Harnessing Wind Power for a Cleaner Hong Kong

Have you seen the wind turbine on Lamma Island before? Lamma Winds is the first commercial-scale wind turbine commissioned by HK Electric in 2006.[1] As of mid-July 2023, the turbine has saved more than 12 million kilograms of carbon dioxide.[2]

Lamma Winds located at Lamma Island (Image source: HK Electric)

Wind power has emerged as a significant strategy for many governments to achieve net-zero emissions. Despite the head start, wind power development in Hong Kong has remained stagnant until recently. In 2022, renewable energy accounted for only 0.4% of the city’s electricity consumption, with wind power constituting just a small part of it.[3] Comparatively, in small cities like Rock Port in the United States and larger cities such as Copenhagen in Denmark, wind farms supply most, if not all, of their electricity needs. [4][5]

Still, Hong Kong is planning to develop offshore wind farms. CLP has proposed the construction of 17 wind turbines off the coast of Clear Water Bay to generate 255MW of electricity.[6] Meanwhile, HK Electric plans to build a 150MW wind farm near the Lamma Island in 2027.[7][8]The proposed offshore wind farms will employ conventional three-bladed horizontal-axis wind turbine designs, which are widely recognized for their high output power, efficiency and reliability.[9]

A preview of the proposed offshore wind farm at Clear Water Bay (Image source: CLP Power Hong Kong Limited)

Wind farm adopting three-bladed horizontal-axis wind turbines in the Netherlands (Image source: Electrek)

In China and the United Kingdom, offshore wind is rapidly maturing. In 2021, China completed the Jiangsu Qidong Offshore Wind Farm, the nation’s largest offshore wind farm. It is unique in that the turbines are placed far from the coast, enabling them to capture stronger winds. [10],[11]The London Array Wind Farm in the United Kingdom consists of 175 wind turbines,[12] and its massive scale generates a significant amount of electricity.

Location of the London Array Offshore Wind Farm in the United Kingdom (Image source: Metalocus)

Although the scale of proposed offshore wind farms in Hong Kong is limited by its territorial waters, the city can learn from the two examples. Hong Kong can take reference from the Qidong Wind Farm and consider siting the wind farms farther from the coastline. Additionally, the city can learn from the London Array and explore the placement of more wind turbines in specific locations to maximise the capacity of wind farms.

Despite the advantages of adopting conventional wind turbines in Hong Kong, there are factors that affect the effectiveness of electricity generation and the nearby environment. The region is occasionally affected by typhoons, where exceptionally high wind speeds could damage the turbines if they are not shut down.[13] Besides, the construction of fixed bottom turbines affects the nearby marine environment, resulting in a loss of subtidal soft bottom habitat.[14] However, there have been recent innovations to help address these issues, such as the floating vertical-axis wind turbine.

By combining floating wind turbine and vertical-axis wind turbine designs, the wind turbine can capture wind from different directions without the need for turbine rotation. Vertical-axis wind turbines are better equipped to withstand gale wind conditions, which are common in Hong Kong.[15]Besides, they have a smaller footprint, making them suitable for Hong Kong’s compact urban environment.[16] Floating wind turbines offer the advantage of being situated farther from the coastline, where deeper waters would make fixed-bottom wind turbines prohibitively expensive. Another advantage of floating wind turbines is that the gearbox and generator operate at the waterline with a lower centre of gravity, which reduces the substructure costs during turbine construction.[17]

Floating vertical-axis wind turbines in France (Image source: WindPower Monthly)

In other areas, researchers at Nanyang Technological University have invented a wind harvester that functions at low wind speeds.[18]The machine can generate electricity from wind speeds as low as 2 m/s, making it useful for powering low-energy electronics such as lights and commercial sensors.[19]Notably, the wind speed in Hong Kong’s urban area averages to around 9.9 km/h, or 2.75 m/s, between 1991 to 2020.[20]

The small-scale wind harvester can power low-energy electronics (Image source: The Straits Times)

Hong Kong still has a long way in achieving net-zero emissions. These wind power innovations could potentially serve as solutions to help increase the proportion of wind power in Hong Kong’s electricity mix and alleviate climate change.

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