Biofuels as Alternatives to Diesel and Gasoline Bob McCormick November 27, 2007 NCSL Advisory Council on Energy Phoenix Vehicle Technologies Program Fuels Technologies Subprogram Kevin Stork, Technology Manager
What are biofuels? Those available today: Biodiesel Ethanol Those available in future: Butanol and mixed alcohols Hydroprocessed fats and oils (renewable diesel) Non-ester renewable diesel (NERD) May be available in 2008 or 2009 Hydrocracked fats and oils (renewable gasoline) Refined pyrolysis liquids Biomass gasification to liquids
Biofuels are not THE answer GHG Emission Reduction Driving Less: mass transit, car pooling, telecommuting, -Biobutanol -HDRD
BIODIESEL
What is biodiesel? Mono-alkyl esters of fatty acids (i.e. methyl or ethyl esters) 100 lb triglyceride + 10 lb alcohol = 10 lb glycerine (byproduct) + 100 lb mono-alkyl ester soy oil methanol Biodiesel High cetane (avg. over 50) Ultra low sulfur (avg ~ 2 ppm) Used as a blend with petroleum diesel (20% or lower) Blends have energy content per gallon similar to diesel Poorer low temperature properties with high blends Blends can be used with no engine modification Most OEMs approve up to B5, Cummins B20
Biodiesel Potential and Production 1.7 billion annual gallon resource 3.6 billion annual gallons by 2016 Plus potential for importation of some feedstock (palm oil) Same feedstock resource for biodiesel and NERD US on-road market: 40 billion annual gallons 300000000 250000000 U.S. Biodiesel Production NREL/TP-510-34796, June 2004 U.S. Biodiesel Feedstock Supply Other New Animal Fats Greases Existing Feedstock Supplies: 1.7 billion annual gallon Animal Fats New Vegetable Oils Other Vegetable Oils Soy Normal growth in animal fat production Increased soy oil yield Recovery of corn oil from ethanol production Conversion of wheat acreage to canola Other oil seed crops Potential New Feedstock Supplies: 1.9 billion annual gallons Gallon/Year 200000000 150000000 100000000 50000000 0 1999 2000 2001 2002 2003 2004 2005 2006 Current production capacity is more than 1.4 billion annual gallons (Aug. 2007) Nearly 1.9 billion annual gallon additional capacity under construction or planned (Source: NBB)
Biodiesel Market Penetration Issues Fuel Quality and Quality Standards ASTM Specification for Blends Test Methods Fuel Stability Low-Temperature Operability Air Quality Impact NO x Emissions Toxic Compound Emissions Testing with Advanced Emission Controls DPF and NO x Control Catalysts Engine/Emission Control Systems Durability Materials and Component Compatibility Dynamometer/Bench Durability Tests In-Use Fleet Evaluation
Emission Impact of B20 10% to 25% reduction in PM and CO 5% to 20% reduction in toxic compounds (aldehydes, PAH, NPAH) Chart from EPA420-P-02-001, Draft Report, October 2002 No consensus on NO x impact EPA review of published data found B20 causing NO x to go up ~2% But many studies show NO x going down Effects of Biodiesel Blends on Vehicle Emissions: http://www.nrel.gov/docs/fy07osti/40554.pdf NREL assessment of EPA dataset and more recent data suggests no NOx impact for B20 Data not representative of inuse on highway engines
Biodiesel s Effect on NO x Emissions EPA Review - Engine Data Percent change in NO x for B20 ranges from -7% to +7% Average change in NO x +2% (EPA s conclusion) 95% Confidence Interval 43 engines included 72% of engines pre-1994 95% pre-1997 Many B20 tests show NO x decreasing: All are for soy biodiesel Engine standards groups D and E EPA420-P-02-001, Draft Report, October 2002
Reexamination of EPA Database Average percent change for each engine tested Multiple data points for certain engines, but totally independent tests All Engines Average NO x =2.0% 4-Stroke Engines Only Average NO x =0.2% 40 40 Percent Change in NO x Emissions 30 20 10 0-10 Percent Change in NO x Emissions 30 20 10 0-10 -20 20-20 20 Percent Biodiesel Percent Biodiesel
Diesel Particle Filters Exhaust flows through porous wall-flow elements PM is trapped on the walls of the filter When exhaust temperature is high enough, PM is burned off Many retrofit systems are passive OE systems are actively regenerated Precious metal is loaded onto filter walls to lower the temperature required for regeneration Issues: Regeneration at low temperatures/duty cycles Plugging with incombustible materials like lube oil ash
B20 Testing with DPF HD FTP Cummins ISB with JM DPF, engine dyno Reduction with DPF ranges from 20% to 70%, depending on basefuel, test cycle, and other factors Reduction in sulfate emissions Increased PM reactivity BPT DPF temp where soot load rate is equal to soot regeneration rate BPT with B20 and B100 is lower than 2007 Cert by 45ºC and 112º C Williams, et al., Effect of Biodiesel Blends on Diesel Particulate Filter Performance SAE 2006-01-3280
ETHANOL
Ethanol and Ethanol Blends Alcohol fuel produced from starch crops or cellulosic biomass such as trees and grasses: Currently, corn is primary feedstock Cellulosic feedstock in development High octane (100+): Limited to a maximum of 10% ethanol in conventional gasoline Used to enhance octane of gasoline (E10) As oxygenate to reduce CO emissions during combustion (E10) Ongoing work looking at some increased level in conventional gasoline (Exx) Used as E85 as an alternative fuel E85 summer blend is approximately 85% ethanol and 15% gasoline (E85). Winter blends may be as low as 70% ethanol Requires flex-fuel vehicle (FFV)
U.S. Biomass Resource Assessment Updated resource assessment - April 2005 Jointly developed by USDOE and USDA Referred to as the Billion Ton Study
The 1.3 Billion Ton Biomass Scenario Billion Barrel of Oil Equivalents Based on ORNL & USDA Resource Assessment Study by Perlach et.al. (April 2005) http://www.eere.energy.gov/biomass/pdfs/final_billionton_vision_report2.pdf
9 8 7 6 5 4 3 2 1 0 Ethanol Production Actual and Projected U.S. Ethanol Production 1999-2012 Billion Gallons per Year Current estimated annual rate of production is 6.78 billion gallons (Aug 2007) Additional 7.5 billion gallons of capacity under construction Source: Ethanol Monitor Nov. 16, 2007 Cellulosic Ethanol 2005 EPACT RFS - Minimum U.S. Ethanol Production Source: December 2005 Ethanol Today Magazine 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Total US gasoline market ~140 billion annual gallons E10 Market Size Limitation 10% blending wall Dramatic expansion of E85 and FFVs Blends above E10 in conventional gasoline (Exx)
E85 and Flex Fuel Vehicles (FFVs) Flex fuel vehicles can use E85, unleaded gasoline or any combination of the two. Currently there are approximately 1200 stations in the U.S. offering E85. Key component differences in a flex fuel vehicle are: Higher volume fuel pump Larger diameter injectors Different materials in the fuel system, heads, valves, and piston rings ECU calibration Conventional vehicles are not certified for use with E85 E85 use in a non- flex fuel vehicle causes poor acceleration, increasec in maintenance costs, eventual component failure FFVs are available in light duty vehicles including cars, vans, ½ ton pickups, and SUV s. There are an estimated 5 million FFVs on the road in the U.S.
Performance of E85 E85 has 27%-36% less energy content than gasoline so fuel economy (mpg) is adversely affected. OEM s estimate 15%-30% decrease in mileage. Needs to cost 20%-30% less to make economic sense NREL ongoing review of all air pollutant emission data for E85 (preliminary results): E85 versus Gasoline Tier 1 Tier 2 in non-ffv: NMHC -27% -- NMOG -- -2% CO -18% -42% NO x -54% -37% PM reduced reduced Formaldehyde +56% +13% Acetaldehyde +2000% no data Benzene -86% no data Butadiene -91% no data
Life Cycle Impacts It is critical to evaluate the life-cycle environmental impacts of any new technology Petroleum usage Greenhouse gas emissions Water consumption Land use Air pollution Other factors
Corn Ethanol Net Energy DOE studies find: Corn ethanol FER = 1.2 to 1.6 Cellulosic ethanol FER = 5 to 10 Soy-biodiesel FER about 3
Petroleum Displacement
Greenhouse Gas Impact
Thank You! robert_mccormick@nrel.gov http://www.nrel.gov/vehiclesandfuels/npbf/publications.html GHG Emission Reduction Driving Less: mass transit, car pooling, telecommuting, -Biobutanol -HDRD
Ethanol Ongoing Studies E85 quality survey E85 and Exx cold start and driveability E85 and Exx emissions from Tier 2 vehicles, including toxic compounds Exx performance in small engines (lawn and garden, marine, generators, etc.)
Soy-Oil Biodiesel Energy Balance Biodiesel uses 0.31 MJ of fossil energy to produce 1 MJ of fuel product energy B100 Fossil energy ratio = 3.2 B20 reduces life cycle petroleum consumption by 19% B20 reduces life cycle CO 2 emissions by 16% Petroleum diesel uses 1.2 MJ of fossil energy to produce 1 MJ of fuel product energy Fossil energy ratio = 0.83 Analysis from NREL/TP-580-24772, May 1998
Corn Agriculture Productivity Average corn yield ~20% higher than 1990 Trend of increasing yield since about 1950 Significantly less fertilizer is being applied per bushel