Environment

Clean Energy

Clean energy refers to providing humans with power sources that create significantly less environmental damage than traditional forms. It encompasses producing and utilising energy, as well as its storage and system integration.

The work brings together researchers from the Faculty of Science with expertise in nanomaterials, crystallography, and catalysts, and from the Faculty of Engineering who are strong in technological applications, design and performance optimisation, information and communication technology, modelling and analysis, methodological development, and system integration.

Production

Wind and solar are two key clean energy sources that offer promising solutions to the energy crisis and air pollution and climate change problems. "Technology advances in wind energy in the last decade have made it economically competitive," said Professor D.Y.C. Leung of the Department of Mechanical Engineering, "and our focus is on wind turbines that can be deployed in a mega-city urban environment where conventional turbines are not suitable because of the wind speed requirement and their environmental impacts."

"Conventional single crystal silicon solar cells, on the other hand, still suffer from high costs, while alternative low cost technologies such as organic devices have low efficiency," said Dr A.B. Djurišić of the Department of Physics. "The focus of this group is therefore on using novel materials (organic, inorganic, or hybrid) to optimise device design and to improve the efficiency of low cost solar cells." Both modelling and experimental studies will help optimise the design of highly efficient, low-cost cells.

"Biofuels are another hot subject area of research in our University," said Professor Leung. "Our team has developed strength in biofuel production and utilisation research aiming to reduce our reliance on petroleum fuels and improve our environment." Biodiesel and biogas are two examples of biofuels currently under intensive study.

Storage

The major drawback of renewable energy sources such as wind and solar is their intermittent generation and reliability. For smooth integration into the grid, energy generated needs to be stored in physical or chemical form. One approach is to use high peak electricity to generate hydrogen, which can be stored for later use. "The high energy density of molecular hydrogen means it can generate a large amount of energy per unit mass compared with other fuel forms," said Professor W.T. Wong of the Department of Chemistry. The researchers will investigate using a porous metal-organic framework as a potential hydrogen storage material.

"If hydrogen can be conveniently generated or stored, then an effective way to utilise it is by means of fuel cells for electrical and vehicular power", said Professor G.K.Y. Chan of the Chemistry Department. Another approach is to store electrical energy in batteries or electro capacitors, which could be used, for example, to power hybrid electrical cars as a greener alternative to fossil fuels. However, numerous problems need to be solved before these can be used for massive storage of electrical energy.

Utilisation

Utilising clean energy will concentrate on two aspects: energy-efficient buildings and solid-state lighting. "Heating, ventilation, and air-conditioning of buildings contributes more than 70% of the building energy consumption in Hong Kong and around 45–50% in China," said Professor Y. Li of the Department of Mechanical Engineering. "Significant gains in energy conservation can be achieved in urban buildings." The focus here will be on integrating mixed-mode technologies to reduce energy consumption and take advantage of the climate as much as possible.

Solid-state lighting is expected to become the mainstream source of illumination within the next ten years, replacing fluorescent lamps and incandescent bulbs. "Light-emitting diode (LED) technology, a form of solid-state lighting, is superior in terms of energy efficiency, reliability, robustness, and environmental friendliness," said Dr A.H.W. Choi of the Department of Electrical and Electronic Engineering. The team aims to produce LEDs that improve energy conversion efficiencies and optimise reliability.

Integration

Reducing or removing technical and non-technical barriers associated with integrating clean energy in the complete energy supply, conversion, and delivery cycle can help promote an aggressive programme for wide adaptation, faster deployment, and higher penetration of clean energy in society.

Integrating clean energy into the overall energy supply can be either grid-connected or off-grid. This research will address both integration problems at the planning stage and the operation stage for both conditions. "Technical problems of integrating clean energy are more challenging in the grid-connected systems," said Dr J. Zhong of the Department of Electrical and Electronic Engineering. "The objective of our research in terms of operation is therefore to design a monitoring and control system using advanced information and communication technology."

"A major non-technical issue is government policy," said Professor F.F. Wu of the Department of Electrical and Electronic Engineering. "We will aim to develop analytical tools capable of assessing the effectiveness of policy alternatives at the planning stage."

Convenor(s) and Key Members