Silicon, an important semiconducting material and alloying element in metallurgy and chemistry, is one the most abundant elements in the earth as oxides and silicates. However, the rapid growth of the solar cell demand is making a shortage of solar-grade silicon feedstock. Expensive high-purity scrap silicon (99.9999999% Si) is mainly used as the raw material to produce solar-grade silicon (SOG-Si) (99.9999% Si). Many researchers reported that relatively inexpensive metallurgical grade silicon (98-99% Si) can be the alternative raw material. Various techniques have been developed to produce solar grade silicon. Among them, Siemens process is the current dominating energy-intensive solar grade silicon production method that emits chlorine. At present, Hemlock (USA) is dominating the world by producing photovoltaic (PV) polycrystalline silicon. In Australia, There is no available commercial production for solar grade silicon production, but the abundance of raw materials such as quartz, combined with the expected growth in photovoltaic silicon demand, has fuelled research in this area. This paper evaluates the progress of SOG-Si production in the world, identifies problems and technical challenges associated with current and alternative techniques.