SAF is a liquid fuel currently used in commercial aviation which reduces CO2 emissions by up to 80%. It can be produced from a number of sources (feedstock) including waste oil and fats, green and municipal waste and non-food crops. An estimated 1 billion dry tons of biomass can be collected sustainably each year in the United States, enough to produce 50–60 billion gallons of low-carbon biofuels. These resources include: Corn grain Oil seeds Algae Other fats, oils, and greases Agricultural residues Forestry residues Wood mill waste Municipal solid waste streams Wet wastes (manures, wastewater treatment sludge) Dedicated energy crops.