Phil Busey Agronomy
Consulting Inc.


 

Biofuels

Sugarcane harvest

Sugarcane harvest, Palm Beach County

Florida's warm climate produces high yields of plant biomass from which biofuel can be processed. Florida-grown biofuel is a promising step towards economic sustainability and away from dependence on foreign oil. Sugarcane, sweet sorghum, and other biomass crops such as switchgrass, Miscanthus, and Arundo donax are biofuel crops that grow well in Florida. Agronomic development of biofuel crops is important for Florida.

Biofuels provide 29% of energy consumption in Brazil, and their development, along with limited petroleum resources, made Brazil the world's first sustainable biofuels economy. Largely as a result of its 37-year biofuel effort, Brazil is independent of foreign oil. Brazil's success is attributed to suitable climate and extensive arable soils, and technological advances in agronomy. With persistent effort, Florida could become successful in biofuels.

Agronomy challenges of profitable biofuel production in Florida are:

Brazil

Mariordo: Panoramic view of the Costa Pinto production plant set up to produce both sugar and ethanol fuel and other types of alcohol. Piracicaba, Sao Paulo, Brazil.

The foregoing are preconditions to a profitable energy crop operation, therefore these factors must be established before choosing a site, processing facility, and management plan for Florida biofuel production.

Processing method is important because processing plants may cost over $100 million, must be designed to handle the kinds of biomass produced, and must have an assured supply of the right kind of biomass feedstock. Liquid biofuels used in transportation, such as ethanol and biodiesel, are processed from crop plant biomass in several ways. High sugar or high starch crops such as sugarcane and sweet sorghum are directly fermented and distilled to ethanol. Lignocellulose from other biomass plants is first preprocessed by acid hydrolysis, gasification, or other methods, prior to formation of ethanol. Lignocellulosic methods are more expensive but can be used on more kinds of biomass, including fibrous grasses and wood chips. Oil and fat-based biomass can also be processed, by esterification to produce biodiesel. All biofuels can be mixed with gasoline or used directly in appropriately adapted engines.

Without tax incentives, biofuel can only compete economically with fossil fuel if it has a FER (Fossil Energy Replacement Ratio) much greater than 1.0. US biofuel is currently mainly Midwestern corn ethanol. Studies have shown that Midwestern corn ethanol is produced at an FER of about 1.4, that is, for every 1.0 joule of energy consumed, 1.4 are produced, a net gain of only 40%. Absent tax incentives, this margin appears to be unsustainable, as it does not sufficiently reward for investment risks and variability of fuel prices. There are several advantages of alternatives to Midwestern corn, including the prospect of lower biomass production costs.

Sugarcane ethanol production in Brazil has a FER between 8 and 10, due to favorable growing conditions and improved agronomic practices. Lignocellulosic ethanol also has a more positive FER than corn ethanol and can utilize diverse biomass sources. A federal study concluded that the FER of soybean diesel is 4.56 (Pradhan, A. 2009. Energy life-cycle assessment of soybean biodiesel). For these reasons, Florida biofuel must take the Brazilian model to improve agronomic techniques. This should increase yield and processing efficiency, while reducing production costs, to bring FER to a high number.

As a start, Florida sugar yields are reported 1.6 to 6.9 tons per acre for sweet sorghum (Vermerris, W., et al., 2011. Production of biofuel crops in Florida: Sweet sorghum). Sugarcane yields are high in Florida organic soils. In Florida the main opportunity for expansion of sugarcane is in sand land, which will be more demanding of nutrient requirements. It is essential to keep fertilizer and other crop production costs to a sufficiently low amount to allow for profitability.

Agronomy assessment may reduce biofuel production risks, but there is also considerable uncertainty in the profitability of biofuel in Florida, including capital financing for production facilities, and price competition with other fuel sources, petrochemical as well as corn ethanol, and the future of the Renewable Fuel Standard Program. The VEETC (Volumetric Ethanol Excise Tax Credit), an incentive of $0.45 per gallon, expired for corn ethanol in 2011. Depending on the crop and production method, break-even occurs at ethanol prices somewhere above $2.00 per gallon. Depending on how the EPA treats products other than corn ethanol, this could be an advantage or disadvantage for Florida.