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Renewable Energy: Biomass and Bioenergy
Jürgen ScheffranInstitute of Geography, CliSAP/CEN
Universität Hamburg
“Energy Landscapes and Climate Policy" (63-951) Lecture 4, May 12/26, 2016
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Renewable energy
Renewable energy (REN): from natural (re)sources such as sunlight, biomass, wind, rain, tides and geothermal heat which are renewable naturally replenished.
REN flows derived from natural processes that are replenished constantly, directly from the sun, or from heat generated deep within the earth, including electricity and heat generated from solar, wind, ocean, hydropower, biomass, geothermal resources, and biofuels and hydrogen derived from renewable resources.
REN technologies: intermittent, land consuming, environmental impacts, distributed.
REN policies driven by climate change concerns and high oil prices, peak oil, and increasing government support
REN targets: exist in more than 70 countries
New government spending (subsidies to users and suppliers), regulation and policies
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Earth’s energy cycleFrom: Rose (1986) Learning about Energy,Plenum Press, New York.
p. 4IPCC (2011) SRREN_SPM
Special Report on Renewable Energy Sources and Climate Change Mitigation (IPCC-SRREN, May/June 2011)
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IPCC-SRREN (2011) conclusions on bioenergy
•Bioenergy technologies can generate electricity, heat and fuels from a range of ‘feedstocks’.
•Some bioenergy systems, including ones that involve converting land into agricultural biomass and energy crops, can generate more greenhouse gas emissions than they save.
•But others, such as advanced conversion systems, which for example convert woody wastes into liquid fuels, can deliver 80 to 90 percent emission reductions compared to fossil fuels.
•Bioenergy, mainly for traditional cooking and heating in developing countries, currently represents over 10 percent of global energy supply or ca. 50 Exajoules (EJ) per year.
•While the share of bioenergy in the overall renewables mix is likely to decline over the coming decades, it could supply 100 to 300 EJ of energy by 2050.
IPCC-SRREN press release
p. 6IPCC (2011) SRREN_SPM
Historical development of global primary energy supply from renewable energy from 1971 to 2008
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Shares of energy sources in total global primary energy supply in 2008
IPCC (2011) SRREN_SPMWorld total primary energy supply: 492 ExaJouleModern biomass contributes 38% of total biomass share
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Shares of global primary biomass sources for energy
Source: IPCC-SRREN (2011)
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Global primary production of biomass
SeaWiFS Project, NASA/Goddard Space Flight Center and ORBIMAGEThe normalized difference vegetation index (NDVI) is an estimate of the photosynthetically absorbed radiation over the land surfaces.
NASA Goddard Spaceflight Center
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Formation and composition of plant matter
Source: Kaltschmitt et al, Renewable Energy, 2007
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Materials balance of a hornbeam forest in atemperate climate
Source: Kaltschmitt et al, Renewable Energy, 2007
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Plant efficiencies
Source: Sorensen
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Factors in plant growth
Solar radiation Temperature Precipitation Evaporation
Soil waterGrowing season
Degree days
Leaf expansion index
Photosynthesiswater stress
Leaf expansionWater stress
Photosynthesis
Dry matter Yield output
Adapted from Clifton-Brown’s MISCANMOD
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Net productivity of forests depending on precipitation and temperature
Source: Kaltschmitt et al, Renewable Energy, 2007
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Plant types
C3 Photosynthesis/C3 plants. Most plants are C3.
•Called C3 because the CO2 is first incorporated into a 3-carbon compound.
•Stomata are open during the day, Photosynthesis takes place throughout the leaf.
•RUBISCO enzyme involved in photosynthesis is also involved in the uptake of CO2.
•Adaptive Value: more efficient than C4 and CAM plants under cool and moist conditions and under normal light, requires less machinery (fewer enzymes and no specialized anatomy)
C4 Photosynthesis / C4 plants: several thousand species, at least 19 plant families. Example: corn, many summer annual plants.
•Called C4 because the CO2 is first incorporated into a 4-carbon compound.
•Stomata are open during the day. Photosynthesis in inner cells
•Uses PEP Carboxylase for enzyme in uptake of CO2, allows to take CO2 into the plant very quickly, then "delivers" CO2 directly to RUBISCO for photsynthesis.
•Adaptive Value: Photosynthesizes faster than C3 plants under high light intensity and high temperatures; better water use efficiency
CAM Photosynthesis : CAM plants (Crassulacean Acid Metabolism) include many succulents such as cactuses and agaves and also some orchids and bromeliads
CO2 is stored in the form of an acid before use in photosynthesis.
Stomata open at night (when evaporation rates are lower), usually closed during the day.
Adaptive Value: Better Water Use Efficiency than C3 plants under arid conditions due to opening stomata at night when transpiration rates are lower
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Photosynthetic rates of C3 and C4 plants
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Average corn yields in the United States
Troyer, 1990Source: Troyer, 1990
1 US bushel = 35.2 litre1 acre = 4,047 square metres (0.405 hectares)
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Projected US corn yield increases
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Grain yield of predominantly rainfed maize
Source: Rockström 2009
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Geographic distribution of technical energy potentials of solid biomass fuel
Adapted from: Kaltschmitt et al., 2003, p. 48
Source: Kaltschmitt 2003, Energiegewinnung aus Biomasse.
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Map of biomass productivity
Bazilevich 1994
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Biomass resources in the USA
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Energy uses of biomass
Biomass
Burn produce electricity
Thermochemicalconversion to
syngas products
Biochemicalconversion toethanol and other fuels
Mature Semi-mature(Capital intensive
inefficient)
In development
Source: Steve Long
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Enough biomass to fill the tank on the truck with bioethanol…...
Source: Paul Carver, 2007
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…..45 minutes fuel for a coal fired power station
Source: Paul Carver, 2007
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Typical oil extractable from crops (by weight)
Crop Oil %copra 62castor seed 50sesame 50groundnut kernel 42jatropha 40rapeseed 37palm kernel 36mustard seed 35sunflower 32palm fruit 20soybean 14cotton seed 13
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Perennial grasses
Courtesy: D.K. Lee 2008
Switchgrass (Panicum virgatum L.) Miscanthus x giganteus
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Energy content of biomass vs. coal
Heating Value (GJ/t)
Ash (%) Sulfur (%)
Miscanthus 17.7-18.9 1.5 - 4.5 0.1
Switchgrass 18.3 4.5 - 5.8 0.12
Corn Stover 17.6 5.6
Coal 20-30 1 - 20 0.5 - 3
Source: Madhu Khanna, Basanta Dhungana, Michelle Wander, Miscanthus: A Sustainable Source of Energy?, 2004, Dept. of Agricult. & Consumer Economics, Dept. of Natural Resources & Environmental Sciences, University of Illinois Urbana-Champaign
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Solar energy collection of biomass and fossil fuel energy requirements
ODT: Oven Dry TonsLocation: Ontario crops, SourceL Samson et al 2008
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Estimated per-acre ethanol yields for various crop types
Farell et al,2007
1 US gallon = 3.78 liters
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Conversion routes of bioenergy
Commercial routes (solid lines), developing bioenergy routes (dotted lines)(1) Parts of each feedstock could also be used in other routes. (2) Each route also gives coproducts. (3) Biomass upgrading includes any one of the densification processes (pelletization, pyrolysis, torrefaction, etc.). (4) Anaerobic digestion processes release methane and CO2 and removal of CO2 provides essentially methane (5) Could be other thermal processing routes such as hydrothermal, liquefaction, etc. DME=dimethyl ether.
(Source: SRREN 2011, modified from IEA Bioenergy 2009)
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ConversionProcesses
– Trees – Grasses– Agricultural Crops– Agricultural Residues– Animal Wastes– Municipal Solid Waste
USESFuels:– Ethanol– Renewable Diesel
Power:– Electricity– Heat
Chemicals– Plastics– Solvents– Chemical Intermediates– Phenolics– Adhesives– Furfural– Fatty acids– Acetic Acid– Carbon black– Paints– Dyes, Pigments, and Ink– Detergents– Lubricants– Etc.
Food and Feed and Fiber
- Enzymatic Fermentation- Gas/liquid Fermentation- Acid Hydrolysis/Fermentation- Gasification- Combustion- Co-firing
BiomassFeedstock
… and new concepts from plants to products
Biorefinery and the new bio-economy
Source: Stanley R. Bull, NREL
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Electricity generation from biomass in selected countries
Source: Global Energy Assessment 2012
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Ethanol production from sugar and starch crops
Source: Global Energy Assessment 2012
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Global production of biodiesel (2000–2007)
Source: WBGU 2009
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Fat for Fuel: Eco Taxi Berlin
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Motivations for biofuels
Energy security: Growing oil prices and dependence on energy imports from the Middle East increase demand for renewable energy
Home-grown domestic energy sources offer development perspectives to structurally weak rural areas and lead to structural changes in land-use and agriculture
Economic benefits: more than 200,000 new jobs, increase of GDP by US$ 200 billion between 2005-2012, increase of farmer's income by US$ 43 billion (Renewable Fuels Association 2006)
Sustainable development in Third World: growing energy demand in developing countries; high productivity of energy crops in tropical and subtropical regions, employment and income in rural areas
Low-carbon energy alternatives to fossil fuels: carbon emission reductions for current biofuels vary between 30% and 80% for current generation; much higher reduction for second generation (cellulosic).
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Biofuels and climate policy
In his State of the Union speech, George W. Bush set a target to boost ethanol and other alternative fuel production to 35 billion gallons a year by 2017 – a fivefold increase.
The March 9, 2007 deal between the United States and Brazil on biofuels satisfies the growing US demand in ethanol.
European Union leaders at a climate change summit in Brussels March 9, 2007 have agreed to slash carbon dioxide emissions by 20% from 1990 levels by the year 2020.
These cuts would rise to 30% if the United States and other industrialized countries were to commit themselves to 'comparable' emissions cuts after 2012, and if large developing countries including China contribute 'adequately'.
The European Commission wants countries to pledge, among other things, to raise use of renewable fuels to 20%.
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Required growth of cellulosic Ethanol to supply 30% of U.S. Gasoline demand by 2030
Grain Ethanol and Vegetable Oil Biodiesel0
10
20
30
40
50
60
70
Bill
ion
Gal
lons
/Yea
r
Grain Ethanol and Conventional Biodiesel
Cellulosic Ethanol and "Green" Diesel
2015 2025 203020202005 2010
3.7
44.8
9.412.8
Source: Stanley R. Bull, NREL
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Global Technical Bioenergy Potential by main resource category for the year 2050
IPCC 2014
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Experience curves for the cost of sugarcane-based ethanol production (logarithmic scale)
IPCC (2011) SRREN_SPM
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Selling price for ethanol in Brazil vs. cumulative productioncompared with Rotterdam price for gasoline
Source: Global Energy Assessment, based on Mytelka and de Sousa Jr., 2011
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Production costs for selected biofuels 2004–2007 in main production countries
WBGU 2009
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Costs in 2002 Dollars
$0.00
$1.00
$2.00
$3.00
$4.00
$5.00
$6.00
2000 2005 2010 2015 2020
Min
imum
Eth
anol
Sel
ling
Pric
e ($
per
gal
)
Enzyme
Conversion
Feedstock
Current DOE Cost Targets
Secretary's Biofuels Initiative
State of Technology EstimatesFeed $53 per ton
2005 Yield65 gal/ton
Feed $30 per tonYield 90 gal/ton
Feed $30 per tonYield 94 gal/ton
10 000 TPD
DOE Cost
TargetDOE Cost
Target
Feed $45 per tonYield 75 gal/ton
Biofuels cost targets
Source: Stanley R. Bull, NREL
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Biofuel Lifecycle
CABER 2007
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Critical issues of biofuels
Energy balance
Carbon balance
Land use
Competition with food
Water needs
Fertilizer and chemical inputs
Biodiversity, monoculture, invasive species
Safety and security
Cost of harvest and distribution
Jobs
Subsidies
Legal issues
Comprehensive Life-cycle Assessment for sustainable biofuels
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Differences in the biofuels debate
Biofuels:
are essential or insignificant for energy security?
reduce or increase GHG emissions?
have positive or negative energy balance?
increases or decreases poverty?
are a significant or negligible factor in rising food prices?
are significant or negligible in creating jobs?
are competitive or not competitive with fossil fuels?
are sustainable or not sustainable?
have positive or negative impacts on human security?
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Indoor levels of particulate concentrations emitted from wood fuel combustion in selected developing countries
Source: IPCC 2007:WG3, based on Karekezi and Kithyoma, 2003.
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Ethanol: From corn to fuel
In 2006, 17 percent of the corn crop was processed into ethanol which accounted for 2 percent of fuel supply.
Technology Review, Jan. 2008
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Lifecycle fossil energy use estimates in production of several first generation biofuels and two petroleum fuels
Source: Global Energy Assessment 2012
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Estimated life-cycle GHG emissions for first-generation biofuels, excluding any impacts of land use change
Source: Global Energy Assessment 2012
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GHG mitigation potential and biomass yield
0
2000
4000
6000
8000
10000
12000
0 5 10 15 20 25 30
Biomass yield, metric t/ha/yr
Avo
ided
GH
G e
mis
sion
s, k
gCeq
/ha/
yr
Corn ethanol, 2005
Woody & herbaceous cellulosic ethanol, 2005/2010
Herbaceous cellulosic ethanol, 2025
Herbaceous cellulosic ethanol, 2050
Brazil sugarcane, best practice 2002 (68.7 t/ha/yr of raw cane stalks)
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Energy ratio and carbon emissions of ethanol
Technology Review, Jan. 2008
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Land requirements for producing bio-fuels for half current U.S. passenger fleet
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Direct effects of biofuels
• Habitat destruction (particularly in Amazonia for soy and South-East Asia for palm oil)
• Local environmental impacts upon air, water and soil quality and exacerbation of local water supply concerns
• Social issues including poor working conditions for laborers and reported loss of land rights for indigenous peoples where new plantations for feedstock are established.
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Indirect effects
Rising food prices and the effect upon food security for the poor
Displacement of agricultural production onto uncultivated areas with impacts on biodiversity, GHG savings and local land rights as a result of biofuel production.
Many forms of land-use change result in significant releases of carbon to the atmosphere (payback time), negating any benefits (compared to petrol).
Examples:Expansion of sugar cane production in Brazil, leading to displacement of cattle ranching and accelerated deforestation in Amazonia.
Expansion of soy production in South and Latin America as a consequence of US farmers increasing production of maize (and reducing production of soy)
Increased demand and prices for oil seed rape for biodiesel in the EU leads to expansion of palm oil production in South-East Asia.
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Land availability
Idle land:
• Former or current agricultural land that will not otherwise be used for food production; and
• Land that is potentially suitable for agricultural production.
Marginal or degraded land:
• Land unsuited for food production, e.g. with poor soils or harsh weather environments; and
• Areas that have been degraded, e.g. through deforestation.
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Illustrative GHG savings and payback times for biofuel feedstock causing land change
Source: Gallagher Review 2008, based on E4Tech 2008
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Sustainable biomass standards
Source: Eco Institute 2006
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Roundtable on Sustainable Biofuels
Multinational effort involving some of the world’s largest biofuel purchasers, bioenergy producers, and a variety of other civil society interests.
Open to anyone who wants to participate www.bioenergywiki.net
Roundtable and its standards shall “create a tool that consumers, policy-makers, companies, banks, and other actors can use to ensure that biofuels deliver on their promise of sustainability”
Umbrella for the many commodity-specific sustainability standards that would apply to specific biofuels feedstocks (e.g. palm oil, soy, sugar cane, jatropha).
Third-party certification to RSB criteria serves as purchasing guideline for industry to use of best practices in the social and in environmental realm.
TBT Agreement does not define “international standard,” but it establishes criteria for international standards body.
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Roundtable on sustainable biofuels steering board
UNEP
Brazilian environmental and social NGO’s
BP
Bunge Corporation
Dutch Ministry of Housing and the Environment
The Energy Resources Institute (TERI) of India
Swiss Federal Institute of Technology (EPFL)
Federation of Swiss Oil Companies
Forest Stewardship Council
Keio University, Japan
Mali Folkecenter
Pinho, Petrobras
Volkswagen Environment
National Wildlife FederationShell OilSwiss Energy MinistryToyota Motor EuropeUNCTADUN FoundationUniversity of California at BerkeleyWorld Economic ForumWWF International Working Groups’ ChairsMichigan State UniversityIUCN, National African Farmers’ UnionGerman NGO ForumVirgin Group.
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Multi-stakeholder standards-setting processes
Roundtable on Sustainable Palm Oil (RSPO)
Roundtable for Responsible Soy (RTRS)
SA 8000: developed by Social Accountability International (SAI)
Global Social Compliance Program (GSCP): initiative of CIES, InternationalCommittee of Food Retail Chains, Food Business Forum.
Fairtrade
Rainforest Alliance
GlobalGap
International Federation of Organic Agriculture Movements (IFOAM)
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Suggested criteria for sustainable development design
Environmental criteriaFossil Energy ResourcesAir QualityWater QualityLand Resources
Social criteriaStakeholder ParticipationImproved Service AvailabilityCapacity DevelopmentEqual Distribution of Project Return
Economic criteriaMicroeconomic EfficiencyTechnology TransferRegional EconomyEmployment Generation
Other criteria
Sufficient water supply
Avoid land use conflicts
Biodiversity and wildlife protection
Mitigation of and adaptation to climate change
Macro-economic benefits
Development potential
No resource exploitation
True cooperation
Low conflict potential
Political stability
DemocratizationSource: Sutter 2003, in MED-CSP
Feedstocks
Harvesting
ProcessingDistribution
UtilizationBiofuel
Lifecycle
New varietiesGenomics
Pest controlLand use
TechnologyMachinery
LaborLogistics
Transportation
DeconstructionMicrobes
FermentationCoproducts
Industry
LogisticsTransportation
Industry StructureResource recovery
Engine technologyConsumer demand
Recycling
TechnicalFeasibility
EconomicViability
EnvironmentalSustainability
Social-politicalAcceptability