22 October 2016
Currently, less than 0.2% of the electricity supply in Hong Kong comes from solar energy. Photo:
Currently, less than 0.2% of the electricity supply in Hong Kong comes from solar energy. Photo:

Why Hong Kong is ripe for a solar future

With solar energy accounting for a minuscule proportion of the electricity supply in Hong Kong, the government must focus on tapping the abundant sunshine in the city and new solar technologies.

With the long blistering days of the past few months, the summer of 2016 is set to enter the local record books as one of the hottest ever. Yet, almost all of the plentiful solar resources are going waste.

Currently, less than 0.2 percent of the local electricity supply comes from solar energy, which is substantially less than in the UK – which is not a notably sunny place.

In the UK, solar panels generated 50 percent more electricity than coal in May, a new – if unusually high – record that was achieved this year.

Given the challenges stemming from climate change and fast-depleting fossil fuel stocks worldwide, greener ways need to be sought to power Hong Kong.

In Hong Kong, solar electricity generation is a better renewable energy choice than wind farms because the latter are noisy and may be detrimental to wildlife. That said, generating even 10 percent of our electricity through solar power will require large tracts of green land to be covered with solar panels, which is difficult in a city like Hong Kong.

While land may be a problem, Hong Kong is however not short of buildings. Buildings can be used productively as part of the infrastructure to support the generation of solar power.

A number of government buildings and facilities run by NGOs such as schools have already installed solar panels on their rooftops. However, the amount of electricity generated this way is relatively small. To substantially expand the uptake of this technology across Hong Kong, it should be embraced by residential and commercial buildings.

For a start, solar panels installed atop residential buildings can generate electricity for the shared facilities in the buildings such as lifts as well as air-conditioning and lights in communal areas. Building management fees will fall as the rooftop solar panel system pays for the shared electricity. If the panels are of good quality, the maintenance costs will be low and should be minimal in the first few years of their lifespan.

And if there is solar energy to spare after satisfying the electricity needs of individual tenants, it can be fed back into the electricity grid in exchange for a feed-in tariff, which is a widely adopted method internationally to encourage uptake of small-scale renewable and low-carbon electricity generation technologies.

Hong Kong is not a big place, and it will not necessarily take long to cover rooftops with solar panels, which are readily available from the Chinese market. Just look at the large number of roof gardens that have been created in the past few years.

The public imagination of solar panel use has so far been about their application on flat ground or rooftops. However, what has seldom been considered is that the vertical surfaces of a building can also generate solar power through photovoltaic (PV) cells sandwiched between glass layers in windows.

PV cells can be made into semi-transparent strips to let light partially go through. While PV-integrated windows may only generate between 1/8 and 1/10 of the electricity sourced from rooftop panels, they provide additional installation area and can also reduce heat transmission with a special coating, hence reducing the need for air-conditioning and electricity use.

Locally, researchers are contributing to the worldwide effort to develop clean and renewable energy resources to replace fossil fuels. For instance, the Engineering Faculty at The Chinese University of Hong Kong has developed a low-cost, efficient and stable method of deploying PV cells and energy storage and management systems through a five-year “Smart Solar Energy Harvesting, Storage and Utilization” research project.

Solar technologies are fast maturing, and greater policy support is needed if the advances are to be translated into actual change.

To increase the uptake of solar energy in Hong Kong, the government should offer incentives such as lower taxes to electricity companies. State policy changes can lead to marked developments in the clean and renewable energy market, as evidenced by examples set by Germany and Japan in the past 10 years. Meanwhile, trial building-integrated PVs could be implemented in new buildings.

According to the International Renewable Energy Agency, electricity generation from solar energy worldwide will increase from less than 2 percent today to 13 percent by 2030, while the costs will fall by nearly 60 percent in the next 10 years.

With solar energy production set to remarkably grow worldwide and the effects of climate change becoming more acute, Hong Kong should actively invest in more renewable energy and storage to promote a cleaner, greener 21st century.

Lu Yichun, an assistant professor of the Department of Mechanical and Automation at The Chinese University of Hong Kong, is the co-writer of this article.

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An assistant professor of the Department of Electronic Engineering at The Chinese University of Hong Kong

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