NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

Biochemical Refining of Lignocellulose 

to Biofuels: Status and Prospects

AIChE Annual Meeting, 

Salt Lake City, Utah

Sustainable Biorefineries

Plenary, Paper 431b

James D. McMillan

jim.mcmillan@nrel.gov

November 10, 2010

NREL/PR-5100-51132
Innovation for Our Energy Future

Outline

Current Situation

– Biofuels progress and drivers

– New initiatives

– RDD&D situation

NREL R&D Progress

– Biochemical cellulosic ethanol

– Improved piloting facilities

– R&D beyond cellulosic ethanol

• National Advanced Biofuels Consortium (NABC)

Outlook and Final Thoughts

– On-going challenges and unresolved issues

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Innovation for Our Energy Future

Recent History of Advanced Biofuels

3

• 1995-2000: Demonstrate technical feasibility

Focus on cellulosic ethanol

• 2000-2005: Show economic feasibility & scale potential

Focus remains largely on cellulosic ethanol

• 2005-2010: Increase funding to accelerate biofuels RDD&D

Expand product portfolio to encompass higher 

alcohols and hydrocarbons, begin funding new 

concepts including hybrid BC/TC and algal 

pathways
Innovation for Our Energy Future

Current Situation

4

Advanced biofuels R&D booming

– Many potential routes being 

rigorously studied (BC, TC, hybrid, 

algae, etc.)

– Major bioenergy research centers 

formed, actively engaged (BESC, 

JBEI, GLBRC, EBI, etc.)

– R&D community 100x bigger (more 

than 50 sessions at this meeting!)

Commercialization starting

– Many dozens of companies pursuing 

technology development

– Cellulosic and algal biofuels 

production occurring, albeit at a 

pace much slower than planned or 

initially forecasted

Danish fueling station pump dispensing

E5 gasoline-ethanol blend containing

wheat straw-derived cellulosic ethanol

photo courtesy of Claus Felby (U. Copenhagen)
Innovation for Our Energy Future

Drivers for Advanced Biofuels Remain Strong

Biomass is a sustainable, near-term opportunity to reduce 

U.S. reliance on fossil fuels.

Science and Discovery

Climate Change

Economic Prosperity

Clean, Secure Energy

“Developing the next generation of biofuels is key to our effort to end 

our dependence on foreign oil and address the climate crisis – while 

creating millions of new jobs that can't be outsourced. With American 

investment and ingenuity – and resources grown right here at home –

we can lead the way toward a new green energy economy.” 

– Secretary of Energy Steven Chu

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Innovation for Our Energy Future

Source: Energy Information Administration, “Petroleum Explained” and AEO2009, Updated (post-ARRA), Reference Case.

More Fuels Needed to Displace Fossil Oil

• Advanced biofuels and 

products are needed to 

displace the entire barrel 

(14.7 mbd = 225 bgy = 70% of U.S. 

petroleum use)

< Heavy duty/diesel and jet fuel 

substitutes required to displace 

several components 

(43 bgy diesel + 25 bgy aviation fuel + 

10 bgy fuel oil for shipping = 

78 bgy = 36% of transportation fuel)

< Cellulosic ethanol displaces 

light duty gasoline fraction 

(140 bgy = 64% of transportation fuel)

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Innovation for Our Energy Future

DOE Stimulating Progress Across Supply Chain

The USDOE Biomass Program is working to advance biomass 

technologies in support of its mission to strengthen America’s energy 

security, environmental quality, and economic vitality through:

Feedstocks

Improving 

conversion 

efficiencies and 

costs

Evaluating 

vehicle 

emissions, 

performance, 

and 

deployment 

options

Providing a 

clean, 

domestic, 

dispatchable

renewable 

source of power

Expanding 

portfolio 

beyond 

cellulosic 

ethanol to 

hydrocarbon 

fuels 

Developing 

lower cost 

feedstock 

logistics 

systems

Conversion 

technologies

Systematically 

validating and 

deploying 

technology at 

first-of-a-kind 

facilities

Infrastructure Biopower Advanced 

biofuels 

Integrated 

biorefineries

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Innovation for Our Energy Future

Integrated Biorefinery Conversion Platforms

8

Thermochemical 

Platform

Sugar Platform

Biomass

Combined 

Heat & 

Power

Residues

Clean Gas

Conditioned Gas

or Bio-oils

Sugar Feedstocks

Advanced Biomass R&D

Systems Integration

Fuels, 

Chemicals, 

& Materials

Integrated 

Industrial 

Biorefineries
Innovation for Our Energy Future

Biomass Conversion to Fuels

Product

Recovery/

Purification

Hydrolysate

Conditioning/

Detoxification

Pretreatment

& Enzymatic

Hydrolysis/

Saccharification

Feedstock

Prep &

Handling

Biomass

Sugar

Fermentation

9

Major Biochemical Conversion Steps

Product

Recovery/

Purification

Syngas

Cleanup &

Conditioning/

Tar Reforming

Thermochemical

Synthesis Gas

Production/

Gasification

Feedstock

Prep &

Handling

Syngas

Catalytic

Upgrading/

Product

Synthesis

Major Thermochemical Conversion Steps
Innovation for Our Energy Future

Biomass Conversion to Fuels 

Hybrid Approaches

Product

Recovery/

Purification

Syngas

Cleanup &

Conditioning/

Tar Reforming

Thermochemical

Synthesis Gas

Production/

Gasification

Feedstock

Prep &

Handling

Syngas

Catalytic

Upgrading/

Product

Synthesis

Hydrolysate

Conditioning/

Detoxification

Pretreatment

& Enzymatic

Hydrolysis/

Saccharification

Biomass

Sugar

Fermentation

Syngas Fermentation

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Innovation for Our Energy Future

Biomass Conversion to Fuels 

Hybrid Approaches

Product

Recovery/

Purification

Syngas

Cleanup &

Conditioning/

Tar Reforming

Thermochemical

Synthesis Gas

Production/

Gasification

Feedstock

Prep &

Handling

Syngas

Catalytic

Upgrading/

Product

Synthesis

Hydrolysate

Conditioning/

Detoxification

Pretreatment

& Enzymatic

Hydrolysis/

Saccharification

Biomass

Sugar

Fermentation

Aqueous

Phase

Reforming

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Innovation for Our Energy Future

Integrated Biorefinery Projects

Scale Description Feedstocks Fuel/Product

R&D

2 projects

Includes R&D and a 

preliminary engineering 

design 

Poultry Fat, Woody 

Biomass, Ag Residue, 

Algal Oil

Renewable Fuels, 

Renewable Gasoline, 

Renewable Diesel

Pilot Scale

12 projects

Process a minimum of 1 

dry ton per day biomass 

and verify integrated 

performance of the given 

suite of technologies from 

both a technical and an 

economic perspective for 

the first time 

Algae, CO2, Woody 

Biomass, Sweet 

Sorghum, Corn Stover, 

Switchgrass, Energy 

Sorghum, Ag and 

Forestry Residue, 

Hybrid Poplar

Ethanol, Cellulosic 

Ethanol, Renewable 

Diesel, Jet Fuel, 

Renewable Diesel

Demonstration 

Scale

9 projects

Validate process 

technology performance 

from both technical and an 

economic perspectives 

at a scale predictive of a 

commercial facility

Wheat Straw, Corn 

Stover, Poplar 

Residues, Woody 

Biomass, Algae, Mill 

Residues, MSW, Ag and 

Forestry Residue

Cellulosic Ethanol, 

Renewable Sulfur-free 

Diesel Fuel, Renewable 

Hydrocarbon-based 

Fuel, Renewable 

Gasoline, Renewable 

Diesel, Jet Fuel, 

Succinic Acid

Commercial 

Scale

6 projects

Process a minimum of 700 

dry tons per day biomass 

in a a first-of-a-kind or 

“beta” commercial facility

Lignocellulosic

Biomass, Corn Cobs, 

Woody Biomass, Mill 

Waste, Sorted MSW

Cellulosic Ethanol, 

Ethanol, Methanol

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Innovation for Our Energy Future

For more information visit: 

http://www.eere.energy.gov/biomass/integrated_biorefineries.htm

DOE’s Integrated Biorefinery Project Map

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Innovation for Our Energy Future

Feedstock Conversion Intermediate Conversion Product Performer 

Agricultural 

Residues

biochemical

gasification

pyrolysis oil

syngas

sugar

catalysis

fermentation ethanol

diesel

Abengoa, Poet,

Verenium, ADM

Ineos

REII

Forest 

Resources

biochemical

gasification

pyrolysis oil

syngas

sugar

catalysis

fermentation

ethanol

gasoline

diesel

jet fuel

Lignol, Mascoma, 

Pacific Ethanol

RSA, API, Zeachem,

Blue Fire

Range Fuels

Haldor Topsoe

Clear Fuels 

New Page, 

Flambeau 

Energy 

Crops / 

Grasses/

biochemical

sugar fermentation

ethanol

diesel

ICM, Logos

Amyris

GTI, UOP

succinic acid Myriant

Integrated Biorefinery Projects, cont’d.

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Innovation for Our Energy Future

NREL R&D Highlights

Biochemical Cellulosic Ethanol Progressing

New Facilities Coming On-line (TCPDU and IBRF)

New Initiatives Underway (BESC and NABC)

15
Achieving Economic Feasibility

Process cost drivers

 Yield > Conc > Rate

– Feedstock

– Capital equipment

• Pretreatment

• Enzyme Production

• Distillation

• Boiler/CHP

– Operating cost

– Coproduct value

 Reduce CAPEX through 

co-location and process 

intensification

$0.90 

$0.57 

$0.53 

$0.43 

$0.50 

$0.26 

$0.33 

$0.12 

$0.35 

$0.12 

$-

$0.50 

$1.00 

$1.50 

$2.00 

$2.50 

$3.00 

2008 SOT 2012 Target

Cellulase

Enzymatic Hyd. 

& Ferm.

Pretreat & 

Condition

Non-conversion 

(incl. utilities)

Feedstock

16

16 Innovation for Our Energy Future
Economic Sugar Production Remains 

Biggest Challenge

Enzymatic

cellulose

hydrolysis

Pre-processing

Lignocellulose 

Feedstock Collection 

and Delivery

Pretreatment /

Prehydrolysis

(make accessible

to enzymes)

Conditioning

Beer Slurry to 

Biofuel 

(Ethanol or 

Another Fuel) 

and Solids 

Recovery

Biomass

sugar

fermentation

Cellulases

Hemicellulases Hexose/Pentose 

Utilizing Microbe

Pretreatment and Enzymatic Hydrolysis = 

Sugar Production (Saccharification)

•17

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Innovation for Our Energy Future

Increasing Monomeric Xylose Yields

18

50

60

70

80

90

100

Primary 

Pretreatment

Thermo./ Enz. 

Oligomer 

Conversion

Enzymatic 

Xylan 

Conversion

Overall 

Process Yield

% of Original Xylan

% as Xylose 

Monomers

% as 

Soluble 

Oligomers

% as 

Insoluble 

Xylan

% as 

Furfural

Source: Rick Elander (NREL)

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Innovation for Our Energy Future

Intensifying Enzymatic Hydrolysis

19

Substrate: Dilute acid pretreated corn stover

Enzyme loading: 40 mg cellulase/g cellulose

Source: Dan Schell (NREL)
Innovation for Our Energy Future

$0.00 

$1.00 

$2.00 

$3.00 

$4.00 

$5.00 

$6.00 

$7.00 

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

Conversion Feedstock $6.47 

$2.85 

$2.69 $2.61 

$2.40 

$1.92 

$1.68 $1.49 

$6.47 

$2.85 

$2.69 $2.61 

$2.40 

$1.92 

$1.68 $1.49 

$6.47 

$2.85 

$2.69 $2.61 

$2.40 

$1.92 

$1.68 $1.49 

$6.47 

$2.85 

$2.69 $2.61 

$2.40 

$1.92 

$1.68 $1.49 

12/4/09

Biochemical Technology Progress (2007$)

Improve Enzymes

Scale Up Pretreatment

Scale Up Bioprocessing

20

Source: Humbird and Aden. 2009. NREL/TP-510-46214. Minimum Ethanol Selling Price ($)
Innovation for Our Energy Future

Integrated Biorefinery Research 

Facility(IBRF)

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Innovation for Our Energy Future

State of the art cellulosic biofuels piloting facility

Two (2) parallel processing trains for pretreatment and 

primary enzymatic liquefaction

Accelerate cost reduction focused R&D for 2012 and 

beyond

Provide multiple biomass pretreatment/feedstock 

options for RD&D support (unparalleled flexibility)

Greatly improve industry partnering capabilities to 

speed scale up and commercial deployment

DOE’S prime facility for future pilot scale pretreatment 

and enzymatic saccharification R&D

Early March 2010

NREL’s (DOE’s) Expanded Pilot Plant (IBRF)

22
Innovation for Our Energy Future

Integrated Biorefinery Research Facility

23

June 2010
Innovation for Our Energy Future

Inside View of IBRF Operations Level

24
Innovation for Our Energy Future

National Advanced Biofuels Consortium

(NABC)

25
Project Objective – Develop cost-effective technologies to 

supplement petroleum-derived fuels with sustainable advanced 

“drop-in” biofuels compatible with today’s transportation 

infrastructure.

ARRA Funded: - 3 year effort 

- DOE Funding $35.0M 

- Cost Share $15.1M 

Consortium Leads Total $50.1M

National Renewable Energy Laboratory

Pacific Northwest National Laboratory

Consortium Partners

Albemarle Corporation

Amyris Biotechnologies

Argonne National Laboratory

BP Products North America Inc.

Catchlight Energy, LLC

Colorado School of Mines

Iowa State University

Los Alamos National Laboratory

Pall Corporation

RTI International

Tesoro Companies Inc.

University of California, Davis

UOP, LLC

Virent Energy Systems

Washington State University

National Advanced Biofuels Consortium

NABC: For Open Distribution 26
Infrastructure Compatibility Strategy

NABC: For Open Distribution 27
Innovation for Our Energy Future

Outlook and Final Thoughts

28
Innovation for Our Energy Future

Outlook for 2011-2015

29

• 1990-2000: Demonstrate technical feasibility

Focus on cellulosic ethanol

• 2001-2005: Show economic feasibility & scale potential

Focus remains largely on cellulosic ethanol

• 2006-2010: Increase funding to accelerate biofuels RDD&D

Expand RDD&D portfolio to higher alcohols and 

hydrocarbons, begin funding new concepts 

including hybrid BC/TC and algal pathways

• 2011-2015: Prove out & winnow advanced biofuels options

Bring first large scale demonstrations on line
Innovation for Our Energy Future

Leverage Past Learnings to Succeed in 

Commercialization Efforts

Key to success at scale is accurately estimating 

cost and performance at smaller scales!

Plant cost growth strongly correlated with: – Process understanding (integration issues)

– Project definition (estimate inclusiveness)

Plant performance strongly correlated with:

– Number of new steps

– % of heat and mass balances based on data

– Waste handling difficulties

– Plant processes primarily solid feedstock

 These issues all apply to lignocellulose processing 

using new technologies. We must directly tackle them!

Rand. 1981. Understanding Cost Growth and Performance Shortfalls in Pioneer Process Plants.

30 30
Innovation for Our Energy Future

Energy Density vs. Mass and Enthalpy Yield

31

Theoretical yield calculations from: Rude and Schirmer. 2009. Current Opinions in Microbiology, 12:274-281.

Ethanol

Butanol

Ethyl hexadecanoate

Farnesene

Squalene Pentadecane

3-Methyl-1-butanol

Squalene

Isobutanol

Hentriacontene

Farnesene
Innovation for Our Energy Future

Anabolic vs. Catabolic Product Pathways

32

Source: Fortman et al.

2008. Trends in Biotech. 

26(7): 375-381

Isoprenoid

Pathway

Fatty Acid

Synthesis

TCA

(Krebs)

Cycle

Glycolytic

Pathway

Pentose

Phosphate

Pathway
Innovation for Our Energy Future

Final Thoughts

Lots of progress happening. Many process and product 

options being advanced and scaled up to pilot and 

demonstration scales. Commercialization beginning.

Solids handling issues and compositional analysis 

throughput are still challenging technical issues that 

hinder the pace of biomass to biofuels RDD&D

Factors in play for cellulosic biofuels include:

• What pretreatment and enzymatic hydrolysis 

(saccharification) schemes will prove out?

• How much and how quickly will hydrolytic enzymes and 

biofuels production strains be improved?

• How quickly will higher alcohols and hydrocarbons be 

proven at scale?

Potential game changers include:

• Price on (net) carbon, GHG emissions mitigation

• Competition for feedstocks (biopower, bioproducts)

• Production of higher value coproducts

• Price of petroleum & ethanol blend limit for non-FFVs

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Innovation for Our Energy Future

• USDOE’s EERE’s Office of the Biomass Program – Funding and selected 

slides on USDOE’s strategy and investments

•NREL’s Rick Elander, Steve Decker, Erik Kuhn, Nick Nagle and Joe Shekiro

– Data on xylan to xylose yield improvement

•NREL’s Dan Schell, Alex Chapeaux, Nancy Dowe Farmer and Andrew Lowell 

– Data on enzymatic hydrolysis glucose yields = f[insoluble solids]

Acknowledgments

34
Innovation for Our Energy Future

Thanks for Your Attention!

Questions?

35
Innovation for Our Energy Future

More Information

National Renewable Energy Laboratory

www.nrel.gov

DOE’s Biomass Program

www.eere.energy.gov/biomass/

DOE-USDA Biomass R&D Initiative

www.brdisolutions.com

Alternative Fuels

www.afdc.doe.gov

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