Abstract
Electricity is very convenient and useful energy, because it could be easily converted other types of energy like a light, a heat, or a motive power. However it produces lots of CO_2, which causes the earth to be warmer, when it is generated. Though Electric Power Companies make efforts to decrease CO_2 at generating the electric power, it is required to decrease CO_2 more. In this situation, trying to save energy more in the lighting field, where 16% of the electric power supplying to the residential area is spent, is very important. In this chapter, we will mention the recent regal restriction and the new technology in order to reduce CO_2 regarding the light source and systems.
