Along with development of technology and economy, as well as advancing standard of human life, science has brought great convenience for mankind. However, economic growth has induced the progressive depletion of energy (coal, petrol and electricity) and the environment has suffered severe damage (CO2, greenhouse effect and ozone layer…). If the present status continues, mankind will return to aboriginal life eventually. Since energy experts worldwide have forecasted that petrol over the world will start to run out after 10 years, a solution or measure of prevention can only be sought by utilizing our wisdom.