Download presentation
Presentation is loading. Please wait.
Published byPresley Eggleston Modified over 9 years ago
1
Biofuels
2
Why are biofuels attractive? Energy security: locally produced, wider availability, “grow your own oil” Climate change mitigation: one of the few low- carbon options for the transport sector Lower emissions of various harmful pollutants (e.g., sulfur) Liquid fuels: conducive to existing infrastructure, storage, distribution –Bioethanol: cars, light trucks, motorcycles –Biodiesel: commercial vehicles, buses, pumps, isolated electricity generation
3
Biofuel production Ethanol –Sugarcane (Australia, Brazil, China, Colombia, Ethiopia, India, Thailand), sugar beets (EU) –Maize / Corn (US, China) –Wheat (Canada, EU) –Cassava (Thailand) –Biomass wastes (cellulose): forest products (Canada), wood wastes, agricultural residues—maize stover, sugarcane trash –Energy crops—switch grass, hybrid poplar, willow Biodiesel –Rapeseed (EU) –Soybeans (US) –Palm oil (Malaysia) –Coconut oil (Philippines) –Plants growing on ‘marginal’ land—Jatropha, Karanja (India)
4
USDA, July 2006
6
Greenhouse Gases: We burn fossil fuel (coal, oil = fossilized plants and microscopic algae) MUCH faster than it is formed - Middle East oil: ~ 110 million years old; US coal: ~ 320 million years old. CO 2 + H 2 O -> CH 2 O + O 2 (photosynthesis); reverse reaction-burning, decay respiration Biofuels: every year ‘burn as we grow’ - crops pick up CO 2 in photosynthesis, we put it back by burning -> no net effect on concentration of greenhouse gases
8
Things to consider: Alternative fuel: what are its TOTAL ‘costs’? –Example: hydrogen-powered cars: what does it cost (energy, environmental) to make the hydrogen? Biofuels: energy costs of growing include watering, fertilizer production, transport of fertilizer and crop, costs of seed grain, cost of government subsidies, environmental pollution clean-up, income from byproducts Other factors: job creation, competition with food production, environmental pollution through fertilizer use, and so on
10
Does it take more energy to make ethanol than is contained in the ethanol? SIMPLIFIED 1980: yes 1990: probably not 2005: no the ethanol industry, in terms of energy use per gallon of ethanol produced, has become much more efficient over the years, as has the farmer, in terms of energy use per bushel of corn grown
14
Efficiency: 1. Yield of ethanol per acre 2. Net energy yield (ratio of energy in / energy out) 3. Expenses as compared to that of gasoline derived from oil, combined with miles/gallon (cars need ~ 30% more ethanol than ‘normal’ gas per mile driven)
15
1 acre sugar beets: ~ 720 gallons 1 acre sugarcane: 695 -720 gallons of ethanol 1 acre of corn: 350-420 gallons of ethanol 1 acre of sorghum: 172 gallons of ethanol
16
USDA, July 2006
17
Energy ratios: Corn to ethanol: ~1.3 (mean current techniques) to ~ 1.7 (best present techniques) Cellulose ethanol: use enzymes to digest cellulose) - not yet fully functional. Estimated: ~3-6 Sugar cane - sugar beets: ~6-8 (including energy generated through byproduct burning) Difference in fermentation processes of starch (in corn) and sucrose (in sugar crops): higher efficiency of sugar
18
COSTS World raw sugar vs. gasoline price Rotterdam unleaded regular gasoline 4Q 2005 US dollars Source:Worldbank
19
COSTS Brazil: world’s lowest-cost sugar producer Favorable climate, plentiful land, good soil, and abundant rainfall in Center-South (cane cultivation water intensive) Use of bagasse for plant energy use and surplus electricity sales Between 1975-2000, sugarcane yield per hectare increased by 33%, sugar content of cane 8%, ethanol yield from sugar 14%, fermentation productivity 150% Modern sugar production and processing and high level of managerial skills –More than 500 commercial varieties of cane (each plant processes around 15 varieties) –Hybrid sugar mill/distillery complexes –Planting, harvesting, and plant operations computerized
20
Source: USDA 2002 Brazilian ethanol is cheapest
21
Sugarcane-ethanol: Advantages Higher ethanol yield per acre Lower energy costs Higher net energy balance Bagasse is used for production of steam & power Could received 2.5 credits for every gallon Lower Volatile Organic C emissions
22
Sugarcane-ethanol: Disadvantages (production within US) Higher feedstock costs Higher cane transportation costs Higher processing costs Higher labor use and labor costs Higher expenses for repairs, maintenance, and parts Higher expenses for general and administration
23
Source: Brazilian Government
26
Prospects for biofuels Near term Ethanol from sugarcane: best overall chance of commercial viability Biofuel trade liberalization beneficial to all consumers Biodiesel remains expensive relative to world oil prices Medium term Fall in production costs New feedstocks Growing trade Long term Commercialization of cellulosic ethanol: widespread availability, abundance, and significant lifecycle GreenHouse Gas emission reduction potential Higher oil prices favoring biofuel economics Source:Worldbank
27
In Summary: Significant use of biofuel-ethanol will reduce emissions of greenhouse gases significantly Corn ethanol production IS energy efficient Sugar-crop ethanol production (within US) is more efficient than corn ethanol production (BUT: climate, water availability, costs) Import of ethanol from Brazil would lower costs for consumers in the US if sugar tariffs are abandoned/ lowered (globalization) - no benefits for US farmers Further research is needed to investigate production of cellulose - ethanol (bacterial enzyme action) and other compounds (butanol)
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.