CARIBBEAN BASIN ETHANOL DEHYDRATION
ENERGY USUAGE AND CO2 EMI SSI ONS
Hy drous ethanol is imported from Brazil to dehy dration plants in the Caribbean Basin w h ere it is processed through m olecular sieve technology into anhy drous ethanol . The dehy dration process requires steam energy to heat and cool ethanol. The energy used to create steam is generated by burning fossil fuels which range from natural gas in Trinidad to heav y fuel oil at t he plants in the other countries. Industry experts have calculated that approximately 4000 BTU’s of fuel and .05kwh of electricit y are used in the conversion of one gallon of hy drous to anhy drous ethanol

. 1 All this fossil fuel ene rgy

usage represents les s than 5 gCO2MJ when calculated using the GREET model. Additional CO2 emissions are generated from the transportation of the ethanol from Brazil to the Caribbean Basin and then onward to the United States. These emissions are no greater than from the tr ansportation of ethanol directly from Brazil to the United States. Also, pathway s for Brazilian cane

- based ethanol through CB ethanol deh ydration facilities are more economically viable than the pathway

for ethanol shipped via a direct route for anh yd ro us ethanol from Brazil to California . As noted b y EPA in t heir proposed RFS2 rules, “the most likely route(for Brazilian cane

- based ethanol is) through the Caribbean Basin Initiative”” because the ethanol would not be subject to the 54 cent per gallon and 2.5% ad valorem tariffs. Indeed, since a dut y drawback loophole ended in September 2008, direct Brazil to U.S. ethanol shipments have practicall y ceased.
In anal yz ing the differences in the direct Brazil to U.S. pathway and the CB deh ydration pathway to determine the lifecy cle emissions, it is necessary for a fair comparison to look at such factors as the fugitive emissions from the pipelines carry ing the hy drous or anhy drous ethanol as well the natural gas. Dehy dration plants in the Caribbean Basin are at or near the ports so the distances traveled

- and the accompan yi ng fugitive emi ssions

- in pipelines are negligible. This is not the case in Brazil. Fossil fuels such as natural gas may be shipped hundreds of miles and even imported from Bolivia in pi pelines of various age and states of repair

. Since the same technology is used in Brazil and in CB countries to deh ydrate ethanol, the same amount of energy

should be generally

required to power the dehy dration process in Brazil and the Caribbean Basin

. The dehy dration plants in the Caribbean Basin are 1. Source: Swain, R.L . Bibb, “Molecular Sieve Dehdy rators. How they

became the industry standard and how they

work”, Chapter 19 in the Alcohol Textbook, p. 292newer than those in Brazil and bec ause of age and technology are more efficient. These factors as well as the greater emissions from the cy clohexane and benzene used in the azeotropic distillation of some of the deh ydration plants in Brazil needs to be considered in comparing the deh ydration pa thway s in the Caribbean Basin and Brazil.
We encou rage EPA to use these factors as credits and lower the life cy cle carbon footprint of Caribbean Basin dehy dration. The energy

usage differs from plant to plant in the Caribbean Basin. The table below i ndicates the range.

CO2 EMISSI ONS FROM CB ETHANOL DEHYDRATION
ENERGY USAGE Per Gallon of Anhydrous Produced
Gallons of fuel oil .031 to .044 BTU of natural gas 5,000 KWH of electricity .0458 to .0617

CO2 EMI SSI ONS CALCUL AT IONS
Natural Gas Fuel Oil Electricity CO2 emissions per gallon of anhydrous ethanol produced (lbs) 0.47 0.65 CO2 emissions (gCO2/MJ) 2.64 3.67
CO 2 emissions (gCO2/MJ) per gallon of anhydrous ethanol produced 1.31
TOTAL CO 2 EMISSIONS FROM ENERGY USAGE 3.95 4.98
Caribbean Basin ethanol dehydration emits less than 5 g of CO2/MJ from fossil fuels used to produce anhydrous ethanol. Credits from factors i ndicated above should be applied to reduce this number. Nevertheless, this number should be within the life cycle threshold to classify CB ethanol as an advanced biofuel.