Glycerin, also known commercially as glycerol, is a byproduct of the transesterifcation process for producing biodiesel fuel. This is a fortunate fact due to the increasing demand for biodiesel fuel worldwide and the widespread uses for glycerin in industry. Established uses for it include in many cosmetics and foods, and in a variety of soaps. It is also being evaluated as a useful ingredient in animal feed.
As the biodiesel fuel market skyrockets, glycerin waste from its production has saturated the marketplace. In the United States, biodiesel production was around 75,000,000 gallons per year (284,000,000 liters) in 2004. As of 2008, that volume had increased to 650,000,000 gallons per year (2,461,000,000 liters). With every metric ton of biodiesel produced, 220 pounds (100 kilograms) of glycerin byproduct is also produced. Estimates put current glycerin production as a waste product of biodiesel alone at around 1,224,000 metric tons, with a global demand slightly below that of 900,000 metric tons.
Though this is a boon to industries that purchase it for their products, using glycerin from alternative fuels is not the best of choices. It is typically about 80% pure when acquired as a byproduct of biodiesel production, whereas intentionally refined glycerin is 99.5% pure. Due to its level of impurity and the excess of supply on the world market, the value has dropped nearly to zero, and some biodiesel producers have to pay to have it taken away as waste and incinerated.
When supply and demand balances out, prices will rise, as glycerin has such a diverse range of uses. It is commonly used as an artificial sweetener in low-fat foods and as a thickening agent. It can be made into industrial foam and substituted for polypropylene plastic, which is derived from petroleum. Glycerin is a core ingredient in many industrial chemicals, including explosives, hydraulic fluids, and coolants. It is also one of the key plasticizers in industry, a material that gives plastics better flexibility, softness, or viscosity.
Aside from those common uses, one of the biggest markets for many years has been in cosmetics, pharmaceuticals, and health and beauty products. Glycerin is routinely added to cough syrup, lotions, toothpaste, and more. Running athletes sometimes take glycerin as a method of staying hydrated in hot temperatures. Studies have shown that it can increase endurance at levels of between 22%-32%, and Olympic athletes have also used it for this reason. Stomach remedies for children are often made from liquid glycerin capsules as well.
While production levels increase, many researchers and companies are looking for further uses for the substance. Two big areas being investigated are as a 5% additive to chicken and other livestock feed, and as a suitable substitute for the propylene glycol market. Propylene glycol (PG) is currently used in pet food, paints, cosmetics, and many other compounds, and the market for PG is around 1,000,000 tons (907,184,740 kilograms) per year and growing. As glycerin is developed for these uses, it is finding its way into everything from fortified milk to ethanol and antifreeze.