard to their planning, design, construction, operation and maintenance, and rates their sustainability performances in four grades from good to weak - platinum, gold, silver and bronze.

As an incentive for promoting green buildings, the Buildings Department added the registration for BEAM Plus assessment in 2011 as a compulsory requirement for developers seeking gross floor area concessions - a program that allows them to apply for up to 10 percent of extra construction area in compensation for land taken up by facilities for the benefit of public and environmental protection, such as common corridors and gardens.

In pursuing "green architecture", Cheung Tin-cheung, chairman of the HKGBC, stresses that it's not telling people to keep switching off lights or air conditioners. "We're not trying to bring down our quality of life. We're seeking more energy-efficient ways to maintain a comfortable environment." For example, it's possible to have air conditioners and fans switched on at the same time to lower room temperature, while reducing energy consumption, he says.

Apart from interior design, BEAM Plus also assesses whether a construction site or a completed building has a negative effect on its surrounding environment. "Let's say, whether a building will weaken the ventilation of the block in which it's located," says Cheung, adding that green buildings should also focus on using renewable building materials and harmless disposal of construction waste.
Hong Kong's designers and architects have already turned their vision of green buildings into reality.

Zero Carbon Park is Hong Kong's first building that can operate without emitting greenhouse gases. Built in 2012 by the Construction Industry Council, the park, located in Kowloon Bay, is tasked with boosting the public's awareness of a low-carbon lifestyle and, more importantly, demonstrating the feasibility of zero-carbon building.

Unlike traditional approaches focusing on saving energy, the park, alternatively, turned to the forces of nature to lower residents' demand for electricity.

In the park's main building - a two-story exhibition hall - several fans were installed on the ceiling to cool indoor spaces. The fans are specially designed to generate high air flows with low noise. On the floor, small holes with metal covers supply the building's rooms with air extracted from the cooled underground areas. These unplugged "air conditioners", with motor-controlled windows, help maintain the indoor temperature comfortable with less energy consumption. Brightening up the park are dozens of solar panels on the exhibition hall's rooftop and biodiesel.

Suitable approach
Ten years after Zero Carbon Park opened, Hong Kong's zero-carbon goal is prompting more designers and builders to embrace the green transition. "In the early stages of BEAM Plus, only 40 percent of projects received a gold grade or higher. This year, about 70 percent of projects have secured gold and platinum grades," Cheung reveals, calling the shift a "testimony" to the city's growing demand for greener buildings.

Among the building projects that have registered for BEAM Plus assessment, nearly 76 percent concern new buildings. As for existing buildings, the road to decarbonization may be much longer.

Many of Hong Kong's high-rise commercial and residential towers sprang up during the construction boom before the 1990s. The number of private buildings over 50 years old had doubled to 9,600 as of late November, compared with a decade ago, and accounts for nearly one-fifth of the city's total buildings. Each year, a further 600 local buildings become 50 years old.

The lighting and air-conditioning systems of aging buildings often lack energy-efficient features, and their exterior walls are, generally, poorly insulated and soundproofed, says Cheung.

Working with property developers, the Urban Renewal Authority redeveloped 1,650 private buildings between 2013 and 2022 - at a pace far behind the aging speed of buildings. For most existing buildings, energy-saving renovation would be a more practical way to cut carbon emissions.

Neutron Digital - a technology company based in Hong Kong Science Park specializing in smart buildings - has developed a set of real-time computer tools to identify energy waste in buildings and provide optimization recommendations.

Mark Chen, Neutron Digital's chief technology officer, says they reviewed the chiller system at an office building of more than 20 years old, using its self-developed system. With data collected from other public facilities in the building, as well as additional data sources, and artificial intelligence analysis, the system generated real-time energy management recommendations that could save 8 to 15 percent of energy consumption.

"In the past, builders always prioritized buildings' smooth operation during high load conditions," says Wang Shengwei, chair professor of building energy and automation at the Hong Kong Polytechnic University. "Energy efficiency was often not an important factor for consideration." When designing a building, its facilities, such as light bulbs and elevators, are by default at their full capacity in order to maintain the smooth operation at any time. This could result in energy waste when these facilities are not being fully used most of the time, he says.

Powered by AI and big data technologies, a power optimization system developed by Wang's team provides tailor-made solutions for different buildings to boost energy efficiency. "Unlike industrial products, each building has its unique design, so there's no one-size-fits-all solution," says Wang. The power optimization system has aided various construction projects, having helped the 118-story International Commerce Centre in West Kowloon - at 484 meters Hong Kong's tallest skyscraper - to save about 10 million kilowatt-hours of electricity each year. Public facilities have also benefited from the system, with PolyU's Phase 5 buildings consuming 38 percent less in energy. "Energy saving can start at any time of a building's life cycle," he says.

Some of Hong Kong's oldest buildings have also begun to decarbonize. Along Argyle Street in Mong Kok towards Shanghai Street, there's a cluster of multistory arcades occupied by eateries, bistros and boutiques. Most of the arcades were built in the 1920s as shophouses, which have given way to new commercial centers before being redeveloped into a downtown leisure destination in 2019.
The buildings' rebirth reflects how green mindsets have been embedded in their revitalization. The air conditioners, light bulbs and elevators are outfitted with energy-efficiency technologies, resulting in a 32 percent reduction in the overall energy consumption. The indoor temperature is maintained at a comfortable level as glass windows with a low shading coefficient mounted on the exterior walls are more effective at blocking sunlight.

More than 40 percent of the project's roof and the facades of the higher floors are covered by greenery to mitigate the "heat island effect". These sustainable designs and applications helped the project win a BEAM Plus platinum grade in 2020.

Concerted effort
However, some property owners have refused to shoulder the extra costs that come with green renovation. Old buildings may have technical and structural limitations that hinder the application of green technologies, resulting in higher costs and longer improvement work, explains Chen.

In 2018, the SAR government adjusted the voluntary Energy Efficiency Registration Scheme for Buildings. Since then, the program has offered a one-time tax deduction, instead of the usual five-installment arrangement, for expenditures on energy-efficiency facilities in buildings with an energy performance exceeding the minimum requirements under the Buildings Energy Efficiency Ordinance and recognized by Beam Plus or international assessment systems.

CLP Group - one of Hong Kong's two power suppliers - established the Eco Building Fund to subsidize up to 400 commercial, industrial and residential buildings a year for their energy-saving improvement works. Each building can receive a maximum subsidy of HK$500,000 ($64,060) per year.

The Smart Power Building Fund, initiated by the city's other power supplier, Hong Kong Electric, sponsored property owners in enhancing the energy efficiency of communal building services installations. For ordinary residential buildings, the subsidy rate is 50 percent, capped at HK$400,000, within five years.

Cheung says another key element in existing buildings' green renovation is a consensus among the occupants. He suggests that improvement works can start from some easy-to-complete areas, such as optimizing the operation of mechanical and electrical devices, which can also bring in immediate economic paybacks as electricity consumption is reduced. "It's important to let people know the benefits of the renovation works."

Hong Kong aims to cut 40 percent of energy consumption by 2025 from the 2005 levels, according to the Energy Saving Plan for Hong Kong's Built Environment (2015-2025+) published in 2015.

The Environment and Ecology Bureau told China Daily the SAR government is committed to attaining its 2050 targets - cutting power consumption in commercial buildings by 30 to 40 percent, and in residential buildings by 20 to 30 percent from the 2015 levels. The administration hopes to achieve at least half of the goals by 2035 or earlier.

Chief Executive John Lee Ka-chiu said in his second Policy Address that amending the Buildings Energy Efficiency Ordinance will be a priority of the government's work next year to further promote buildings' decarbonization.

The HKGBC has urged the authorities to include more types of buildings, including those with high power consumption, such as data centers, in the ordinance. It also calls for wider disclosure of more energy-related information to encourage participation in energy-saving retrofitting, and shorten the energy audit interval from the current 10 years to five years.

Policy support may also be conducive to speeding up the green transition. For instance, France has launched a two-step strategy to improve energy efficiency in all its buildings across the country, with 500,000 buildings due to be renovated every year until 2030, and 700,000 annually between 2030 and 2050.

In the capital, Paris, local authorities can compel property owners to conduct energy audits and renovations. For example, the government will prohibit owners from renting out a building if it is found to consume an average of more than 450 kWh per square meter a year.

The HKGBC emphasizes that green finance is crucial for the decarbonization of buildings. According to Cheung, global companies now have higher ESG (environmental, social, and governance) standards in aspects of property investment and rental. Investors' mounting demand for green buildings will definitely push Hong Kong's construction industry to act, he says.

The SAR's concrete jungle is still growing to cater to its development needs. But the expansion cannot be built on the basis of undermining the city's perseverance in creating a zero-emissions future.

The government, stakeholders and all residents must be at one in the city's drive for carbon neutrality - a greener roof would bring better and more sustainable living conditions for all.

Contact the writer at williamxu@chinadailyhk.com