ra4 1

Two joint studies for public policy research by Dr Charles Wong of the Department of Land Surveying and Geo-Informatics (LSGI) and Dr Lin Lu of the Department of Building Services Engineering (BSE) have found that about 75% of buildings’ rooftops in Hong Kong were suitable for implementing solar photovoltaic (PV) systems. If they were all installed for that purpose, they could supply about 10% of electrical power for the city’s consumption, reducing 3 million tons of greenhouse gas emissions from local power plants accordingly every year.

Beginning in 2013 and lasting for more than 2 years, the study used geographic information system and remote sensing technology to calculate the buildings’ overall potential for generating electricity based on an estimate of the unused building rooftop areas that could be installed with solar PV systems. Not only did the study find that 40% to 50% of days in 2013 were sunny in Hong Kong, it also noted the feasibility for more than 230,000 buildings here to take advantage of solar PV systems. The total surface area of the buildings’ roofs was between 2,800 and 3,900 hectares, which is the equivalent of 147 to 200 Victoria Parks.

According to Dr Wong, the utility rate of the rooftops of commercial buildings along the harbour from Central to Wanchai, as well as those of several landmark structures such as the Cultural Centre, for installing solar PV boards could be as high as 90%. Dr Lu added that the electricity cost from roof-mounted solar PV systems is still expensive due to high local installation costs, the energy return on investing in rooftop solar PV systems is 3 years at most. Based on the 25-year life-span of a solar PV module, it is estimated the electrical power generated after the first 3 years will be free and will not have any pollution associated with it. Moreover, Dr Lu said the Hong Kong government could consider opening the market for solar PV systems from the mainland to reduce their installation costs. The study has been widely reported in the local press such as Ming Pao Daily News, Sing Tao Daily, and Ta Kung Pao.