Glycerol is a by-product of biodiesel, soap and fatty acid manufacturing plants, which are now facing sustain ability threats and a reduction in prices in the market due to its oversupply as a result of the rapid expansion of biodiesel plants all over the world. The global production and consumption of glycerol, as well as demand and supply, are evaluated here. Glycerol offers a wide range of new opportunities based on its transformation in many applications due to its unique properties, renewability and availability in the current market. This paper is a comprehensive review of the utilization of glycerol as a value-added commodity, including in the synthesis of chemicals, in the production of hydrogen gas, as a fuel additive, as a fermentation substrate, in the co-pyrolysis and co-gasification of glycerol, in methanol production, in the development of fuel cells, in wastewater treatment and in many other applications. In the future, glycerol definitely will become a promising renewable feedstock in biorefineries to synthesize fuel, chemicals and power. (C) 2016 Elsevier B.V. All rights reserved.