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Center for Diesel Research
Next Generation Fuels and Vehicles
David KittelsonCenter for Diesel Research
Department of Mechanical EngineeringUniversity of Minnesota
NextGen Technical Advisory Workshop on Bioenergy
Minnesota Department of CommerceSeptember 12, 2007
Center for Diesel Research
Outline
• Introduction
• Ethanol
• Biodiesel
• DME
• Plug-in Hybrid
Center for Diesel Research
Alternative transportation fuels
• Non petroleum fossil fuels– CNG– LPG– Coal and natural gas based synthetic fuels (Fischer-Tropsch)
• Biofuels– Near term– Long term
• Conservation• Energy carriers
– Electricity (high grade, already work)– Hydrogen (low grade, must be converted to work)
Center for Diesel Research
Alternative transportation fuels
• Biofuels– Near term
• Ethanol (corn, wheat, sugar,..)• Biodiesel FAME (soy, canola, rapeseed, palm,..)• Biogas (plant and animal waste)
– Long term• Biological conversion process
– Ethanol (cellulose, sorghum, cassava,..)– Biodiesel (camelina, algae, jatropha, castor,..)– Butanol (beet sugar, cellulose,..)
• Thermochemical conversion process (cellulosic materials, wood, grasses, etc.)
– Fischer-Tropsch liquids– NExBTL biodiesel (from plant and animal oils)– Dimethyl Ether– Methanol– Mixed alcohols
Center for Diesel Research
Renewable Fuels for Engines
• Gasoline engine fuels– Ethanol
• Works well in standard automotive engines in blends up to 20%, any blend to E85 works in flexible fuel engines
• Potential efficiency gains in dedicated E85 engines• Recent emission concerns• Non fungible
– Butanol• Promoted by BP, Dupont and British Sugar• Similar to gasoline in performance and emissions• Fungible
– Biogas• Requires engine modifications for gaseous fuel• Mainly used in stationary engines but sold in service stations in Sweden• Some power reduction
– Methanol• Toxic and corrosive but excellent racing fuel• Has been considered seriously in the past
Center for Diesel Research
Renewable Fuels for Engines
• Diesel engine fuels– Biodiesel (FAME – fatty acid methyl ester)
• Compatible with most engines in blends up to 20%• Reduced CO, HC, and PM emissions• Oxidative stability• Cold weather issues
– Fischer-Tropsch liquids• Very high grade synthetic diesel fuel• Reduced emissions
– NexBTL• Developed by Neste Oil, Finland• Very similar to Fischer-Tropsch liquids
– Dimethyl Ether (DME)• Promoted by Volvo, Mitsubishi, Nissan• LP gas• Very low emissions• Requires modified engine and fuel system
Center for Diesel Research
Ethanol
• E10 (10% ethanol, 90% gasoline) is well established and works well in modern vehicles
• Minnesota already produces enough ethanol for statewide E20• E20 has been mandated for Minnesota in 2013 but must be demonstrated to be
suitable for current and future vehicles– Programs here and in Mankato examines many E20 issues
• Cold starting, driveability• Engine wear• Corrosion, elastomer deterioration• Emissions
• E85 and any other blend works well in flexible fuel vehicles (FFV)– Gaseous emission similar to gasoline although some studies suggest increased emissions– Lower particle emissions– Slight increase in engine efficiency but 15 to 25% fuel consumption penalty due to lower
energy content of fuel• Energy balance is a concern
– Current corn based ethanol is only 20% renewable, 80% fossil– Cellulosic ethanol much better, roughly 80% renewable, 20% fossil– Cellulosic ethanol could be made from corn stover, prairie grass, etc.
Center for Diesel Research Center for Diesel Research Center for Diesel Research
Soybeans the Main US Biodiesel Feedstock: Soy Methyl Ester (SME) Biodiesel Production
100 lbs. of soybean oil
+
10 lbs. methanol
=
100 lbs. soy biodiesel (B100)
+
10 lbs. of glycerin
Biodiesel may also be made from animal fat, restaurant grease, canola, rapeseed, palm, etc.
Center for Diesel Research
Comparison between biodiesel and petroleum diesel• Little fuel consumption penalty• Considerable engine to engine variation in emissions
– Reduced emissions of HC, CO, and air toxics– NOx emissions vary– Sharply decreased soot emissions but increased volatile particle emissions
• Minnesota law mandates most diesel fuels are B2, but the state currently produces enough biodiesel to replace 8% of diesel fuel
• Most manufacturers don’t recommend use of blends higher than B5 to B20– Solvency– Cold flow– Oxidative stability
• Quality control and filter plugging still issues• Energy balance for soy based biodiesel about 50% renewable, 50% fossil• New feedstocks being considered
– False Flax (Camelina)– Algae– Genetic modifications of seed plants
Center for Diesel Research
DME properties
• Physical properties similar to propane – LP gas• Nontoxic• DME is a gas at ambient conditions and unlike MTBE is
not a groundwater pollution threat• Uses
– Aerosol propellant in the cosmetic industry to replace CFC propellants
– Diesel fuel• High efficiency• Soot free combustion• Fuel system modifications required
– Fuel cell fuel– Propane replacement
• May be produced from natural gas or biomass including wood waste, corn stover, prairie grass
Center for Diesel Research
”Well-to-wheel” analysis (Volvo study)Energy efficiency and Greenhouse gasesCourtesy - Anders Röj, Volvo Technology Corporation, Fuels and Lubricants
Volvo Technology Corporation, Fuels and Lubricants
Future Fuels for Commercial Vehicles
”Well-to-wheel” analysis (Volvo study)Energy efficiency and Greenhouse gases
0%
10%
20%
30%
40%
0
250
500
750
1000
Energy efficiency, %
GHG, g/kWh
g/kWh
Fossil Renewables
These figure include production, transport, and end use. Ethanol figures are based on European practice from wood or wheat
Center for Diesel Research
Improving vehicle efficiency - conservation is effectively a renewable fuel
• Hybrid vehicles (energy storage and second propulsion system)– Electric hybrid
• Battery storage – high energy density, low power density• Electric motor/generator
– Hydraulic hybrid• Hydraulic accumulator storage – low energy density, high power density• Hydraulic motor/pump
– Plug in hybrid• Battery storage to allow electric only range of 10 to 60 miles• Larger electric motor, smaller engine• Batteries are limiting technology• Very large potential reduction in petroleum use
• Hybrids offer largest benefit for around town driving – 25-70%• Diesel engines – 30% fuel saving at same performance level
Center for Diesel Research
Electricity as a transportation energy carrier – the plug in hybrid
• The efficiency of delivery of renewable energy to the wheels is 3 – 4 times higher for electricity than for hydrogen
• The plug in hybrid avoids most of the range and battery problems associated with conventional electric vehicles
• What is a plug in hybrid?– Electric hybrid with larger battery and facility to plug in and charge from
utility power– A plug in with an all electric range of 40 miles could do 80% of all of the
daily trips made by a typical driver on electricity alone– This could lead to reductions in petroleum use of the same order –
about 80%– Many aftermarket conversion kits are available but the only current
prototype from a large company is the Daimler-Chrysler Sprinter van with an electric only range of about 18 miles and fuel savings of up to 50%
– Toyota and GM have both announced plans for plug in hybrids– Batteries are the key limiting technology
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Hybrid systems – some examples
– Parallel electric hybrid – up to 30% fuel saving• Honda Insight, Civic• Allison transit buses
– Series / parallel electric hybrid – up to 30%+ fuel saving• Toyota Prius• Ford Escape
– Series electric hybrid – up to 50% fuel saving• DARPA HMMWV
– Parallel hydraulic hybrid – up to 35% fuel saving• EPA / Eaton / International collaboration developed new UPS (50) .
FedEx (75) delivery vans• Eaton / Peterbilt – refuse trucks
– Series hydraulic hybrid – up to 70% fuel saving• EPA / Eaton UPS delivery van
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Conclusions
• Corn based ethanol and soy based biodiesel are the are the primary renewable fuels used in the US today– Energy balance an issue– Competition between food and fuel– Cellulosic ethanol and biodiesel based on other oil seeds and
algae offer future promise
• DME offers future promise as a second generation biomass to liquid diesel fuel that could be produced from many different feedstocks
• The plug-in hybrid offers potential for dramatic reductions in petroleum use
Center for Diesel Research
Center for Diesel Research
Biodiesel Blends and Emissions
0 50 100
B2
B5
B10
B20
B100
Biodiesel Petroleum diesel
B100B100 = 100% biodiesel
B20B20 = 20% biodiesel + 80% petroleum diesel
B10B10 = 10% biodiesel + 90% petroleum diesel
B5B5 = 5% biodiesel + 95% petroleum diesel
B2B2 = 2% biodiesel + 98% petroleum diesel
Data from USEPA 2002
SME
SME
RME
FAME
Center for Diesel Research
Black liquor to engine fuels - Ideal use of low grade biomassCourtesy - Anders Röj, Volvo Technology Corporation, Fuels and Lubricants
Volvo Technology Corporation, Fuels and Lubricants
Future Fuels for Commercial Vehicles
Black liquor to engine fuels - Ideal use of low grade biomass
Pulp Mill
Green Liquor
Methanol/DME
Internal heat and power
Biomassfed power
boiler
BLGMF
AdditionalRenewable Energy
Pulp Wood
Pulp
Black Liquor
*
Production Efficiency =Methanol/ DME
Additional Renewable Energy> 65%*(Source:
Chemrec)
Center for Diesel Research
DME/Methanol Production Potential
• From black liquor gasification using existing pulp mills– Total use of black liquor in the mill
• Finland 50% transportation fuels• Sweden 30% transportation fuels• Minnesota 4 – 7% transportation fuels
– Adding a small booster plant to existing Minnesota mill• 7 million gallons per year DME – enough for about 700 urban buses
(MSP metro fleet ~ 900)• Or 7 million gallons per year methanol – enough to supply all the
methanol needed by all Minnesota’s biodiesel plants (6.3 million gallons) with some left over
• Estimated cost $2.20-2.30 / gallon gasoline equivalent with no subsidies
• Chemrec are talking to mill owners in the MN / WI region about building such a plant. They are carrying out a conceptual study for one of them.
Center for Diesel Research
DME/Methanol Production Potential
• Using not just pulp mills but all readily available biomass sources– NREL estimates that Minnesota has available biomass streams
the could produce the equivalent of 100-200% current gasoline use via gasification
– This would require a number of large gasification plants but could be a very long term sustainable solution
– It is likely that different states will have a different mix of long term renewable energy solutions. We will no longer have monolithic petroleum
• A likely path to DME introduction will be initial use as a propane replacement followed by gradual introduction of DME vehicles
• Production of “green methanol” for use in biodiesel production and for fuel cells may also play a role
Center for Diesel Research
Hybrid configurations
• A parallel hybrid uses power from an IC engine and an electric motor to drive the wheels
• A series hybrid uses power from the IC engine to drive a generator that supplies electricity for the electric motor to drive the wheels
• Plug-In hybrids use larger batteries to extend the range of the car minimizing the uses of the IC engine
• A series hybrid designs optimize engine performance but reduce vehicle performance