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Biofuel – what’s in it for rice farmers?. Some trends The maize – ethanol system Options for rice. Terminology. Bioenergy = Renewable energy produced from organic matter, i.e., solar-derived energy contained in biomass of living or recently living biological material.
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Some trends • The maize – ethanol system • Options for rice
Terminology • Bioenergy = Renewable energy produced from organic matter, i.e., solar-derived energy contained in biomass of living or recently living biological material. • Biofuel = Liquid, solid, or gaseous fuel produced by conversion of biomass. • Biopower = Direct use of biomass to generate electricity, heat or steam. http://bioenergy.ornl.gov/faqs/glossary.html
Biofuel categories • Produced from feedstocks contained within the food cycle: • Biodiesel: transesterification of plant-based oils • Canola, soybean, oil palm, coconut, jatropha • Bioethanol: sugar or starch conversion by fermentation • Sugarcane, sugar beet, sweet sorghum, maize, wheat, sorghum, cassava • Produced from non-food biomass: • Combustion (wood, crop residues, waste) • Gasification • Biomass to liquid (gasification/pyrolysis – liquefaction) • Biogas (anaerobic digestion) • Ligno-cellulosic ethanol • Ligno-cellulosic butanol
20-fold increase from 1850 to 2000. Fossil fuels supplied 80% of the world’s energy in 2000 (Holdren 2007)
Oil consumption in selected countries World energy demand is projected to increase by 50% by 2030.
Biofuel production is viable if crude oil prices stay above $55/barrel. Global vegetable oil production (150 Mt) = 10 d global fossil fuel consumption.
Plans for annual growth in biofuel production…2010/12 Costs of feedstock dominate costs Ethanol: 50-70%; Biodiesel: 70-80% Joachim von Braun, IFPRI, August 2007
“We can get fuel from fruit, from that shrub by the roadside, or from apples, weeds, saw-dust—almost anything! There is fuel in every bit of vegetable matter that can be fermented … And it remains for someone to find out how this fuel can be produced commercially—better fuel at a cheaper price than we know now.” Henry Ford, 1925 Not a new idea First corn-ethanol blended gasoline station, Lincoln, Nebraska, 1933
Gross energy yield of various biofuel crops * BD – biodiesel; E – Ethanol Crop yields: 2003-2005 average (FAOSTAT) Conversion yields: corn,0.399 L/kg; cassava, 0.137 L/kg; soybean 0.205 L/kg; rapeseed, 0.427 L/kg Liska and Cassman. 2007. J. Biobased Materials and Bioenergy
Gross energy yield and net GHG reduction estimates for food-crop biofuel systems Gross energy yield (GJ/ha) Gross energy values: two largest producers in the world Net GHG gas reductions: literature summary Liska and Cassman. 2007. J. Biobased Materials and Bioenergy
Impact on food prices • December 2006 – demonstrations in Mexico: rising tortilla prices due to rising corn prices • April 2007 - consumer food prices in the USA have increased 3-4% compared to one year ago • May 2007 – globally, milk powder price has risen 60% in 6 months; fluid milk 63% in one year • May 2007 – Indofood Sukses Makmut raises prices of instant noodles in Indonesia by 5% • September 2007 – rising food prices are a major cause of rising inflation in China • September 2007 - beer prices rise 5.5% at the Oktoberfest in Munich
Two examples • Technology options for optimizing maize-ethanol systems in North America • Biofuel options for rice systems in Asia
Expansion of USA maize-ethanol production 42% 34% % of maize production, assuming 34 Mha area harvested and trend- line yield increase 22% K. Cassman, Univ. of Nebraska
U.S. maize yields USA corn yield and irrigation (red hatched) by county (2004-2006 average). Source: National Agricultural Statistics Service, USDA. Liska and Cassman. 2007. J. Biobased Materials and Bioenergy
Maize-ethanol production life-cycle DISTILLATION GRAIN FERMENTATION ETHANOL DISTILLERS GRAINS wet dry CROP PRODUCTION
CO2 Maize & soybean production (1) Improve management (2) Increase NUE (10%) Ethanol plant (3) Starch content 7275% (4) Conversion efficiency 91 97% (enzymes, microbes) Ethanol Grain Distillers grain Thermal energy Stillage CH4 CO2 N2O CH4 Methane biodigestor (6) Closed-loop system (-56% energy) Cattle feedlot (5) Directly use wet distillers grain (-26% energy) Meat Manure, urine NO3 leaching Biofertilizer Technologies to improve maize-ethanol systems CH4 CO2 N2O NO3 leaching Grain A. Liska et al., UNL, 2007
Ethanol yield: crop management vs. other technological improvements CORN YIELD 7000 15.3 Mg/ha 6000 5000 Ethanol yield (L/ha) 4000 8.7 Mg/ha 3000 Yield NUE Genetics Engineering ALL 0 1 2 3 4 5 6 7 8 Technological improvements Black: National average yields and technology (Farrrell et al., 2006) Blue: High-yield irrigated corn-soybean system, CT A. Liska et al., UNL, 2007
Energy Ratio: 1.3-1.6 1.6 1.6 1.6 1.9 2.6 2.8 18 16 14 Net Energy Value (MJ/L) 12 10 8 Yield NUE Genetics Engineering ALL 6 0 1 2 3 4 5 6 7 8 Technological improvements Black: National average yields and technology Blue: High-yield irrigated corn-soybean system, CT Ethanol biorefinery integration with livestock to avoid drying distiller’s grains and producing methane can DOUBLE corn-ethanol’s net energy efficiency. A. Liska et al., UNL, 2007
GHG emissions reduction (% and t CO2eq*) Maize production system Ethanol biorefineries *Based on a 100 million gal/yr production capacity A. Liska et al., UNL, 2007
First Commercial-Scale Closed Loop Biofuel Refinery, Mead, Nebraska www.e3biofuels.com Ethanol: 24 M gallons/yr Cattle: 28,000 head/yr
Breakeven price for ethanol in the USA to compete with petroleum, given current subsidies Feb. 2007 Oct. 2007 Feb. 2006 • Petrol @ $50/barrel: • - to be competitive with gasoline ethanol needs to sell for $1.55/gal (incl. $0.51/gal subsidy) • Plant operating costs $0.55/gal + $0.30/gal capital cost - $0.10/gal federal subsidy • max. corn price to break even: $1.55 – 0.85 + 0.10 = 0.80/gal = $3.20/bushel R. Perrin, Univ. of Nebraska, Feb. 2007
Rice area Rice production Includes forecast for 2007 (FAO Rice Market Monitor, Sep. 2007)
Rice grain should not be used for biofuels Riceland should not be converted to biofuel crops
Rice hulls • 100 kg of paddy rice 20 kg of hulls during milling • >110 million tons annually collected at rice mills • ~10% moisture • Bulk density 100 to 150 kg/m3 • Energy content: 14-16 MJ/kg (dry wood: 18-20 MJ/kg) • Main carbohydrates: cellulose and lignin • 16 to 22% ash, 90-96% of the ash is silica • Higher ash melting point than ash from rice straw - less slag deposits when burned for fuel
Straw as a new income source for rice farmers? • 580 million tons of rice straw per year • 35-40% C, 0.5-0.8% N, 1.2-2.0% K, 4-7% Si • Current use: burning, removal (fuel for cooking), some incorporation, some for other uses • Energy content: 14 MJ/kg at 10% moisture
In what systems can crop residues be removed without threatening long-term sustainability? In irrigated rice monoculture systems, removal of straw does not cause a decline in soil organic matter. R. Buresh (IRRI) & K. Sayre (CIMMYT)
Seasonal rice straw availability in Thailand Dry Season 2006 (kt straw) Wet Season 2006 (kt straw) B. Gadde, JGSEE Bangkok
As intermediate steps increase – efficiency goes down Thermal conversion Straw conversion to biopower or biofuel Straw Mandatory step Harvest Collection Baling Transport Raw material processing Form as Shredded Briquetting received Hydrolysis Energy conversion Combustion Pyrolysis Gasification Biomethanation Fermentation Intermediate energy form Liquid Gas Solid Form of end use Electricity Heat Liquid fuel Gaseous fuel Slightly modified from C. Menke, JGSEE Bangkok
Thermal conversion technologies Excess air and heat Partial air, ~700 °C No air, 200-500 °C Combustion Gasification Pyrolysis Heat Ash Syngas Bio-oil Gases Charcoal Steam Electricity Liquid fuels • Local electricity generation as the major target • Applicable across a wide-range of sizes: 5 kW to >5 MW • Centralized or decentralized • Can use a wide range of biomass feedstocks • Moderate to high savings in net GHG equivalents
Biopower from thermal straw combustion • Denmark: 75 straw-fired plants (11 heat + power) • India: First 10 MW straw combustion plant built in 1992 (Punjab); many operational problems; 17 new 12 MW rice straw power plants planned for Punjab and Haryana (first in 2008) • China: 6 straw power plants in Jiangsu (2 operate), 24-30 MW each; source straw within 25-50 km, need about 150-200,000 t straw/year. More are planned. • Technical problems: high alkali content of straw • High Si content of rice ash leads to a low melting point and formation of alkali deposits • Corrosion and fouling problems in the superheater • Logistics of feedstock supply and storage (safety) Gadde et al., 2007
China’s first biopower plant using 100 % crop straw Prof. Cheng Xu, CAU
Gasification and pyrolysis • Well known technologies • Rice hulls and rice straw are suitable (>20% lignin) • Little work on low density feedstock such as straw • Pyrolysis: T and residence time can be varied to produce different proportions of end products: 10-85% gas, 5-75% bio-oil, 10-35% bio-char • Technical problems: • Size reduction, drying & compaction • Alkali deposits and ash melting (straw gasification) • Gas cleaning (tar and particle removal) and conditioning • Mostly for energy needs of a small industry or few hundred homes; charcoal production Gadde et al., 2007
Industrial scale rice hull gasifiers Riceland Foods, Inc., Stuttgart, Arkansas 525 t rice hulls/day 15 MW electricity Cargill Rice Milling Greenville, Mississippi 330 t rice hulls+straw/day 6.5 MW electricity + steam for parboiling facility
What’s in it for rice farmers? • Indirectly: increased income through stable or rising grain prices (pressure on land) • Income from selling rice hulls and straw • Shareholder arrangements (ownership in village-level biopower plants) • Payments for carbon credits through Clean Development Mechanisms
Research needs for utilizing rice straw • Short-term: • Adapt thermal conversion technologies: reduce ash melting in combustion/gasification, tar removal from Syngas, gas conditioning, co-firing of rice hulls + straw • Fully operational village scale solutions • Biomass supply and processing chains • LCA of thermal conversion solutions • Payment schemes, including payments for C credits • Long-term: • BTL process • Ligno-cellulosic conversion to ethanol or butanol • Physical and chemical straw characterization & breeding for straw conversion traits (Si, Cl, K, lignin, brittle straw)
Summary • Biofuels will stay, accelerate globalization of ag, increase crop prizes, and raise land values. • Technology advances made in developed countries may not benefit the developing world. • Key risks: food price increases and instability & wrong policies. • Subsidies for biofuels are anti-poor. Need to establish a transparent global market and trade regime. • Rice farmers may benefit, but policy makers need to protect the poor from rising commodity prices. • Decide based on unbiased information on life cycle performance and impact of crop-biofuel systems. • Asia: utilize crop residues that can be safely removed, especially rice straw.