LCA of Burning Different Solid Biomass Substrates Itten.pdf · Fossil fuels cause higher GWP than...

LCA of Burning Different Solid Biomass Substrates

47th LCA Discussion Symposium Berne, 23. April 2012

René Itten, Niels Jungbluth

ESU-services Ltd., Uster, Switzerland

USE USE

www.esu-services.ch Page 2

Introduction

• LCI’s for direct combustion of biomass substrates

• Environmental impacts of direct combustion

• Quantify emissions and impacts

• Comparison biomass substrates to wooden and

fossil fuels

• Influence of the substrates and combustion

technology

Preliminary Study

• Potential Substrates:

– About 40 substrates

– Kernels, Shells, Pomaces and other wastes

– Mainly by-products and wastes

• Selected: Olive pomace, coffee grounds, poultry

litter, horse dung and pig slurry

• Based on data availability



Life cycle inventory analysis

• New LCI for combustion of different solid

biomass substrates

• Processes included:

– substrate preparation

– biomass combustion

– ash disposal

• Cut-Off approach for substrates


System overview olive pomace

Drying

Combustion

Dried Olive Pomace

Heat

Ash

Ash disposal

Olive Pomace

Emissions

Emissions

Heat

System Boundary

Olive pomace


System overview pellets

Pellet production

Combustion

Pellets

Heat

Ash

Ash disposal

Coffee GroundsPoultry Litter

Emissions

HeatElectricity

Emissions

System Boundary

Coffee grounds

Poultry litter

System overview dung and slurry


Mixing with Wood Chips

Combustion

Dung / Slurry Mixture

Heat

Ash

Ash disposal

Horse Dung / Pig Slurry

Emissions

Emissions

Wood Chips

System Boundary

Pig slurry

Horse dung


Disposal routes for the ash

Sanitary

Landfill MSWI

Landfarming

Ash Disposal

25 % 50 % 25 %

Ash disposal for biomass substrates modeled like for wood according to

ecoinvent

Flue gas treatment


Cyclone Electrostatic filter

Combustion technology


combustion technology and flue gas treatment with improvement

potentials

General description Device CycloneElectro-static filter

Comment

Olive pomace tubular reactor no no experiment in labCoffee ground pellets automatic furnace no no wood combustionPoultry litter pellets grate furnace yes no pilot plantHorse dung and wood chips

grate furnace yes yeswood combustion, filters did not work

Slurry solids and bark chips

boiler furnace no no wood combustion

Elemental c omposit ion

Olive pomaceCoffee ground

pelletsPoultry litter

pelletsHorse dung &

wood chipsPig slurry solids

& bark chipsWood, Logs

Unit kg/kg fuel, dry kg/kg fuel, dry kg/kg fuel, dry kg/kg fuel, dry kg/kg fuel, dry kg/kg fuel, dryCarbon C 47.00% 51.20% 40.00% 48.00% 46.50% 49.80%Hydrogen H 5.70% 5.50% 6.50% 5.50% 5.50% 6.00%Oxygen O 38.40% 40.40% 35.50% 37.30% 35.00% 44.00%Nitrogen N 1.10% 0.00% 3.83% 0.18% 2.20% 0.08%Sulphur S 0.10% 0.00% 0.00% 0.03% 0.43% 0.01%Ash content 7.70% 2.90% 14.20% 9.00% 10.40% 0.10%Total dry mass 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%Moisture content 14.00% 14.60% 15.00% 45.00% 61.00% 14.00%

Elemental composition


Biomass substrates have a higher nitrogen, sulphur and ash content

Manure mixtures are extremely wet fuels


Life cycle impact assessment • Functional unit: Provision of 1 MJ of useful heat

• Indicators: Ecological Scarcity 2006 and IPCC

GWP

• Main contributors ecological scarcity and GWP

• Heavy metal emissions into soil

0 50 100 150 200 250 300

olive pomace (15 kW)

coffee ground pellets (25 kW)

poultry litter pellets (300 kW)

horse dung and wood chips (600 kW)

slurry solids and bark chips (1000 kW)

mixed logs (6 kW)

wood pellets (15 kW)

mixed chips from forest (300 kW)


light fuel oil (100 kW)


natural gas (>100kW)

eco-points (UBP) per MJ of heat

Fuel

Emissions

Disposal ash

Rest

Fossil

Wood

Substrates

Page 13

Ecological Scarcity 2006

High emission during combustion lead to higher total impacts than for

conventional fuels

Page 14

Ecological Scarcity 2006 Air Emissions

Particle, NOX and Benzene emissions cause more than 50% of the

environmental impacts in case of the biomass substrates

0% 20% 40% 60% 80% 100%






mixed logs (6 kW)







Contribution relative to total Score BenzeneParticulatesNOxMethaneLeadN2OCadmiumDioxinSOxNMVOCCO2, fossilRestFossil

Wood

Substrates

Page 15

IPCC Global Warming Potential

Fossil fuels cause higher GWP than wood and biomass

0 20 40 60 80 100






mixed logs (6 kW)







IPCC GWP in g CO2-eq per MJ of heat non-CO2, fossilCH4, biogenicCO2CO2, land transformation

Fossil

Wood

Substrates

Page 16

Results: Soil emissions Soil Emissions Heavy Metals

Biomass substrates tend cause higher heavy metal emissions than wood

but the emissions are still comparable

Wood Wood Substrates Substrates

0

20

40

60

80

100

120

140

160

Lead, Soil, agricultural

Lead

em

issio

ns in

to so

il in

ug

per M

J of h

eat

0

1

2

3

4

5

6

7

8

9

10

Cadmium, Soil, agricultural

Cadm

ium

em

issio

ns in

to so

il in

ug

per M

J of h

eat




horse dung and wood chips(600 kW)slurry solids and bark chips(1000 kW)mixed logs (6 kW)


mixed chips from forest (300kW)mixed chips from forest (1000kW)

Subs

trat

es

Woo

d

Woo

d


Conclusions 1

• Biomass substrates cause higher impacts compared to

wooden and fossil fuels according to ecological scarcity

2006

• Biomass substrates cause lower greenhouse gas emission

compared to fossil fuels according to IPCC GWP

• Trade-off between GWP and overall environmental

impacts


Conclusions 2

• Particulate matter emissions cause the highest share of

the impacts according to ecological scarcity

• High uncertainty because lacking data regarding particle

distribution for biomass substrates

• Some of the biomass substrates cause higher heavy metal

emissions than wooden fuels but for most of the

substrates the heavy metal emissions are equal or lower

compared to wooden fuels


Conclusions 3 • No recommendation can be made regarding the furnace

type

• Data mainly for pilot plants without flue gas treatment

• High potential to reduce particle emissions with basic

flue gas treatment


Conclusions

Flue gas treatment is essential to minimize particle emissions during biomass combustion.

The use of biomass substrates can reduce greenhouse gas emissions, at the cost of increased particulate matter emissions.

Page 21

Thanks for your attention!

René Itten

[email protected]

www.esu-services.ch ESU-services GmbH, Uster, Schweiz

Acknowledgements: The work presented here was made possible thanks to financial support from the Swiss Federal Office for Energy (FOEN).

Download the study and electronic data: http://www.lc-inventories.ch/

http://www.lc-inventories.ch/


Additional Slides

Page 23

Results: Coffee grounds Direct combustion vs MSWI

Combustion in MSWI

Combustion in furnace

-1 -0.5 0 0.5 1

-800 -600 -400 -200 0 200 400 600 800

IPCC GWP in kg CO2-eq per kg coffee grounds

ecopoints (UBP) per kg coffee grounds

UBP'06 MAX UBP'06 MIN GWP MIN GWP MAX

Combustion of coffee grounds in MSWI causes lower impacts


Results: Scenarios for Ash Disposal Ecological Scarcity 2006

0

50

100

150

200

250

300

350

400

450

REF LAND MSWI MSWLF REF LAND MSWI MSWLF REF LAND MSWI MSWLF REF LAND MSWI MSWLF REF LAND MSWI MSWLF

olive pomace coffee ground pellets poulry litter pellets horse dung and waste woodchips

slurry solids and bark chips

UBP

per M

J of h

eat

Emission into air Emission into surface waterEmission into ground water Emission into top soilEnergy resources Natural resourcesDeposited waste


Results: Scenarios fuel preparation Ecological Scarcity 2006 and IPCC GWP

0

20

40

60

80

100

120

regionalstorage

on site regionalstorage

on site

coffee ground pellets poultry litter pellets

UBP

per M

J of h

eat

Emission into air Emission into surface waterEmission into ground water Emission into top soilEnergy resources Natural resources

0

0.005

0.01

0.015

0.02

0.025

0.03

regionalstorage

on site regionalstorage

on site

coffee ground pellets poultry litter pellets

IPCC

GW

P in

kg

CO2-

eq p

er M

J of h

eat

fossil, non-CO2CH4, biogenicCO2CO2, land trans


Substrates considered in this study (1)

Olive pomace Coffee grounds Poultry Litter pellets


Substrates considered in this study (2)

Horse dung and wood chips Slurry solids and wood chips

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