Life cycle energy use and GHG emissions of microalgal

Life cycle energy use and GHG emissions of

microalgal biodiesel in China

Zhang Tingting, Xie Xiaomin, Huang Zhen Research Center for Combustion &

Environmental Technology

SJTU

The 7th Annual CE-CERT-SJTU Student Symposium

Outline

Backgrounds 1

Methodology 2

Results and discussions 3

Conclusions and prospects 4

Backgrounds

1.1 Challenges to global transportation energy

Energy security

Global warming

Atmosphere pollution

Energy security

2009 fuel shares of

total final consumption

2009 shares of

oil consumption by sector

Data source: from IEA

Total final consumption worldwide is dominated by oil. 61.7% of oil is used

for transport in 2009.

Energy security

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100

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1 2 3 4 5 6 7 8 9

R/P

ra

tio

n

Oil

pro

ve

d r

es

erv

es

: t

ho

us

an

d m

illi

on

to

ne

s

2010 world oil proved reserves and R/P ration

Oil proved reserves R/P ration

1-US; 2-China; 3-North America; 4-S. & Cent. America; 5-Europe

&Eurasia;6-Middle East; 7- Africa; 8-Asia Pacific;9-Total World

Data source: from BP

Energy security

118.4

43.7

28.8 33.3

24.1

12.7 10.1 7 2.7 2.5

7.2 1.3 2.7

0

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40

60

80

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Cru

de o

il i

np

ort

s:

Millio

n t

on

nes

2010 Crude oil imports and compositon in China

Data source: from BP

55% of crude oil in China are mainly imported from Middle East and

West Africa. It might cause oil security issue, as the situation in these

regions are complicated.

Global warming

Data source: from IPCC

Global warming

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9000

China US Canada India Italy Japan

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tal C

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China US Canada India Italy Japan

CO

2e

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po

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: tC

O2/c

ap

ita

CO

2-G

DP

usi

ng

ex

cha

ge

ra

tes:

k

gC

O2/U

S d

all

ar

CO2-GDP CO2-POP

2010 CO2 emissions for different countries

With the development of modern society, China is becoming the

largest CO2 emission country, except for CO2-POP.

Data source: from BP(the left one,2010) & IEA(the right one,2009)


Population

explosion

Increasing energy

consumption

Fossil fuel use Automotive

emission

Air pollution

Acid rain Photochemical smog Poor visibility


According Aaron van Donkelaar et al.’s research, the concentration of

PM2.5 in Eastern China is extremly high.

Data source: A. van Donkelaar et al.

Backgrounds

1.2 Solution —— Biomass energy

First generation biofuel

Second generation biofuel

Third generation biofuel

First generation biofuel

The first generation biofuels are derived from food crops (e.g. corn,

soybean) that are rich of sugar, starch, and lipids to generate bioethanol

and biodiesel. It may cause food security issues.

Second generation biofuel

The second generation biofuels are derived from agricultural and forestry,

waste, switchgrass, jatropha seeds, palm oil et al. to generate bioethanol

and biodiesel. Although they avoid the land competition with grain, the

collection and disposal of the biological waste are difficult.

Third generation biofuel

Microalgae is known extensively as the newly emerging biofuel feedstock,

which would be used to produce biodiesel, bio-oil, cogenaration with biogas,

et al.

Why microalgae ?

Advantages:

High area productivity;

Minimizes competition with conventional agriculture;

Utilizes a wide variety of water sources;

Recycles stationary emissions of CO2;

Compatible with integrate production of fuels and co-

products within biorefineries.

Contrast of several kinds of raw materials used for producing

biodiesel to meet the fuel need of transportation in China

Crops Annual

output

(ton/acre)

Oil content

(%)

Annual oil

output

(ton/acre)

Land

requirements

(104 acre)

Land

requirements

to cultivated

land (%)

Soybean 1.449 16 0.2320 27605.21 225.45

Corn 5.28 9 0.4752 13468.01 110.00

Castor 1.005 58-75 0.5829-0.7538 8490.88-

10979.59

69.34-89.67

Rapeseed 1.837 37.5-46.3 0.6889-0.8505 7524.71-

9290.51

61.45-75.86

Jatropha 4.8 50 2.4 2666.67 21.78

Oil sally beans 12 25 3 2133.33 17.42

Palm 7.4 50 3.7 1729.73 14.12

Microalgae 166.3 30 49.89 128.28 1.05

microalgae 166.3 70 116.36 54.98 0.45

Data source: from Tong Mu, Zhou Zhigang.

Development of microalgal biodiesel

Time Researchers Project key points

1950s Meiser , Oswald & Golueke Utilization of carbohydrate of algal cells to

produce methane via anaerobic digestion.

1978-1996 U.S. DOE’s NREL Aquatic Species Program pushed by the oil

embargo and energy price surges ($25 million).

1968-1990 U.S. DOE Marine Biomass Program: produce fuels to

substitute natural gas with macroalgae.

1990-2000 MITI Japan The Earth Update Technology Research Plan:

photobioreactor.

2006-now GreenFuel、Livefuels 、Shell、Chevron、PetroSun、AlgaeLink、Diversified、Solazyme et al.

Fully launched the biofuel production from

microalgae.

2000-now

in China

Research institution: Tsinghua University, East China University of Science

and Technology, CAS, SJTU, Xiamen University, et al.

Enterprise: ENN, SINOPEC, Gloden Race Group Co., Ltd. et al.

Time Incidents

1969 LCA was derived from the resource consumption and

environmental analysis of beverage bottle at Coco-

Cola Company.

1990s Methodology of LCA was gradually consummate in the

promotion of SETAC.

1996 LCA was brought into ISO (ISO14000).

1997 ISO14040, 14041, 14042 and 14043 were issued.

Business software SimaPro 7, GaBi 4 et al.

Freeware GREET, GHGenius、TRACI、EIO-LCA、Tsinghua-

CA3EM

1.3 LCA of biofuels

LCA (Life cycle assessment) is a “cradle-to-grave” analysis for accessing

the resource use and environmental impacts and tradeoffs of industrial

systems and processes.

Application of LCA of biofuels

Corn

Wheat

Cassava

Switchgrass

Soybean

Rapeseeds

Jatropha seeds

Bioethanol

Biodiesel

Methanol

Biogas

Vehicle use

WTT TTW

1.4 Research questions

Microalgal biodiesel

Energy consumption

???

Environmental impacts

???

Water

use

???

2 Research methodology

Culture

Harvesting

Extraction

Conversion

Biodiesel

Water & nutrients

recycle

Aftertreatment

Remnants Fish feed

Glycerin

Anaerobic

digestion

Biogas

Electricity generation

Export to the grid

Life cycle boundary

Life cycle boundary of microalgal biodiesel

Inventory analysis

Parameters units ORP 1 ORP 2

Length m 150 190

Width m 10 20

Depth m 0.3 0.3

Hydraulic mean depth m 0.28 0.28

Pond volume m3 994 2651

Mean liquid velocity m/s 0.3 0.3

Residence time day 10 13

Flue gas m3/day 1445 1926

Outlet flow rate m3/day 100 200

Culture ----- Open raceway ponds (ORP)

Algae species: Chlorella vulgris;

Growth rate: 0.017kg/(m2•day);

Concentration: 0.5 kg/m3(dry biomass);

TAG content: 14%;

CO2 concentration: 2.5%

Sunshine

Nutrients

CO2

Water

Algae

Inventory analysis

Dewatering

Microbial flocculation

Centrifugation

Solar energy

Oil extraction --- organic co-solvents

n-hexane;

Extraction efficiency: 90%

Co-products: extracted biomass

Oil conversion --- chemical transesterification

Methanol ;

Catalyst;

Ratio of methanol to oil: 56:1;

Extraction efficiency: 89%;

Co-products: glycerin

WTP (STP) energy consumption and GHGs among different BD blends

CD J-BD100 M-BD100-60

-40

-20

0

20

40

CD J-BD20 M-BD2010

15

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CD J-BD100 M-BD1000

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WT

P (

ST

P)

en

erg

y

co

nsu

mp

tio

n:

MJ/

MJ

Total energy

Fossil fuel

Petroleum

GH

Gs:

gC

O2-e

q/M

J

CD J-BD20 M-BD200.0

0.2

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0.6

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1.0

WT

P (

ST

P)

en

erg

y

co

nsu

mp

tio

n:

MJ/

MJ

Total energy

Fossil fuel

Petroleum

GH

Gs:

gC

O2-e

q/M

J

3 Results and discussions

Characteristics of M-BD

-The highest total energy consumption

- The highest fossil fuel consumption

- Energy efficiency: 17.4%

- The lowest petroleum consumption

- The lowest GHG emissions

BD20 blends VS BD100

- Lower energy consumption

- Higher GHG emissions

WTP details for BD from jatropha and microalgae

Energy intensity stages for M-BD

- Algae growing

- Oil extraction

J-BD M-BD

0.0

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MJ

J-BD M-BD-0.15-0.10-0.050.000.050.100.150.200.25

Petr

ole

um

co

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tio

n:

MJ/

MJ

Actual value

J-BD M-BD

-300

-200

-100

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G e

mis

sio

ns:

gC

O2-e

q/M

J

CO2 credits

BD T&D

Transesterification

Oil extraction

Feedstock transportation

Feedstock growing

Energy intensity stages for J-BD

- Jatropha growing

- Oil extraction

- Seeds transportation

CO2 credits (M-BD VS J-BD)

- Larger due to carbon fixation

ability.


BD production

process Fossil fuel split (%) Petroleum split (%) GHGs split (%)

Jatropha seeds Microalgae Jatropha seeds Microalgae Jatropha seeds Microalgae

1 Feedstock phase 45.41 69.85 115.15 132.53 50.50 78.80

1.1 Process energy 1.55 22.31 10.69 41.82 1.95 38.79

1.2 Fertilizer 35.69 47.54 36.91 90.71 38.11 40.01 1.2.1 N 17.91 45.07 3.57 61.74 14.15 36.66 1.2.2 P 7.04 1.54 9.51 14.32 8.69 1.96 1.2.3 K 1.54 0.22 4.36 4.34 2.22 0.33

1.3 Pesticide 0.04 0 0.16 0 0.05 0 1.4 Herbicide 0 0 0 0 0 0 1.5 Feedstock

transportation 8.13 0 67.39 0 10.39 0

2 Fuel phase 54.59 30.15 -15.15 -32.53 49.50 21.20

2.1 Oil extraction -13.84 5.99 -107.73 -257.33 3.68 4.55

2.2

Transesterification 66.74 23.56 78.54 190.71 43.65 15.87

2.23T&D 1.69 0.60 14.04 34.09 2.17 0.79

Stage contribution of biodiesel production process for jatropha and microalgae


Fossil fuel for M-BD are mainly used for algae growing. Petroleum are mainly

used for fertilizer production and process like dewatering. GHG emissions are

mainly concentrated on process energy and fertilizer production.

CD M-BD100 J-BD100 M-BD20 J-BD200123456789

Fo

ssil

en

erg

y

co

nsu

mp

tio

n:

MJ/

km

Vehicle operation

Fuel

Feedstock

Actual value

CD M-BD100 J-BD100 M-BD20 J-BD20

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ole

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MJ

CD M-BD100 J-BD100 M-BD20 J-BD20

-300-200-100

0100200300

GH

G e

mis

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ns:

gC

O2-e

q/M

J

WTW results for different fuel blends


WTW characteristics for M-BD100

- The highest fossil fuel consumption

but lowest petroleum consumption.

- the lowest GHG emissions.

- Microalgae culture stage

account for 73.8% of total

fossil fuel.

BD20 blends may be a

better choice in the near

future.


WTW results for fossil fuel contribution

The forms of fossil fuel are different in each fuel pathway.

- Petroleum is the main power source for diesel vehicle.

- Coal and NG are the main source for M-BD due to larger electricity use

and auxiliary materials consumption like methanol, fertilizer.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Baseline (CD) M-BD100 J-BD100

Fo

ss

il fu

el c

on

trib

uti

on

: %

Coal Natural Gas Petroleum


0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

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5.000

Baseline (GV) Baseline (CV) PHEV30 EV M-BD20

WT

W f

os

sil

fu

el

co

ns

um

pti

on

: M

J/k

m

Feedstock Fuel Vehicle Operation

WTW fossil fuel consumptions for M-BD20:

- High fossil fuel consumption at current technology level in China.

Strategies:

- Enhance production efficiency

- Improve the structure of electricity grid

- Apply the genetic modification of algae

WTW fossil fuel consumption results for different vehicles


-100.00

-50.00

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

Baseline (GV)

Baseline (CV)

PHEV30 EV M-BD20

WT

W G

HG

em

iss

ion

s: g

CO

2-e

q/k

m

Feedstock Fuel Vehicle Operation

WTW GHG emissions for M-BD20:

- Could reduce the GHG emissions due to carbon fixation

via photosynthesis.

WTW GHG emission results for different vehicles

4 Conclusions and Prospects

WTP results of M-BD showed the highest fossil fuel consumption

but good performance on petroleum consumption and GHG emissions .

WTP fossil fuel is 10 times higher than that of conventional diesel;

WTP petroleum consumption is 77.7% lower than that of CD;

WTP GHG emissions is 185.5% lower than that of CD.

WTW results of M-BD showed the same trends with WTP.

BD100 do not consume any fossil energy and petroleum during

vehicle operation stage.

Microalgae culture stage account for 73.79% of the life cycle fossil

fuel consumption.

Suggestions and Prospects

Life cycle model of M-BD should focus on integration of other

technologies to reduce the process fossil fuel use.

Wastewater treatment

Biogas production from anaerobic digestion of residual algae

Nutrients recycle

……

Life cycle results are sensitive by many parameters.

Production efficiency

Lipid content

Energy structure

Electricity grid mix

……

The co-products allocation should be further investigated.

Thank you！

Life cycle energy use and GHG emissions of microalgal

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