Do biorefineries require a lot of water to produce ethanol?
Yes, biorefineries do require substantial amounts of water to produce ethanol. To make a gallon of gasoline, the process requires 1.5 gallons of water. Corn grain ethanol requires 4 gallons of water per gallon of fuel and cellulosic ethanol requires about 9 gallons of water per gallon of fuel. Cellulosic ethanol production is expected to be refined as it reaches commercial scale and require a similar amount of water as corn grain ethanol production. Some commercial scale (50 million gallons per year and up) facilities have designed a closed system where waste water is treated on site and sent back into the production process, thus significantly reducing the demand for fresh water.
