Biofuels: past, present and future?

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Hester Golden
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1 Biofuels: past, present and future? The Nexus of Biofuels Energy, Climate Change and Health January 24, 2013 Roger C. Prince ExxonMobil Biomedical Sciences, Inc. This presentation includes forward-looking statements. Actual future conditions (including economic conditions, energy demand, and energy supply) could differ materially due to changes in technology, the development of new supply sources, political events, demographic changes, and other factors discussed herein (and in Item 1 of ExxonMobil s latest report on Form 10-K). This material is not to be reproduced without the permission of Exxon Mobil Corporation.

2 Global Progress Drives Demand Population Billion Average Growth / Yr % GDP Trillion 2005$ Average Growth / Yr % Energy Demand Quadrillion BTUs 1400 Average Growth / Yr % Energy Saved ~ Non OECD OECD

3 Diverse Fuel Mix Meets Demand Primary Energy Renewables Wind, Solar, & Biofuels Quadrillion BTUs Quadrillion BTUs Quadrillion BTUs Renewables Nuclear 80 Wind, Solar, & Biofuels 20 Solar Coal 60 Hydro / Geo Gas Wind 200 Biomass 100 Oil 20 5 Biofuels

4 Energy Use Evolves Over Time Global Percent Mix of Fuels Percent 100 Other Renewables 80 Nuclear Hydro Gas Oil 20 Coal Biomass Smil, E. (2010) Energy Transitions: History, Requirements, Prospects 4

5 Substantial Regional Differences 740,000 BTU per day = 217 kwh = 789MJ = tonnes coal = barrels oil = 5.4 gallons gasoline PER DAY A human consuming 2000 (k)calories/day 8000 BTU 3 horsepower-hours 5

6 Energy Use Will Grow Globally, about 1.5 billion people have no access to electricity 2.5 billion people use primitive cooking and heating fuels 6

7 World Energy Supply MIT View MBDOE MIT 550 ppm GHG Stabilization Scenario Emerging Low GHG Energy Fossil Fuels with CCS Bioenergy Nuclear Other Renewables Efficiency & Demand Reduction Fossil Fuels Significantly altering energy supply is a long term process 7

8 How Productive Is The Earth? Net Primary Productivity (NPP) of the planet is the amount of photosynthetic biomass available for exploitation by the biosphere Plant photosynthesis minus plant respiration Terrestrial NPP about 56 Gtonnes/yr Humans already appropriate a large fraction of NPP estimates cluster around 30% So any increase in this appropriation for biofuels will have to be very efficient And of course NPP does all get used today any increase in human use WILL take away from other ecosystem processes And realistically biofuels on a significant scale cannot compete with food or for potable water There is a possibility that crops such as algae could be grown where currently there is minimal NPP Field et al. (1998) Science 287: 237 Erb et al. (2009) Ecological Economics, 69: 250 8

9 First generation biofuels Ethanol from sugar and starch Sugar cane in Brazil, corn in the US, wheat and sugar beet in the EU, cassava in the tropics Biodiesel from oil seeds Soybean in the US, rapeseed in Canada and the EU, palm in the tropics 9

10 Current ethanol efficiency Very disappointing as a solar conversion: Brazil 0.14% US 0.03% Generally agreed about a 30% energy profit in the US Need to produce 4 liters on the farm/distillery to export 1 liter if the goal is no fossil input Equivalent weight of animal food But corn production causes substantial soil loss >4kg soil per liter of ethanol Kheshgi, H. S., Prince, R. C. and Marland, G. (2000) The potential of biomass fuels in the context of global climate change: focus on transportation fuels. Ann. Rev. Energy. Environ. 25,

11 Brazil s Ethanol Could Be Carbon Negative Fermentation produces a pure CO 2 stream, one mole per mole of ethanol If that were sequestered, the net effect could pump CO 2 from the atmosphere as the ethanol was used as fuel Pilot project at the ADM distillery in Decatur Il tonnes CO 2 per day 1995 Ethanol USA corn Brazil Sugar Cane Units Ethanol Yield L/ha/yr Full fuel cycle CO 2 emissions Mg CO 2 /ha/yr Gasoline Offset Mg CO 2 /ha/yr How much better than gasoline? Mg CO 2 /ha/yr With Sequestration of Fermentation CO 2 Fermentation CO Mg CO 2 /ha/yr Compressor Power (1-60 bar) Mg CO 2 /ha/yr Full Fuel Cycle CO 2 Emissions Mg CO 2 /ha/yr How much better than gasoline? Mg CO 2 /ha/yr Kheshgi, H.S. and Prince, R.C. (2005) Sequestration of 11 fermentation CO 2 from ethanol production Energy 30;

12 Biodiesel Yields much less than corn ethanol US 50 gallons per acre biodiesel compared to 250 for ethanol Oil about 20% of the bean Pressed cake to animal feed Soy farming also a substantial cause of soil erosion 28 kg per liter of biodiesel 12

13 First Generation Biological Conversions Sugars are amenable to several transformations Anaerobic + Classical ethanol fermentation (yeasts, Zymomonas, etc.) + Acetone-Butanol-Ethanol fermentation Clostridium + Isobutanol fermentation Engineered yeasts Aerobic + Algal and yeast lipids by heterotrophic growth Chlorella, Crypthecodinium + Farnesene fermentation Engineered yeasts But this currently requires low-cost, reasonable-purity glucose Corn syrup works well, but is unlikely to be economic in the long term Several companies moving to Brazil for sugarcane 13

14 Second Generation Biological Conversions Will require much cheaper and more abundant sources of glucose Cellulose and hemicellulose from digestion of cellulosic biomass + Crop residues or specially grown crops Several major challenges Crop supply + Highest producing grasses and trees not yet farmed + Crop densities preclude long distance shipping Recalcitrant substrate + Cellulose intimately associated with lignin + Separation processes tend to generate microbial inhibitors Novel biochemistry + Cellulose has equimolar pentoses 14

15 Many Bio-energy Pathways Emerging sun + CO 2 + water biomass algae gasification anaerobic conversion methanol unit power plant MTG pretreatment hydrolysis fermentation bio-oil production bio-oil conversion electricity and heat bio-gas gasoline cellulosic ethanol gasoline diesel Today Long term Time 15

16 Biofuel Productivity Map shows land area required for biofuel production equivalent to 0.1% of total US road transportation demand (light and heavy duty) Based on current and projected biofuel productivity (gallons/acre-yr) rates Washington, DC Legend Soybean (4791 sq mi) Corn (958 sq mi) Sugar Cane (532 sq mi) Palm (369 sq mi) Algae (110 sq mi) 10 miles 16

17 The Future For Biofuels? At the end of the day, the question is whether biofuels can be produced on a large enough scale that they significantly impact global or national energy use. The world uses about 45 million barrels of oil equivalent per day for transportation expected to grow to 65 million barrels per day in 2040 US gasoline demand is million barrels per day US distillate (diesel + heating oil) demand is million barrels per day And can biofuels be produced with an acceptable environmental impact? 17

From Biomass. NREL Leads the Way. to Biofuels

From Biomass. NREL Leads the Way. to Biofuels From Biomass NREL Leads the Way to Biofuels The Wide World of Biofuels Fuel Source Benefits Maturity Grain/Sugar Ethanol Biodiesel Corn, sorghum, and sugarcane Vegetable oils, fats, and greases Produces