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Algal Biofuels Can Make a Difference

Renewable Energy Roundtable

Philip T. Pienkos

March 27, 2012 NREL/PR-7A40-54590

2

What is Lignocellulosic Biomass?

38-50%

5-13%

23-32% 15-25%

Lignin

Other Cellulose (Glucose sugar)

Hemicellulose (Pentose sugars)

(“Young clean coal”) Softwoods

Grasses

Hardwoods

Crop residues

MSW

(Extractives, ash, etc.)

3

Primary Conversion Routes

Transformation through Intermediates (sugars)

Biochemical Conversion

Thermochemical Conversion

Gasification (reduction to CO, H2) and Pyrolysis

Initial focus on ethanol and mixed alcohols. Now attention turning to

advanced hydroccarbon biofuels

Photo by David Parsons, NREL/PIX 06809

4

Terrestrial Biomass Is Not Enough

• Potential sustainable biomass production: 1.3B tons per year o Ag wastes o Municipal solid wastes o Forestry wastes o Energy Crops

• Convert to 130B gallons ethanol = 87B GGE

Source: http://www1.eere.energy.gov/biomass/pdfs/final_billionton_vision_report2.pdf

5

U.S. Transportation Fuel Demand

2010 2035 Gasoline 126 116 Diesel 43 64

Jet fuel 23 27

Source: http://www1.eere.energy.gov/biomass/pdfs/final_billionton_vision_report2.pdf

Products in a Barrel of Crude (gal)

Gasoline* (Finished Motor Gasoline – E10) (cars & trucks)

Diesel (on-road, rail)

Aviation (jet fuel)

23 bgy

126 bgy

43 bgy

* Peaked in 2004 at 136 bgy

6

U.S. Transportation Fuel Demand

2010 2035 Gasoline 126 116 Diesel 43 64

Jet fuel 23 27

Source: http://www1.eere.energy.gov/biomass/pdfs/final_billionton_vision_report2.pdf

Products in a Barrel of Crude (gal)

Gasoline* (Finished Motor Gasoline – E10) (cars & trucks)

Diesel (on-road, rail)

Aviation (jet fuel)

23 bgy

126 bgy

43 bgy

* Peaked in 2004 at 136 bgy

One billion tons is not enough. Ethanol only addresses the gasoline

fraction.

7

Multiple Paths to Energy Security

• Domestic coal and natural gas reserves can be converted to liquid fuels

• Supplement biomass to provide path to energy security

• Environmental impact o Greenhouse gas emissions o Water usage and

contamination o Land usage

Photo by David Parsons, NREL/PIX 06734

Photo by David Parsons, NREL/PIX 05048

8

What Can Algae Contribute?

• Wigmosta et al. evaluated available US lands appropriate for algal cultivation o 166,000 square miles o 57B gallons oil per year

• Based on conservative productivity estimates o 600 gallons/acre/year o Mascarelli (2009): 1400

gallons/acre/year o Weyer et al. (2010): 3800-5500

gallons/acre year • Job creation

o Total workers: 37,498 o Acres per worker: 144 o Typical farm acres per worker:

100-200

Wigmosta, M. S., A. M. Coleman, R. J. Skaggs, M. H. Huesemann, and L. J. Lane (2011), National microalgae biofuel production potential and resource demand, Water Resour. Res., 47, W00H04, doi:10.1029/2010WR009966. Figure courtesy Mark Wigmosta, PNNL

9

How Algal Biofuels Figure Into Renewable Fuel Standards

5 billion gallons could come from algae

10

Why Fuels from Algae?

• Algae can produce more lipids per acre than terrestrial plants -- potentially 10x - 100x

• Can use marginal, non-arable land • Can use saline/brackish water • No competition with food, feed, or

fiber • Can utilize large waste CO2

resources • Potential to displace significant

amount of U.S. diesel and jet fuel usage

• An algal biorefinery could produce oils, protein, and carbohydrates and a variety of other products

Photo by Dennis Schroeder, NREL/PIX 18070

Photo by Warren Gretz, NREL/PIX 01723

11

Input/Output

• Wigmosta et al. evaluated available US lands appropriate for algal cultivation o 166,000 square miles o 57B gallons oil per year o Human Resources

– Total workers: 37,498 – Acres per worker: 144 – Typical farm acres per worker:

100-200 o Evaporative losses of 8 x

1,013 gallons water per year o 1,400 gallon water per gallon

fuel

Wigmosta, M. S., A. M. Coleman, R. J. Skaggs, M. H. Huesemann, and L. J. Lane (2011), National microalgae biofuel production potential and resource demand, Water Resour. Res., 47, W00H04, doi:10.1029/2010WR009966. Figure courtesy Mark Wigmosta, PNNL

12

Bio-based Products from Algae

TAGs

HC Fuels

Fatty Acids TAGs

Algae Cyanobacteria Photosynthetic Bacteria

Commodity Chemicals (Ethylene)

Specialty Chemicals

(Carotenoids)

Image Removed

for Publication

Image Removed for Publication

Image Removed for Publication

Photo by Dartmouth Electron Microscope Facility, Dartmouth College, NREL/PIX 19459

Photo by Toshi Otsuki, NREL/PIX 08332

Image Removed

for Publication

13

Comparing Potential Oil Yields

Crop Oil Yield

Gallons/acre Corn 18 Cotton 35 Soybean 48 Mustard seed 61 Sunflower 102 Rapeseed/Canola 127 Jatropha 202 Oil palm 635

Algae (Wigmosta et al.) 600

Algae (Mascarelli) 1,400

Algae (Weyer et al.) 3,800-5,500

Photos by Oak Ridge National Lab, John De La Rosa, Warren Gretz, NREL/PIX 19965, 01768, 03016, 04078

14

Land Usage: A Matter of Scale

Photos by Warren Gretz, Dennis Schroeder, Bob Allan, NREL/PIX 03246, 10512, 19549

15

Land Usage: A Matter of Scale

Corn 144,000 square miles

Energy crops

86,000 square miles

Photos by Warren Gretz, Dennis Schroeder, Bob Allan, NREL/PIX 03246, 10512, 19549

Algae 166,000 square miles

16

What Is the Definition of Marginal Land?

Southwest Desert

Image Removed for Publication

Image Removed for Publication

Image Removed for Publication

Image Removed for Publication

Southeast Coast

Untilled Farmland

Freeport, TX

Ft. Myers, FL

Photos by Warren Gretz, NREL/PIX 08026

17

Land Usage: Competition

Image Removed for Publication

Image Removed for Publication

18

Design Configuration

Green = algae cell density

Lipid Extraction

Phase Separation

Solvent Distillation

Upgrading (hydrotreater)

Anaerobic Digestion

Algae Growth

CO2

Makeup nutrients

Recycle nutrients/ water

Makeup solvent Solvent recycle

Spent algae + water

Sludge

Biogas for

energy Flue gas from turbine

Hydrogen Offgas

Naphtha

Diesel

Raw oil

Power

Flocculent

Recycle water Blowdown

Makeup water

Centrifuge DAF Settling

0.05% (OP) 0.4% (PBR)

1% 10% 20%

Steam turbine combined cycle

10%

5%

Red = harvesting/extraction losses

10%

19

Results: Baseline Costs

$523

Direct Installed Capital, $MM (PBR) PBR System

CO2 Delivery

Harvesting

Extraction

Digestion

Power Generation

Inoculum System

Hydrotreating

OSBL Equipment

Land Costs

$114

Total = $243MM

Total = $637MM

Baselines show high costs of today’s currently available technologies, opportunities for cost reduction

$9.28

$17.52

$10.66

$19.89

$0

$5

$10

$15

$20

$25

OP(TAG)

PBR(TAG)

OP(Diesel)

PBR(Diesel)

Prod

uct s

ellin

g pr

ice

($/g

al)

TAG/Diesel Selling Prices (OP vs PBR)

Operating ($/gal of product) Capital ($/gal of product)

$67

$12

$46 $18

$12

$13

$24

$9

$21

$22

Direct Installed Capital, $MM (Ponds)

Ponds

CO2 Delivery

Harvesting

Extraction

Digestion

Power Generation

Inoculum System

Hydrotreating

OSBL Equipment

Land Costs

20

Sensitivity: Ponds

-$6 -$4 -$2 $0 $2 $4 $6 $8

Evaporation rate (0.15 : 0.3 : 0.6 cm/day)

Water source (underground : utility purchase)

Water recycle (100% : 95% : 80%)

CO2 price ($0 : $36 : $70/ton)

Inoculum costs (50% : base : 150%)

Extraction costs (50% : base : 150%)

Nutrient recycle (100% : base : 0%)

Harvesting costs (50% : base : 150%)

Pond liner (none : add liner)

Operating factor (365 : 330 : 250 days/yr)

Growth rate (50 : 25 : 12.5 g/m2/day)

Lipid content (50 : 25 : 12.5%)

Change to TAG price ($/gal)

Open Pond Sensitivities

More “bang for the buck” targeting lipids vs growth rate (Realistically, difficult to maximize both simultaneously)

21

Projecting future costs

Growth rate 25 g/m2/d 25 g/m2/d 30 g/m2/d 30 g/m2/d 1.25 g/L/d 1.25 g/L/d 1.5 g/L/d 1.5 g/L/d

Lipid content 25% 40% 50% 50% 25% 40% 50% 50%

Harvesting cost Base Cut by 50% Cut by 50% Cut by 50% Base Cut by 50% Cut by 50% Cut by 50%

Extraction cost Base Base Cut by 50% Cut by 50% Base Base Cut by 50% Cut by 50%

Spent biomass utilization

AD AD AD Sell @ $500/ton

AD AD AD Sell @ $500/ton

$9.28

$5.45

$3.99

$2.27

$17.52

$11.19

$7.74

$6.10

$0

$2

$4

$6

$8

$10

$12

$14

$16

$18

$20

OP(base)

OP(target 1)

OP(target 2)

OP(high-valuecoproduct)

PBR(base)

PBR(target 1)

PBR(target 2)

PBR(high-valuecoproduct)

Prod

uct s

ellin

g pr

ice

($/g

al)

Capital ($/gal of lipid) Operating ($/gal of lipid)

22

Establishing cost targets (MYPP)

$0

$2

$4

$6

$8

$10

$12

2012 2014 2016 2018 2020 2022 2022* 2022**

Prod

uct s

ellin

g pr

ice

($/g

al)

Open Pond Learning Curve

Operating ($/gal of lipid)

Capital ($/gal of lipid)

Raw oil price (total)

Diesel price (total)

*Cut extraction costs by 50% **Cut extraction costs by 50% and sell spent biomass @ $500/ton

Cut harvesting cost 50%

Growth rate [g/m2/day]

25 20 20 25 30 30 30 30

Lipid content [dry wt%]

25% 35% 40% 40% 40% 50% 50% 50%

23

Comparison to Biochemical Ethanol Cost Curve

$0.00

$1.00

$2.00

$3.00

$4.00

$5.00

$6.00

$7.00

$8.00

$9.00

$10.00

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

Min

imum

Eth

anol

Sel

ling

Pric

e (2

007$

per

gal

lon)

Conversion Feedstock

$3.85 $3.64 $3.57

$3.18 $2.77

$2.62 $2.15

$4.27

$5.33

$6.90

$9.16

24

Multiple Biomechanical Conversion Strategies and Routes of Algal Feedstocks Into Bio Fuels

Ethanol and butanol from extracted algal biomass could add

an additional 24 B GGE. Total contribution of algal biomass could be as high as 90 B GGE.

25

Algal Biofuels Can Reshape the Food vs. Fuel Debate

• Algal biomass used as food supplement since pre-columbian times

• Extracted biomass could provide approximately 180M tons protein per year o Aquaculture o Animal feed o Pet food o Human food

• Indirect land usage very different for algae compared to terrestrial crops

• Possible competition for fertilizer inputs especially potassium o Recycle option for some processes o Capture nutrients from wastewater or

natural blooms

Photos by Roger Taylor NREL/PIX 07491

26

Algae and Carbon Capture

• Algal biomass sufficient to produce 57B gallons oil per year would require approximately 1B tons CO2

• This is equivalent to output from 350 500 MW coal-fired power plants or 70% of US capacity

• A 500 MW power plant would require approximately 200 square miles of algae ponds to capture CO2

• Capture occurs only in daylight hours • Transportation/distribution will add to capital

costs • CO2 pipelines carry fossil CO2

o Collected, transported and re-injected for enhanced oil recover

o Use for algae cultivation will add to greenhouse gases

• Concentrated forms of CO2 (cement kilns, fermentation offgas, anaerobic digester) better scaled and more economical for transport

• Air capture CO2 could be game changer

27

Conclusions

• Even by conservative calculations, algal biomass could surpass terrestrial biomass for contribution to liquid fuel replacements

• Land requirement would be significant (~5% of conterminous US area) o Competition for other uses o Indirect land use mitigated by complexity of shift from

agriculture to algae culture o brine disposal could greatly reduce reliance on freshwater

• Algae could mitigate significant CO2 emissions, but it will be difficult to balance local supplies and demand

• Algae could add to global food supply rather than take away o Issues of scale and quality must be considered