Biofuel and Advanced Biofuel

Abstract

A. Ethanol From Cellulose Cellulosic ethanol is the most promising second-generation biofuel, but the cost of production limits its viability, though costs are declining. (203) In order to qualify for a renewable identification number for cellulosic ethanol, production must meet requirements include lifecycle greenhouse gas emissions, as determined by the Administrator, that are at least 60 percent less than the baseline lifecycle greenhouse gas (GHG) emissions from gasoline or diesel, whichever the fuel is replacing. (204) In June 2012, the first tradable renewable identification number was issued to Blue Sugars for cellulosic ethanol production, but the company went bankrupt in 2013. (205) The CAA requires 0.1 billion gallons of cellulosic biofuel to be used in the year 2010 and its use to increase in steps to 16.0 billion gallons in 2022. (206) The administrator of EPA is given limited power in CAA section 211(o)(4) to modify the advanced biofuel and cellulosic requirements concerning the mandated percentages of GHG reductions. Section 211(o)(7)(A) allows the Administrator to modify the utilization requirements to prevent harm to the economy, the environment, or because of inadequate production. (207) This power has been used to adjust production requirements; in 2012, the industry produced only 20,069 gallons of fuel. (208) An alternative approach proposed by EPA to deal with the industry's performance is to change the definition of cellulosic ethanol to allow more fuels to qualify as cellulosic biofuels. (209) Technical amendments to the RFS to clarify the number of cellulosic biofuel identification numbers for fuels of varying cellulosic content were promulgated on July 8, 2014. (210) Ethanol produced from cellulose or other non-food inputs is a promising source of biofuels. It can be produced from trees and forest residues, although there is no commercial production of fuel from woody biomass except for the use of pulp and saw mill wastes to produce heat, steam, and electricity. (211) Fast growing woody crops such as hybrid willow and poplar have the potential to be feedstock for cellulosic fuel. (212) Another potential feedstock is perennial grass, such as switchgrass or Giant Miscanthus. Switchgrass is a perennial Midwest and Southeast grass with nearly three times the yield of hay. Giant Miscanthus is a native of Asia has some use as a fuel in Europe. The advantage of perennial grasses is they are not normally irrigated and therefore require less water, fertilizer, and pesticides than most crops, and their extensive root system reduces soil erosion and provides habitat for wildlife. (213) Some of the plants approved for renewable fuel production by EPA, such as giant reed and napier grass, are invasive species other government agencies are trying to control. (214) Agricultural residues not specifically grown for food such as corn stover can be used to produce cellulosic ethanol, although the use of corn stover for fuel could lead to increases in soil erosion. (215) A 2007 lifecycle study found the energy requirements for cellulosic fuel production are low for switchgrass and hybrid poplar feedstock when compared to corn crops. Other experts claim cellulosic ethanol has a 100 percent energy gain, compared to the 34 percent energy gain for corn. (216) Utilizing non-food inputs is important because if all of the United States corn harvest is devoted to ethanol production it would offset about 25 percent of national gasoline demand. (217) An advantage of using cellulosic feedstock is it can be grown on marginal or degraded land can provide increased regional agricultural income without utilizing land used for food production. (218) Moreover, cellulosic feedstocks require less pesticides and fertilizer than corn-based ethanol. (219) However, demand for cellulosic ethanol could result in adverse impacts on forests if they were cut to produce fuel or converted to plantations of fast growing trees. …