Life cycle assessment of tea

produced in Kenya

Professor Adisa Azapagic

Climate Change the Tea Sector in Kenya: Impact Assessment and Policy Action

National Multi-Stakeholder Workshop, 29-30 April 2013, Naivasha

LCA methodology

1.Goal and scope definition

-Purpose of the study

-System boundaries

-Functional unit

2. Inventory analysis

-System definition

-Data collection

-Estimation of environmental

burdens

3. Impact Assessment

-Selection of impact

categories

-Estimation of impacts

4. Interpretation

Identification

of significant

issues

Evaluation of

results

Conclusions

Goal and scope of the study

Goal

To estimate the carbon footprint of tea production in

Kenya

Scope

From ‘cradle to grave’

Functional unita:

1 kg of dry tea

1 tea cup

System boundaries

GHG emissions and

wastes

Tea

cultivation

Tea

processing

Use

Disposal

Primary resources

(materials, energy)

From ‘cradle to grave’

ENVIRONMENT

T T T

T = transport

Fuel

TRANSPORT

Primary packaging

USE (UK)

PACKAGING TEA CULTIVATION

AND HARVESTING

RE-PACKING AND STORAGE

(Mombasa)

Fertilisers Secondary packaging

Tertiary packaging W

AS

TE

MA

NA

GE

ME

NT

W a s t e

w a

t e r

t r e a t m

e n

t

Recyclin

g/D

isp

os

al

Other waste

TEA PROCESSING

Withering

Maceration

Sorting

Drying

Oxidation

Fuel

TRANSPORT

Wastewater

Fuel

TRANSPORT

Fuel

TRANSPORT Utilities

(Electricity, steam,

water)

Fuel

TRANSPORT

Primary packaging

Cut, Tear, Curl (CTC)

Farm machinery and fuel

Electricity

Made tea (1 kg)

Packing

System boundaries

System boundaries

All activities from cultivation to end-of life,

including

Land use change

Direct and indirect emissions from fertiliser use

Transport

Packaging

Consumer preparation of tea

Waste management options

Data and assumptions:

Average production from 2007-2012

Fresh tea leaves 16,350-19,650 t/yr

Dry tea 3600-4350 t/yr

Fresh tea per kg or

dry tea ~4.5 kg/kg

Data and assumptions:

Land use change

New land each year 37-136 ha/yr

Average land under

cultivation 1200-2000 ha

Data and assumptions:

Energy

Source

Amount

(kWh/kg tea)

Tea

production Electricity 0.44-0.56

Heat (wood) 4-23

Use Electricity 14

Total 18-37

Data and assumptions:

Packaging

Fertiliser PE bags

Fresh tea

HDPE bags

PP bags

Dry tea, large bags

Paper for the bag

Aluminium for the bag lining

Polyethylene for the bag

HDPE for the bag lining

Polyethylene film

Wood

Slip sheet (compacted carton)

Dry tea, small pack Kraft paper

Corrugated cardboard

Bleached board

PE film

Cellulose

Total packaging:

~1.1 kg/kg tea

Data and assumptions:

Transport

Material Mode Distance (km)

Fertiliser 40 t truck 11920

Fertiliser bags 40 t truck 11920

Fresh tea 7.5 t truck 7-14

Large tea bags 7.5 truck 200-300

Pallets 7.5 truck 50

Slip sheets 7.5 truck 85

Tea (to Mombasa) 40 t truck 720

Tea (to UK) Shipping 11,200

Tea (to Manchester) 40 t truck 400

Tea (to retailer) 22t truck 300

Total ~36,800

Data and assumptions:

Waste

All waste assumed landfilled except for

paper/cardboard packaging disposed off in the

UK

80% recycled (UK average)

system credited for recycling

Carbon footprint of Kenyan electricity

0.436

0.00

0.10

0.20

0.30

0.40

0.50

GW

P (

kg

/kW

h)

Oil Biofuels Hydro Geothermal

Carbon footprint of 1 tea of dry tea:

‘Cradle to gate’

0.55

2.27

0.06 0.13

3.01

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50R

aw

mate

rials

Pro

ductio

n

Sto

rage

Tra

nsport

(up to

sto

rage)

Tota

l

GW

P (

kg

CO

2 e

q./kg

dry

tea)

Carbon footprint of 1 tea of dry tea:

‘Gate to consumer’

0.38

9.389.00

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

Use

Tra

nsport

(to

consum

er)

Tota

l

GW

P (

kg

CO

2 e

q./kg

dry

tea)

Carbon footprint of 1 kg of dry tea:

‘Cradle to grave’

0.55

2.27

0.06

9.00

0.51

12.40

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00R

aw

mate

rials

Pro

ductio

n

Sto

rage

Use

Tra

nsport

Tota

l

GW

P (

kg

CO

2 e

q./kg

dry

tea)

Contribution to the total carbon

footprint

Raw materials

4.42%

Production

18.34%

Storage

0.47%

Use

72.65%

Transport

4.12%

Contribution analysis:

Carbon footprint of raw materials

0.55

1.62E-03 0.00 0.00 0.00

0.55

0.00

0.10

0.20

0.30

0.40

0.50

0.60

Raw

materials

Packaging Waste Energy Land use

change

Total

GW

P (

kg

CO

2 e

q./kg

dry

tea)

Contribution analysis:

Carbon footprint of raw materials

0.02 0.02

0.44

0.021.63E-03

0.04

0.55

0.00

0.10

0.20

0.30

0.40

0.50

0.60

Alu

min

ium

fo

il

(fro

m v

irg

in

Al.)

Fe

rtilis

er,

K

Fe

rtilis

er,

N

Fe

rtilis

er,

P

Ta

p w

ate

r, a

t

use

r, U

K

Ta

p w

ate

r, a

t

use

r, U

K

To

tal

GW

P (

kg

CO

2 e

q./kg

dry

tea)

Contribution analysis: Carbon

footprint of production and packaging

0.49

0.00 0.03 0.00 0.00 0.00

0.27

0.00 0.03

1.46

2.27

0.00

0.50

1.00

1.50

2.00

2.50

Culti

vatio

n

Pru

nin

g

Harv

estin

g

With

ering

CT

C-M

acera

tion

Oxid

atio

n

Dry

ing

Sort

ing a

nd e

quip

ment

cle

anin

g

Tea p

ackin

g a

t fa

cto

ry

Post-

facto

ry tea p

ackin

g

Tota

l

GW

P (

kg

CO

2 e

q./kg

dry

tea)

Contribution analysis: Carbon

footprint of storage in Mombasa

0.02

0.00 0.00

0.04

0.06

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Energy Direct emissions Packaging Waste Total

GW

P (

kg

CO

2 e

q./kg

dry

tea)

Contribution analysis:

Carbon footprint of use

9.20

0.00

-0.20

0.00

9.00

-2.00

0.00

2.00

4.00

6.00

8.00

10.00

Energy Direct emissions Waste Carbon storage Total

GW

P (

kg

CO

2 e

q./kg

dry

tea)

Contribution analysis:

Carbon footprint of transport

0.09

0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.000.04

0.00 0.00

0.37

0.00 0.00 0.00 0.00

0.51

0.00

0.10

0.20

0.30

0.40

0.50

0.60

Ra

w M

ate

ria

ls--

->P

roce

ssin

g

Cu

ltiv

atio

n--

->

Pru

nin

g--

->

Ha

rve

stin

g--

->

With

eri

ng

--->

CT

C-M

ace

ratio

n--

->

Oxid

atio

n--

->

Dry

ing

--->

So

rtin

g &

eq

uip

me

nt cle

an

ing

--->

Te

a p

ackin

g a

t fa

cto

ry--

->

Po

st-

facto

ry te

a p

ackin

g--

->

Pro

ce

ssin

g--

->S

tora

ge

Sto

rag

e--

->U

se

Ra

w M

ate

ria

ls--

->W

aste

Pro

du

ctio

n--

->W

aste

Sto

rag

e--

->W

aste

Use

--->

Wa

ste

To

tal

GW

P (

kg

CO

2 e

q./kg

dry

tea)

Contribution analysis:

Carbon footprint of waste

0.00

0.07

0.04

-0.20

-0.08

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

Raw materials Production Storage Use Total

GW

P (

kg

CO

2 e

q./kg

dry

tea)

Comparison of small and large-scale

tea production

0.3

3

9.6

6

1.4

4

0.1

8

0.4

9

12.0

6

0.5

5

9.4

9

1.4

5

0.3

3

0.5

1

12.4

0

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

Raw

Materials

Energy Packaging Waste Direct GHG

emissions

Transport Total

GW

P (

kg

CO

2 e

q./kg

dry

tea)

KTGA (average) KTDA (average)

Comparison of results with literature

6.029.6

5.3

24.8

49.5

39.7

0

10

20

30

40

50

60

Kenyan tea (this study) Darjeling tea (Jungbluth et

al., 2010)

Unspecified tea from Asia

(Melican, 2009)

Cradle to gate (g CO2 eq./cup tea) Cradle to grave (g CO2 eq./cup tea)

Conclusions

Carbon footprint of tea from ‘cradle to gate’: ~3 kg CO2 eq./kg dry tea

From ‘cradle to grave’: ~12 CO2 eq./kg dry tea

Main contributors: Consumer (70%)

Production (20%)

Raw materials (4%)

Transport (4%)

The results are sensitive to the assumptions for energy use in the consumption stage