Energy has been playing a crucial role in the global economy after the Industrial Revolution. Among all primary sources of energy, fossil fuels have dominated the world’s energy market since the 19th century. According to a statistical report released in 2004 by the UN, the proven global oil reserves were 1,147 billion barrels, which is only available for another 41 years at current consumption rates, while natural gas may be depleted in 67 years.

Basically the wide-scale use of fossil fuels enabled the Industrial Revolution. However, from the environmental perspective, the carbon dioxide emissions from the combustion of fossil fuels are probably the main cause of global warming. The excessive amount of carbon dioxide may trigger significant climate changes, which endanger the Earth’s ecological system. In view of the severity of the problem, most of the countries in the world signed and ratified the Kyoto Protocol, which entered into force in 2005. Under the Protocol, 37 industrialized countries commit themselves to a reduction of four greenhouse gases (carbon dioxide, methane, nitrous oxide, sulphur hexafluoride) and two groups of gases (hydrofluorocarbons and perfluorocarbons) produced by them. The target agreed upon was an average reduction of 5.2% from 1990 levels by the year 2012.

In addition to reducing fossil fuel use, another better, more ideal solution is the development of clean, alternative energy sources that do not generate carbon dioxide emissions. Many types of renewable energy, including solar, wind, hydro, biomass and geothermal energy, etc., have been considered good options. And along with the advancement of technologies, the applications of renewable energy resources are increasingly cost-effective and feasible with greatly improved energy conversion efficiency. Better yet, the common features of all these renewable energy sources are clean and eco-friendly.

It is expected that fossil fuel use will be reduced by 50% by 2050, meaning that renewable energy will become a much larger source of energy than it does now. Among all renewable energy sources, solar energy is the most promising one, because the amount of solar energy reaching the surface of Earth is so vast that in one year it is about twice as much as will ever be obtained from all of the Earth's non-renewable resources of coal, oil, natural gas, and mined uranium combined. And the photovoltaic technology is commonly regarded as the most commercially viable means to harness solar energy.

Installations of solar PV systems have been strongly promoted in many countries around the globe. European countries are currently the major markets for PV systems, followed by USA and Asian countries such as Australia, China, Japan, Korea, Taiwan and Thailand. With growing global concern over climate change and the accompanying rush to find alternative sources of energy, the long-term outlook for the solar photovoltaic industry is bright, and the increasing demand will continuously expedite the growth of the industry.