Renewable energy resources have the potential to meet the growing energy demand through the use of renewable energy resources such as solar, wind, hydropower, geothermal, etc. Photovoltaic technology is one of the most favoured renewable energy technologies. Photovoltaic (PV) generates electricity using solar cells. The photovoltaic effect allows semiconductors to generate electricity using sunlight through an electronic process. Solar cells are manufactured either from crystalline silicon photovoltaic cells or thin- film photovoltaic cells.
Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon),elemental molecules made from one type of atom (e.g. oxygen), or compound molecules made from a variety of atoms (e.g. carbon dioxide). A gas mixture would contain a variety of pure gases much like the air. What distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colorless gas invisible to the human observer. The interaction of gas particles in the presence of electric and gravitational fields are considered negligible as indicated by the constant velocity vectors in the image. One type of commonly known gas is steam.