First we see what is sustainable Energy? Sustainable energy is the energy which fulfill our energy demand without affecting the environment. All renewable energy like wind, solar, hydro power, geo thermal are sustainable energy source. Is Gas is Sustainable Energy? No, Gas is not sustainable Energy. Which creates harm if its leak, that are not sustainable energy. Consider two gaseous LPG and LNG Liquefied Petroleum and Liquefied Natural Gas The main difference is that Liquefied Petroleum Gas , LPG , is stored under high pressure, while Liquefied Natural Gas , LNG , is not under pressure. ... Propane is processed into gas and lpg is liquefied and that is because it is used as motor fuel. Need LPG Bulk supplier - Just visit samagas.com