Hong Kong is a subtropical coastal city, with the region covering 1106 km2. It is home to 7,482,000 people, and has a GDP US$338 billion (Hong Kong Gov, 2021). Although the population density isn’t one of the highest at 6,750 person/km2, Hong Kong is the city with the greatest number of skyscrapers in the world, with 6 buildings over 300m tall, 84 buildings over 200m, and 482 over 150m (CTBUH, 2021). In the post-war period, Hong Kong saw rapid development and became one of the fastest growing global economies (Chung et al., 2018). As the city developed, it became highly commercialised, with over 93.4% of its GDP originating from commercial services with the remaining falling under industry in 2020 (Hong Kong Gov, 2021). This is exemplified in how the sectoral energy consumption has evolved over the past two decades (Fig. 1), where absolute energy consumption has halved for industry, whilst commercial and public services have increased by 2.5 times, and residential consumption has doubled (IEA, 2021). Energy consumption per capita has also increased considerably over this development period (Fig. 2), and could potentially rise further under a warmer future climate, with an increase of almost 10% in energy demand for residential sector and 3% in commercial sectors (Fung et al., 2006).

Figure 1: Sectoral energy consumption in Hong Kong, measured in kilo-tonnes of oil equivalent (IEA, 2021)

Figure 2: Historic electricity consumption per capita in Hong Kong (IEA, 2021)

Historically, this demand was met primarily with coal and oil, with natural gas introduced in the late 1990s (Fig. 3). Hong Kong’s current ambition is to phase out coal and replace it with more natural gas (Fig. 4). Natural gas can emit approximately half the GHG emissions per kWh generated when compared with coal (Agrawal et al., 2013). Although this GHG/kWh efficiency gain has been scrutinised, as it is thought that methane leakage from natural gas infrastructure could eliminate the GHG reductions (Lenox and Kaplan, 2016; Lelieveld, 2005; Alvarez et al., 2012; Pandey et al., 2019), however, there are other benefits to the use of natural gas over coal such as reduction in pollutants (PM2.5, CO, NOx, CH4), reduction in mortality rates and increases in agricultural yield (Zhao et al., 2018; Wang et al., 2020; Burney, 2020).

Figure 3: The breakdown of electricity generated within Hong Kong by fuel type (IEA, 2021)

Figure 4: The Hong Kong Government’s tentative plan to reduce coal consumption by utilising more natural gas, and expanding non-fossil fuel sources where possible (Hong Kong Gov, 2017)

The heavy focus on natural gas could be due to Hong Kong’s limited potential for local renewable energy generation. Currently, renewable energy makes up < 1% of electricity consumed, consisting of wind, solar and waste to energy (WTE) systems (IEA, 2021). The Hong Kong government estimates that only 3-4% of their energy demand could be met by these renewable technologies by 2030 (Hong Kong Gov, 2017). In the Climate Action Report, they cite barriers such as intermittent output of renewable energy, with issues such as “cloudy days, or where panels are occasionally shaded”, as well as the “considerably more expensive cost” over natural gas (Hong Kong Gov, 2017). Despite the limited plans to harness wind power, there have been numerous studies identifying sites around Hong Kong for installations, both offshore and on land (Gao et al., 2014; Shu et al., 2015; Lu and Yang, 2001; Shu et al., 2015) as well as systematic approaches to make it more cost competitive (Sun et al., 2019; He et al., 2020). Photovoltaic (PV) solar panels are also limited in their current application, with the majority of installations being small scale additions to existing buildings (Hong Kong Gov, 2017). Studies on the feasibility of PVs generally find that there is a lack of incentives, legislation, regulation and subsidies for the use of solar panels (Zhang et al., 2012; Ngar-yin Mah et al., 2018), highlighting a potential lack of engagement with PV usage from the government. Although not ruling out solar generation entirely, the government highlights potential routes to utilise space on tall buildings (Hui et al., 2017; Lu and Yang, 2010; Zhang et al., 2017). Whilst this may help alleviate the high future energy demand, it is unclear how much of a part they would place at city-wide reductions.

The majority of Hong Kong’s non-fossil fuel electricity is imported from the Daya Bay nuclear energy plant in Shenzhen, providing almost a quarter of all of Hong Kong’s consumed energy (Dou et al., 2021). Nuclear energy is generally perceived as being effective in reducing GHG emissions, although the long-term benefits may favour renewable energy generation (Jin and Kim, 2018). Furthermore, there can be challenges surrounding the perception of nuclear power plants, largely focused on the risks involved following previous disasters (De Groot and Steg, 2010; Stoutenborough et al., 2013; Ho et al., 2018). This is true for Hong Kong too, where the nuclear energy policies are seen as controversial by residents (Kwok et al., 2017; Ngar-yin Mah et al., 2014). The current arrangement for imported electricity is due to expire in 2024, and there are currently no plans in place to renew it (Hong Kong Gov, 2017). The tenuous relationship between Hong Kong and mainland China also draws into question how much the region can rely on Chinese imports, particularly as further cooperation with mainland China is viewed as an unpopular option (Holley and Lecavalier, 2017).

Given these challenges, Hong Kong’s aspiration is to phase out coal entirely, replace it with renewables where possible and otherwise natural gas (Fig. 4). There have been no new coal plants built since 1997, and since 1996, 10 natural gas fuelled stations have been constructed, with further developments citing improved efficiencies (Hong Kong Gov, 2017). Although there are various programs in place to study sites for renewable energy, there are currently no planned large-scale developments.

Given the outlined challenges on generation and importation of energy, Hong Kong’s Climate Action Plan also highlights the efficiency of buildings and infrastructure. In 2017, 63% of GHG emissions came from electricity generated for buildings (Hong Kong Gov, 2017). Alongside the Climate Action Plan, Hong Kong’s Environmental Bureau published the Energy Saving Plan in 2015, which is a report on reducing the energy intensity of the built environment. The main goal of this plan was to reduce energy intensity by 40% by 2025, using 2005 as a baseline (Hong Kong Gov, 2015). The definition of energy intensity is given as energy demand per $ GDP. As a result, although GHG emissions have increased, and energy consumption in total and per capita has increased, the energy intensity for Hong Kong has decreased as per their target, largely due to the doubling of GDP over the past 15 years (World Data Bank, 2021). As a metric, Hong Kong’s energy intensity performs better than a number of other countries, partially due to its density and rapid commercialisation (Fig. 5).

Figure 5: Energy intensity of Hong Kong in comparison to other regions and countries, measured as tonnes of oil equivalent, per 1000 US dollars using 2010 purchasing power parity (IEA, 2021)

The routes to achieving energy reductions generally focus on broad scale strategies: educating the public, supporting communities to be more energy efficient and increasing the frequency of reviews of key energy standards such as the Buildings Energy Efficiency Ordinance – BEEO (Hong Kong Gov, 2015). The plan has more specific goals too, such as achieving a 5% electricity usage reduction in government buildings by 2020 (with 2014 as a baseline), and the requirement of new government buildings to achieve BEAM Plus Gold, the second highest award for a commercialised sustainability accreditation scheme for buildings in Hong Kong (Hong Kong Gov, 2015). However, as a whole, the report focuses mostly on historic and current energy use in Hong Kong, with much smaller portions laying foundations for clear energy reduction strategies and targets. In the conclusion, the report admits that the 40% reduction target “is less than what some advocates have called for but this level of reduction is not without ambition. Our assessment is the public has the capacity to take responsibility to save energy but has yet to take greater action.” It’s indicative of a more passive stance from the government to achieving reductions in the private sector, opting to impose stricter regulations primarily on governmental and public buildings, whilst relying on existing regulations (e.g., BEEO) to incrementally improve the private sector. Historically this approach has seen successful improvements in building efficiencies, with a number of developments operating with improved energy use from 2004-2013 (Jia and Lee, 2018). The main drivers for these changes were attributed to various government policies, including the energy standards, and the BEAM accreditation.

The Climate Action Plan builds upon this foundation, advocating various strategies to reduce energy consumption in buildings, such as greater transparency of energy usage through declaration in a centralised database. This transparency has the potential to increase competitivity between building owners, to achieve greater energy efficiency (Mol, 2015). They also continue to highlight the importance of public engagement, to improve the knowledge of builders and owners, and encourage the use of more efficient systems such as Fresh Water-Cooling Towers, which have proven efficacy in reducing energy consumption (Jia and Lee, 2018).

Another benefit of improving energy efficiency is that the improvements are generally passed directly to the tenant or building owner in the form of cost savings: whilst some may be indiscriminate to how their electricity is produced, being able to achieve financial savings due to reduced consumption could be a more palatable approach for the highly commercialised sectors. Studies have found that generally there is a cost benefit when looking at the lifecycle impacts of energy efficiency focused technologies for new buildings (Clinch and Healy, 2001; Chan and Yeung, 2005; Liu et al., 2014) and retrofit (Mahlia et al., 2005; Liu et al, 2018).

Hong Kong faces many challenges on its road to decarbonising electricity. Although there has been criticism for a lack of engagement on renewables, the limited land availability poses real barriers to utilising these technologies at large scale, and as such there is a reliance on imported energy to make up large portions of non-fossil fuel sources. However, the mostly nuclear based import has an uncertain future too, so whilst the city moves away from reliance on coal and shifts to natural gas, further steps are required to secure lower carbon energy sources.

Planning and guidance also focuses on improving the energy efficiencies of buildings. Targets have been set for reductions and efficiency standards for public buildings, with a broader goal of 40% reduction in energy intensity for the city as a whole. However the use of energy intensity can be misleading, affording growing energy consumption, as long as GDP continues to rise. Furthermore, the lack of stricter targets in the private sector could prove to be another barrier. Whilst energy efficiencies in buildings have generally improved in the city over the past decades, it’s unclear how much this contributes to broader goals. The government seems cautious of overregulating the dominant commercial sector, instead opting for a cautious approach to encourage more efficient buildings through public support and incremental improvements in energy standards, thus preserving the economic growth in a city that has seen accelerated commercialisation. Whilst the plans in place should help reduce future GHG emissions, it is unclear whether they will be enough to help limit global temperature increase.