In Hong Kong, buildings account for 90% of the city’s total electricity consumption associated with 66% of carbon emissions. In the context of net zero by 2050, enhancing engineering innovations for building decarbonisation appears as an urgent imperative. The government, in concerted actions with key stakeholders, shall accelerate the development of smart sustainable buildings with a comprehensive set of sustainability performance criteria (with stringent reforms on embodied carbon of construction materials, and full retrofitting of existing buildings) that systematically integrate information technology and sustainability rating schemes throughout the whole life cycle of buildings.

In this process, engineering innovations towards zero-energy buildings are particularly crucial. Buildings must provide themselves with the direct use of solar energy—without photovoltaic (PV) panels, which are just convertors of the sunlight with extremely high carbon footprint—to significantly abate emissions relating to lighting / cooling / heating and all building systems. In fact, the total amount of solar energy that hits Earth in just two hours is more than enough to meet current global energy consumption for an entire year. Direct use of solar energy implies the development of buildings integrating sunlight transport systems with devices capable of channelling solar energy to the whole building envelope and services. The development of this technology which works with mirrored pipes, optical fibres, prism guides, lens guide systems, and acrylic rods, should be accelerated expeditiously in Hong Kong.

Based on recent studies, such an engineering revolution represents a great opportunity to achieve net-zero buildings associated with positive effects on human health, well-being and comfort. The main concerns to be elucidated are the effective capture, conversion and storage of such tremendous natural energy resources. Therefore, engineering research should focus on exploring a myriad of storage and conversion alternatives, including steam-driven turbines, storing in the heat capacity of a molten salt, or converting into hydrogen fuel, with particular regard to cost-effectiveness, affordability, maintenance and sustainability.

In sum, the potential of integrating smart sustainable buildings with zero-building energy undoubtedly paves a roadmap for the successful achievement of net-zero building in Hong Kong by 2050.

This article is contributed by Ms Rita Chu and Mr Eddy Leung under the supervision of Ir Dr Alex Gbaguidi with the coordination of the Environmental Division.