Sustainable Bioenergy Production: Opportunities and Challenges

Samir K. Khanal, Ph.D., P.E.

Associate Professor of Bioengineering Department of Molecular Biosciences and Bioengineering

University of Hawai’i at Mānoa

April 3, 2014

Universidad de Santander, Cucuta, Colombia

Portalegre, Portugal (May 2013)

My hobbies/interests

Partnership/Collaboration:

• Industries, other national/international universities and national labs

Protein-rich biomass production: • Protein for animal feed • Nitrogen for organic farming

Anaerobic digestion research: • Energy crops, agri-residues • Animal manure/food wastes and Industrial wastewater

Bioenergy &

Environment Research

Group

Aquaponics:

• Nitrogen transformation and climate change

Bioenergy and biobased products from energy crops: • Green processing • Advanced biofuels

STEM:

• Hands-on training for teachers • Lab experience for middle/high school students

Managing graduate program:

• Bioengineering/sustainable engineering

My research program

Background/Motivation

Concept of sustainability

Energy consumption pattern

Merits and demerits of bioenergy

Biofuel classification

Pathways for bioenergy production

Concluding remarks

Presentation outline

Exponential growth for resources in the last 50 years

Source: Energy Steffen, W.; Sanderson, A.; Tyson, P. D., et al. Global Change and the Earth Systems:

A Planet Under Pressure; Springer-Verlag: Heidelberg, Germany, 2005

Growth pattern and resource consumption

Ecological footprint

0

10.000

20.000

30.000

40.000

50.000

60.000

70.000

80.000

1960 1980 2000

Wo

rld

GD

P (

Cu

rre

nt

US$

in B

illio

ns)

Source: The World Bank, 2013

World GDP Growth

Population growth and affluence

Master equation of sustainability

Our Common Future (Brundtland report, 1987)

“Development that meets the needs of the present without compromising the ability of future generations to meet their own needs”

Profit People Protection

Sustainability

Th

e “

Trip

le B

ott

om

Lin

e”

Master equation of sustainability

EI = Population x x GDP EI

Person unit of per capita GDP

EI = Environmental Impact I

Population = Population Concerns P

GDP/PERSON = Affluence Concerns A

EI/Unit of Per Capita GDP = Technological Concerns T

First term increase by a factor of 1.5 in next half century.

Second term increase by a factor of 2 to 3.

Third term must be reduced by factor of 4 to 10, to hold the environmental impact where it is today.

The greatest hope rests upon the last term: sustainable or green engineering.

Energy

Environment

Food Safety

&

Security

Grand challenge (2050)

(a) Low energy society based on biomass in Nebraska, USA, 1886

(b) Complexity sustained by high rates of energy flows in Seoul

Energy transformations and complexity in society

(Source: P R. Ehrlich et al. Nature 486, 68-73 (2012))

Historical energy consumption

Charcoal is considered to be the first synthetic material created by mankind.

Ancient Egyptians used methanol produced from the

pyrolysis of wood.

Assyrians used biogas during 10th century for heating.

Wood distillation Plant (Veitch F.P., 1907)

Genesis of biofuel/bioenergy used

Middle Eastern jar with evidence of wine stained inside

8,500-4,000 B.C.

Mesopotamian scene suggests a gathering and drinking

(3,500-3,000 B.C.)

U.S. ethanol street lamps (c. 1920)

Henry Ford on first ethanol car (c. 1896)

Ford Focus E85 (Flex Fuel) (2014)

Historical timeline of biofuel (ethanol)

In 2010, the world

energy consumption was

about 524 QBtu

This is expected to

increased by 56%

between 2010 and

2040.

The US energy

consumption

is 95 QBtu.

http://www.eia.gov/todayinenergy/detail.cfm?id=12251

Country Crude oil consum. Million bbl/day

Total biofuel prod. thousand bbl/day

United States 18.49 (2012) 971.71 (2011)

Europe 14.42 250.49

China 10.28 46.80

Argentina 698.80 50.34

Brazil 2806.90 438.06

Africa 3.36 0.79

Colombia 0.287 15.00

World 89.20 1897.20

Energy consumption

Source: International Energy Outlook 2013 (IEO 2013)

Global energy consumption and forecast

Energy Independence and Security Act (EISA)

Originally called the Clean Energy Act of 2007

Advocates for:

Increased energy savings and efficiency

Appliances, lighting, etc.

Improved vehicle fuel economy

Increased biofuel use and production

Through the Renewable Fuel Standards (RFS)

• EISA mandates an increase in the volume of renewable fuel from 9 billion gallons in 2008 to 36 billion gallons by 2022

US energy policy

Why renewable energy?

1. Limited supply of current energy resources

2. Long-term energy security national security

3. Environmental issues: global warming/climate change

4. Support the rural economy

5. Availability of sufficient renewable resources

Source: USDA and USDOE, Apr 2005

Provides biofuels and biobased chemicals renewably

Improves environmental quality

Improves national security

Contributes to sustainable development

Why “bioeconomy”?

Biofuel/bioenergy classification

The classification is based on types of feedstock used: 1st generation biofuel 2nd generation biofuel 3rd generation biofuel

1st generation biofuels

Bioethanol

Sugar-based feedstocks: sugarcane, sugar beet, and sweet sorghum

First generation biofuels are produced from plant-derived feedstocks traditionally grown for food and feed purposes.

1st generation biofuels

Bioethanol

Starch-based feedstocks: corn, cassava, and sorghum grain

1st generation biofuels

Biodiesel

Oilseed feedstocks: soybean, rapeseed, palm oil

Waste oil and animal fats

Biomethane

Biogas produced during anaerobic fermentation of organic wastes, residues, animal manure

2nd generation biofuels

Bioethanol

Lignocellulosic biomass: crop and forest/wood residues, energy crops (e.g. corn stover, bagasse, wood chips, energy crops etc.)

Second generation biofuels are produced from non-food crops.

Biobutanol

Through acetone, butanol & ethanol (ABE) fermentation by clostridia class of microbes

2nd generation biofuels

Biodiesel

Oil seed from non-food crops

(e.g. Jatropha, camelina)

Synthetic diesel

Gasification and catalytic conversion to produce synthetic diesel from syngas

Bio-oils

Pyrolysis of biomass

Platforms for bioenergy & biobased products

Platform

Biochemical Thermochemical Carboxylic acids

Sugarcane-ethanol

Corn-ethanol

Organic waste- biogas

Cellulosic biomass- biofuels

Combustion (heat and electricity)

Gasification (syngas)

Pyrolysis (char, bio-oil)

Transesterification (biodiesel)

Acetic acid

Propionic acid

Caproic acid

Distillation Ethanol Drying

Vinasse/Stillage

Sugarcane-based ethanol

Cellulose

Conversion

Hydrolysis

Starch-based ethanol

Cellulose-based ethanol

Cellulose

Pretreatment Cellulose

Ferment-

ation Sugar

Sugar

Cane

Corn

Kernels

Starch

Conversion

(Cook or

Enzymatic

Hydrolysis)

Animal Feed or

Solid fuel Separator

Biochemical pathways

Ester

Sugar cane/molasses ethanol biorefinery

Crushing/expeller Sugar

extraction

Distillation

Dehydration

Anhydrous fuel ethanol, 200 proof

Bagasse

Sugar beet, sugarcane

Heat & power

production

Fermentation

CO2

Steam

Sugar

Molasses

Vinasse

Animal feed/ land application

Denaturated ethanol

5% gasoline

E10 and E85

Yeast

Dry milling process for ethanol production

Enzymatic hydrolysis of starch to glucose

Alpha-amylase

Glucoamylase

Debranching

Requires two types of enzymes:

Alpha-amylase

Glucoamylase

Cellulosic ethanol biorefinery

Anaerobic digestion

Biochemical pathway

Biomass

Waste

Manure

Agri-residues

Industrial waste

Digester

Biogas

CHP Unit

Heat

Electricity

Digestate for

land applications

Cleaning/ upgrading

Gas grid

CH4 gas

AD in developing countries

Household swine waste

anaerobic digester, Morelia,

Mexico

Household digester for developing countries

Thermochemical pathway

Primary air

Secondary air Flame

Coal

Incandescent coke

Grate

CO+CO2+N2+H2

VM+CO+CO2+N2+H2

O2+CO2+N2+H2O

Ash

Combustion rapid oxidation of fuel to produce

energy in the form of heat

Combustion Produces heat

Thermochemical pathway

Thermochemical pathway

Gasification High temperature (750 to 850oC) conversion of

solid carbonaceous fuels into flammable gas mixtures known as

producer gas: CO , H2, CH4, N2, CO2 and some higher hydrocarbons

SORBENT/ BED MATERIAL

FUEL:

Coal, Biomass,

Wastes

GASIFIER

AIR

or Oxygen

STEAM

ASH AND SPENT

SORBENT

Products (syngas):

CO (carbon monoxide)

H2 (hydrogen)

(CO/H2 ratio can be adjusted)

By-products:

H2S (hydrogen sulfide)

CO2 (carbon dioxide)

Solids (minerals from fuel)

Gas

Cleanup

Before

Product

Use

Process Conditions:

Pressure = 1 to 60 atm or more

Temperature =1600 – 2600 °F

Pyrolysis Thermochemical process that occurs in the absence of

air/oxygen at temperatures between 350 and 600 C. This process is

used for the production of charcoal or liquid products (also known as

tar or bio-oil).

Steam ReformingNatural gas

Steam

Gases

Gasoline

Diesel

Hydrocracking and

product separation

Mild

HydrotreatmentFast pyrolysis

Bio-oil

Hydrogen

Char

BioamssBiomass

Thermochemical pathway

Biodiesel biorefinery

100 lbs. of oil + 10 lbs. methanol =

100 lbs. FAME + 10 lbs. of glycerin

Hydrotreat Dehydrate

Oligomerize Hydrotreat

Hydrotreat Dehydrate Oligomerize

Conventional Refining/Petrochemical Units

Conventional Refining/Petrochemical Units

C3

Fermentation

C2

Fermentation

Gasification

Pretreatment

/Hydrolysis Sugars

Lignin

Jet Acetic

Acid

Propionic

Acid

Oligomerize Hydrotreat Diesel

Gasoline

Propylene

Ethylene

Ethanol

Hydrogen

(to Hydrotreating)

Steam, Power

Biomass

Carboxylic-acid platform

5-C sugars: C5H10O5 2.5 Acetic acid

6-C sugars: C6H12O6 3.0 Acetic acid

Homoacetogens: Moorella thermoacetica

Disadvantage of biofuel/bioenergy

• Potential impact on food/feed supplies due to land

use.

• Possible increase in agricultural products prices. (due

to biofuel feedstocks production)

• Likely to impact biodiversity.

• Degradation of soil quality/soil erosion.

• Increased use of fertilizer and pesticides.

• May impact water quality and quantity.

o Cellulose o Hemicellulose o Lignin o Others (extractives and ash)

Photo courtesy: http://www.nature.com/scitable/content/structure-of-lignocellulose-14464273

What is lignocellulosic biomass?

Biomass structure

Pretreatment is essential to facilitate easy access

of enzymes to cellulose/hemi-cellulose:

1. To solubilize lignin.

2. To dissolve hemi-

cellulose.

3. To disrupt a

cellulose-

hemi-cellulose

-lignin interaction.

Biomass pretreatment

Enzyme hydrolysis for sugar release

Endoglucanase

Attacks amorphous, non-crystalline regions of

the chain producing oligosaccharides

Exoglucanase

(Cellobiohydrolase)

Attacks chain ends producing

cellobiose

β-glucosidase

Attacks cellobiose producing

glucose

Pretreatment &

fractionation

Lignocellulosic biomass Organic wastes/ Residues

Enzymatic hydrolysis

Thermo-chemical conversion & synthesis

Fermentation

Separation & upgrading (cracking/hydrotreatment)

Anaerobic digestion & Gasification

Liquefaction/ pyrolysis

Catalytic conversion or syngas fermentation

Heat/Power H2, CO CH4

Cellulose

Hemi- cellulose

Bio-oil bio-crude

Lignin

Heat Electricity Hydrogen Diesel fuel Jet fuel Methanol DME Ethanol Butanol Lactic acid Levulinic acid Furfural HMF DMF … Phenolics Resins Adhesives Fuel additives Surfactants …

Primary Secondary

Lignocellulosic-based biorefinery

Bioenergy is the largest portfolio of total renewable energy. In developing countries, bioenergy has been playing critically important role in supplying the energy needs.

Although first generation biofuels (ethanol and biodiesel) currently dominate the biofuel supply, there is significant achievement in converting non-food crops to renewable biofuels.

Major challenge with cellulosic-biofuel is production cost. The costs of feedstock, pretreatment, enzymes are the major contributors of overall cost.

Energy policy and the environmental impact (climate change) may play key role in the shift towards bioenergy.

Concluding remarks

OmniGreen Renewables

Acknowledgements

Research group

Rakshit Devappa Zhen Hu Devin Takara Saoharit Nitayavardhana Pradeep Munasinghe

Surendra K.C. Majdouline LeRoy Ed Drielak Matt Wong

Nora Robertson Lindsay Fujii Sarah Tamashiro Elise Minkin

Kerati Issarapayup

Jessica Schmidt Shilva Shrestha

Sumeth Wongsview

Duc Nguyen Chayanon Sawatdeenarunat

Books on bioenergy

Textbook on Bioenergy (Undergraduate)

Title: Bioenergy: Principles and Applications

Publisher: John-Wiley Publishing

Release date: Fall, 2014

Thank you

Questions/comments