People use various energy sources to meet the life needs and to develop the prosperous civilization. However, the Earth's environment is degrading daily in many aspects, such as the greenhouse effect, ozone depletion, CO2 emission, nuclear power plant pollution, acid rain, rainforest depletion, and so on. All these issues have been closely related to our consumption of energy.
When the shortage of electricity, coal, oil, and water has become the inevitable reality, our ways of living are facing more difficulties accordingly. We should stop exhausting our natural resources and start to change our method - from "excavating energy" to "green energy". As a result, it has become the most urgent task for us to utilize "green" and "efficient" methods that can conserve our energy and natural resources without any pollution or damage to the environment.