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Title: Investigation on potential, performance and policy of feasible solar PV technologies in buildings in Hong Kong
Authors: Song, Aotian
Degree: Ph.D.
Issue Date: 2018
Abstract: Hong Kong, as a high-density city whose area reaches 1105 km² with more than 7.3 million residents, located in the southeast of China, started to play a significant role in global economic development since last century. The high prosperity and large population no doubt result in huge energy consumption. However, in fact, there is no domestic energy reserves or fossil energy resources in Hong Kong. As a high energy density city and a net energy importer, Hong Kong experiences the dramatic rise in energy consumption and the constantly increasing energy demand poses challenges to the city sustainable development. In addition to the huge energy demand, environmental problems caused by consumption of fossil fuels have also caused widespread concerns, such as the emission of carbon dioxide and the intensification of the greenhouse effect. From the perspective of economy, energy and environment, one of the possible approaches to deal with the energy challenge is to promote efficient use of energy in buildings. Among various types of building energy consumption systems, space air conditioning and artificial lighting contribute to the considerable proportions. The rapid growth of energy demand and the severe environmental pollution problems becomes one of the local bottlenecks. Therefore, besides promoting energy efficient technologies, another way to alleviate the power supply strain and ameliorate pollutant emission is to utilize renewable energy as alternative in Hong Kong, due to its relatively abundant renewable energy resources, especially solar energy. The local annual solar radiation level of 1290 kWh/m2 is abundant for solar photovoltaics (PV) application compared with other countries, including Germany, the United Kingdom, and Japan. Therefore, Hong Kong government has been taking measures to ease the use of electricity pressure and reduce the discharge of the emissions by optimizing the fuel mix for power generation, such as reducing the reliance on fossil fuels, eliminating existing coal-fired generation units, and raising the utility of non-fossil, low-carbon and cleaner fuels, including RE (renewable energy) and nuclear energy. However, in spite of support measures introduced a decade ago, renewable energy still takes up less than 0.1% of overall installed power capacity in Hong Kong at present, much less than the average figure of 30% in Asia. To boost further local development of renewable energy under the new Scheme of Control Agreements, the government signed a new Scheme of Control Agreement with the two power companies to enter into force in 2018, introducing a plan for on-grid tariff so that the private sector may invest in installing and connecting renewable energy power generation equipment to the public power grid, while the power companies would purchase the electricity generated from these devices at a price higher than the normal tariff to encourage the development of distributed renewable energy. The two local power companies will be required to purchase electricity generated from renewable sources from residential/business users at a premium feed-in tariff ("FiT") for connection to public grid, in line with the practice seen in 110 places across the world. Also, according to our previous researches, it proves that building-integrated solar technologies will become the most feasible sustainable energy forms in Hong Kong. That's why this thesis focuses on solar energy development in Hong Kong, especially the application of solar energy technology in buildings. Based on a comprehensive literature review, this thesis aims to find out the research gaps of solar system applications in buildings and to carry out researches in order to provide valuable reference accordingly. In short, we pay much attention on the issues about three 'P's of solar energy development in buildings in Hong Kong, i.e. 'Potential', 'Performance' and 'Policy'. The first main objective of this thesis is to evaluate the application potential of solar energy systems in buildings in Hong Kong. Application potential, obviously, is the most significant factor to identify its possibility of promotion. Then, the application potential of solar systems is divided into four aspects, including market share, energy generation, environmental benefits and cost performance. In particular, after comparing the market in Hong Kong with these in other leading countries, the energy generation of building-integrated photovoltaics (BIPV) was calculated together with its sustainability and environmental benefits. In addition, the Levelised Costs of Energy (LCOE) for BIPV systems were investigated by employing System Advisor Model (SAM). The results present that the calculated Epotential (the annual potential energy output of rooftop PV systems in Hong Kong) is about 5981GWh per year which is equal to 14.2% of total electricity use in Hong Kong in 2011, which means the application of BIPV systems can be a practicable renewable energy method in Hong Kong if beneficial policy supports are further provided. The results also show that, BIPV for rooftops, flexible surface thin-film BIPV rooftops and solar PV shading system, are feasible for commercial buildings in Hong Kong. Their LOCEs are about 20% lower than the local electric price. Other types of BIPV systems, such as solar PV facade and semi-transparent PV windows, can be accepted considering the available combined area and the saved building envelop materials.
Previously, there are some researches focusing on one specific performance rather than the overall performance of solar PV systems. Thus, this thesis also aims to evaluate the overall performance of various solar PV systems, including rooftop BIPV systems, shading-type solar PV claddings and a-Si based PV double-skin systems. On one hand, this thesis focused on the power generation and EPBT, GPBT, CO2 emission rate of different BIPV systems based on Hong Kong domestic geological and climate conditions. On the other hand, the annual overall energy performance (including the power, thermal as well as day lighting performances) of an amorphous silicon (a-Si) based PV window and shading-type PV cladding systems in Hong Kong were also simulated by employing the software of EnergyPlus. For four vertical installation orientations, i.e. facing North, East, West and South, the power generation per unit area all over a year is 317 kWh, 496 kWh, 555 kWh and 504 kWh respectively. For shading-type solar PV claddings, the best orientation and tilt angles for shading-type PV cladding installation in Hong Kong is south facing with tilt angles of 20°. We also found that if the shading PV claddings are connected with an adjustable lighting control system, the energy consumption of artificial lighting could be further reduced significantly. Then, based on the histories of solar PV system development and application in leading countries, this thesis aims to draw up a series of subsidy policies and incentives to help the local PV industry survive through the early pioneering stage. In this part, an input/output methodology is employed. The histories of solar PV development and application were reviewed as the inputs. Five leading economies in solar PV application, i.e. Japan, Germany, Italy, the USA, and Mainland China, were selected and their subsidies and policies from different eras were collected and analyzed. Then, a policy tools box was generated as the methodology output. Their experiences were referred to while a series of strategies and policies that fit Hong Kong's situation was developed. The conclusions of this thesis could be a practical reference for local researchers as well as policy-makers regarding solar energy application, especially BIPV. The major findings are listed as follows: (1) the BIPV system, which requires little extra installation and land, is a promising way of relieving the increasing financial and environmental costs of fossil fuel energy generation; (2) due to the relatively high initial investment and service costs, it is still difficult for solar PV technology to compete against fossil fuels in Hong Kong's local energy market. The government should release subsidies and sustain policies to help the solar PV industry grow; (3) the service and labor market should be opened up to providers abroad to reduce the installation costs of BIPV systems. Measures must be taken to further improve the efficiency of practitioners so that the soft costs could also be cut; and (4) subsidy of solar PV development with PV electricity grants should be implemented to support the PV business, which is in line with the current feed-in tariff. Besides, by employing the TRNSYS building energy model, the life-cycle total cost of traditional vapour-compression cooling system, solar electrical cooling system and solar thermal cooling system are also examined and evaluated. The results show that the solar electrical cooling system is available and economical to be applied to supply the cooling for buildings. On the contrary, the solar thermal cooling system is not suitable for providing the cooling. The total cost of solar electrical cooling system could be reduced by 12.3% when compared with the traditional vapour-compression cooling system. The findings presented in this dissertation can provide a reference for solar energy development and structural adjustment of Hong Kong in the future, and provides a theoretical basis for local energy policy makers to formulate a reasonable energy policy, and the development goal of subsidies in Hong Kong and solar photovoltaic technology.
Subjects: Hong Kong Polytechnic University -- Dissertations
Building-integrated photovoltaic systems -- China -- Hong Kong
Buildings -- Energy conservation
Pages: xxx, 164 pages : color illustrations
Appears in Collections:Thesis

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