anthropogenic co2 as a feedstock for cyanobacteria-based biofuels pradeep...
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Anthropogenic CO2 as a Feedstock for Cyanobacteria-Based Biofuels Pradeep Sharma, Ryan P. Lively, Benjamin A. McCool and Ronald R. Chance
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Cyanobacteria-based (“Advanced”) Biofuels
• Biofuels in general
• Risks of climate change has made the
global energy market very carbon-
constrained
• Biofuels have the potential to be nearly
carbon-neutral
• Advanced biofuels
• Energy Independence & Security Act (EISA)
requires annual US production of 36 billion
gallons of renewable fuels by 20221,2
• Corn-based ethanol may peak out around 15
billion gal/yr
• Advanced biofuels technologies, such as
Algenol’s Direct to Ethanol®, have the
potential to fill the gap
• Algenol intends to compete on price
regardless of mandates and a reduced RFS
1EISA, http://www.gpo.gov/fdsys/pkg/PLAW-110publ140/html/PLAW-110publ140.htm 2US EPA Renewable Fuel Standards, http://www.gpo.gov/fdsys/pkg/FR-2013-08-15/pdf/2013-19557.pdf
CO2 H2O
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Algenol’s Direct To Ethanol®
2 CO2 + 3 H2O
C2H5OH + 3 O2
Direct To Ethanol® technology
Direct To Ethanol® Commercial Vision
• Over-expression of genes for intracellular
fermentation pathway enzymes in the
cyanobacteria
• Enhanced cyanobacteria consume
• CO2
• Saltwater
• Sunlight
in low cost photobioreactors, to
photosynthetically produce high amounts of
ethanol and biomass
• Biomass is converted into various oils and
ethanol is purified to fuel grade purity
• Main capital cost drivers
• VIPERTM film photobioreactors
• Downstream purification
• Main operating cost drivers
• CO2
• Energy use (downstream operations)
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CO2 Sourcing – Important Considerations
• Potential ‘Anthropogenic’ Sources
• Power plants
• Natural gas processing plants
• Fertilizer plants
• Hydrogen plants (Steam Methane Reformers)
• Fermentation plants
• Cement plants
• Requirements for CO2 source
• Size
‒ A 15 mgal EtOH/yr Algenol facility will need over 100,000 tonne CO2/yr
• Location
‒ Important for transporting CO2 to bio-refinery and product to market
• Cost of CO2 capture
‒ Depends on the quality of feed gas – including CO2 concentration
‒ Desired – more CO2 and less unwanted (toxic) impurities
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Power Plants – the Biggest CO2 Source
• “The burning of coal, natural gas and oil for electricity and heat is the largest
single source of global greenhouse gas emissions”
United States Environmental Protection Agency1
• The largest coal fired power plant (3.5 GW) in the nation generates enough
CO2 to support over 1 Bgal EtOH/yr (via Direct to Ethanol)2
• US total power from coal in 2006 was
227.1 GW, can support over
90 Bgal EtOH/yr (photobioreactors laid
over half the state of Maine). Corn EtOH
would need half of Alaska!
• Coal and natural gas contribute 67% to
the electricity generated in US
1USEPA, http://www.epa.gov/climatechange/ghgemissions/global.html 2http://ghgdata.epa.gov/ghgp/main.do#/facilityDetail/?q=&st=GA&fc=13015&fid=1001505&sf=11001000&lowE=0&highE=2300
0000&g1
Fuel Mix for U.S. Electricity
Generation, EIA, year 2011 data
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Carbon Capture from Power Plants
• Coal plants in general are more polluting than natural gas
• SOx emission – 2591 lb/109 BTU (coal), ~1 lb/109 BTU (natural gas)
• CO2 emission1 – 940 kg/MWe (coal), 367 kg/MWe (natural gas)
• Rise of low-cost non-traditional natural gas
• Power plants have been/will be switching to natural gas for both
economic and environmental reasons
• Three main types of capture technologies exist
• Post-combustion
• Pre-combustion
• Oxy-fuel combustion
• For existing coal and natural gas fired plants, post-combustion
capture is readily applicable due to the relative ease of retrofits
1Rubin, E. S. et al., International Conference on Greenhouse Gas Control Technol., Vol. 1, 2004
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Effect of CO2 Price on Direct to Ethanol®
• A CO2 capture cost of $50/tonne1 will result in total operating expenses of $1.40/gal
of ethanol.
• Algenol is currently targeting an operating cost of $1.20/gal, though our overall goal
is below $1.00/gal.
• Achieving a CO2 delivery cost of $35/tonne enables Algenol to reach $1.20/gal in
operating expenses with $0.27/gal as the CO2 cost.
• CO2 from steam methane reformers can be delivered at approximately $35-$45 per
tonne. Fermentation and Ammonia plants can be even cheaper.
• Techno-economic analyses on CO2 capture stations reported in the literature include
the cost of CO2 compression and transportation for CCS purposes ($7-$10/tonne).
Algenol does not need that if co-located.
• Based on these considerations, in the analysis to follow, we assume $35/tonne for
CO2 delivered to the system boundary at modest pressure.
1 Zhai, H. and Rubin, E.S., “Comparative Performance and Cost Assessments of Coal- and Natural-Gas-Fired Power Plants under
a CO2 Emission Performance Standard Regulation”, Energy & Fuels, In press, doi: 10.1021/ef302018v (2013).
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Natural Gas Power Plant - Algenol Integration
• A simple carbon footprint analysis is performed on a coupled power/ethanol
production facility
• Analysis considers the parasitic load of typical liquid amine capture systems
on natural gas power stations
• CO2 assumed to be consumed within the Algenol Direct to Ethanol®
biorefinery
• The full life cycle analysis on this element of the system, with CO2 supplied at
the system boundary, has been reported previously1
• The produced ethanol is burned as a liquid fuel
• Fossil fuel is displaced by ethanol use
1Luo, D., et al., . “Life cycle energy and greenhouse gas emissions for an ethanol production process based on blue-green
algae”, Environmental science & technology, 44(22), pp. 8670-8677, (2010)
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Capture vs. Utilization
• Carbon Footprint: Direct To Ethanol® advantaged vs. CCS and greatly advantaged vs. Status Quo
• Same conclusion for Coal-Fired Power Plant (total Parasitic Load for CCS of typically 30%)
NG Power Plant (217.4 MW)
CO2 Capture (1 atm)
Algenol Ethanol Production
Ethanol Combustion
280 MW-eq.
Fuel Energy
200 MW
Electricity
105.8 TCO2/h emissions for Algenol Case
NG NG
(supply chain)
Luo et al
(LCA, 1% condensate, VCD case)
79.7
TCO2/h
15.3 TCO2/h 71.7 TCO2/h 10.8 TCO2/h
non-combustion
Algenol Plus NG Power Plant
200 MW Electricity CO2 Sequestration (Total: 226.4 MW)
Gasoline Combustion
Additional Compression
Parasitic Load – 4%
111.0 TCO2/h For Sequestration Case
280 MW-eq. Fuel
Energy
174.8 TCO2/h For No CO2 Capture Case
200 MW Electricity Gasoline Combustion
280 MW-eq. Fuel
Energy
Comparison to Sequestration (CCS) Comparison to Status Quo (No Capture)
Power Plant
Parasitic Load
- 8%
8.0 TCO2/h
not captured
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Algenol vs. Other Transportation Fuels
• It is important to see how Algenol’s ethanol shares the stage with
other transportation fuels –
• Gasoline
• Diesel
• Corn ethanol
• Grid electricity (plug-in electric vehicle)
• Parameters for comparison –
• Cost of producing one unit of energy
• Carbon footprint in producing one unit of energy
• The production costs are computed by subtracting sales tax,
distribution cost, and marketing cost from the retail price
• The carbon footprint is calculated via Argonne National Laboratory’s
GREET model (except Algenol ethanol)
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Cost and Carbon Footprint on an Energy-to- Wheel Basis 1
• When reduced to price per
MJ to vehicle wheel, electric
vehicles (EVs) are lowest
cost (neglects infrastructure
and CAPEX associated with
electrical fleet)
• Driving a vehicle with
electricity generated from a
power plant (US average
grid) produces a carbon
footprint much larger than
Direct to Ethanol ®
Direct To Ethanol ® strongly
advantaged when carbon footprint is
considered
1Lively, Sharma, McCool, Chance, “CO2 as a feedstock for cyanobacteria-based biofuels: cost of recovery and wells-to-wheels
analysis”, to appear in Chemical Engineering Progress
0
50
100
150
200
250
300
350
400
Gasoline Diesel CornEthanol
AlgenolEthanol
GridElectricity
g-C
O2
/MJ
(ve
hic
le)
0
2
4
6
8
10
12
14
16
₵/M
J (v
eh
icle
)
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Conclusions and Path Ahead
• The CO2 capture and utilization analyses show that carbon capture from both natural
gas and coal fired power plants is economically feasible in providing the CO2
feedstock for a biofuel production process.
• Our carbon footprint analysis indicates –
• Corn ethanol: Algenol’s ethanol is less expensive with a much lower carbon footprint
when compared to corn ethanol. And, no food vs. fuel issue.
• Gasoline and Diesel: Algenol compares favorably in cost to petroleum derived gasoline
and diesel, but with a much lower carbon footprint.
• Grid electricity (w/o CCS): Compared to electric vehicles, Algenol has a slightly higher
cost, but is greatly advantaged in carbon footprint when there is no CCS for electricity
generation.
• Grid electricity (w/ CCS): The carbon footprint of the Direct-to–Ethanol® compares
favorably and the CO2 is re-utilized versus sequestered underground where it creates
many potential regulatory, safety and environmental issues that are still not well
understood.
• Algenol is actively developing its Direct to Ethanol technology at its integrated
biorefinery in Florida with a plan to produce > 10,000 gal liquid fuels/acre-yr