Biomass and Bioenergy

1
Biomass and Bioenergy

• Approaches to Assessing Greenhouse Gas Mitigation
  Potential
• Carly Green

20 November 2003
IEA Bioenergy Task 38 National Meeting - Ireland
University College Dublin
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Introduction

• What is biomass?
• Why calculate GHG benefits
• The Carbon Cycle
• Options for biomass
• How are GHG benefits calculated
• Life Cycle Analysis
• Case Studies

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What is biomass?

• Accumulates in living vegetation following
  photosynthesis
• Important pool in the carbon cycle
• Exists in many forms
• Contributes to other pools within the global
  system

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The Carbon Budget
(Source Broadmeadow and Matthews, 2003)
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Greenhouse gas mitigation options

• Fuel for Energy
• Dedicated Sources (i.e. by-products of other
  activities)
• Dependant Sources (i.e. energy crops grown
  specifically for food)
• Carbon Sink
• Wood Products

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Fuel for Energy

• Long use history (i.e. centuries)
• Currently contributes 14 to the global energy
  requirements
• More efficient use through modern technology
• Solid liquid and gas
• Capable of replacing all fossil fuel energy forms

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Fuel for Energy (cont.)
a. CO2 captured by growing crops and forests
b.O2 released and C is stored in the biomass of
plants
c.C in harvested biomass is transported to the
power station
d.Released C from burning biomass is made
available again.
Recycling of carbon Source IEA Bioenergy Task
38
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Carbon Sink

• Recent Policy has focused on this option
• Kyoto Protocol Article 3.3
• Increase carbon stock in various pools
• Aboveground / belowground and soil
• Time Dependant
• Land use change

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Carbon Stock Dynamics
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Wood Products

• Product replacement
• Sink
• Fuel at end of life

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Why calculate GHG benefits

• Analyse potential
• Quantify benefits
• Compare options
• Quality decision

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Life cycle analysis considerations

• Carbon stock dynamics

• Trade-offs and synergies

• Leakage

• Permanence

• Emissions factors

• By-products

• Efficiency

• Upstream/downstream emissions

• Other greenhouse gases

Task 38 standard methodology for calculating GHG
emissions Source IEA Bioenergy Task 38
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Constraints

• Must compare systems within same system boundary

• Information (data) sources
• Boundary selection
• Restricted analysis

Task 38 standard methodology for calculating GHG
emissions Source IEA Bioenergy Task 38
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Bioenergy Case Study 1
GORCAM output Source IEA Task 38
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Bioenergy Case Study 2a

• Ethanol production in Brazil vs United States
• Potential CO2 emissions avoided
• Brazil 5.6 MtC/yr
• United States 0.59 MtC/yr

Source Kheshgi and Marland, 2000
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Bioenergy

• Bioenergy output to fossil energy input
• Forestry and agriculture (25-50 1)
• Liquid energy (4-5 1)
• Source Marland, 1999

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Bioenergy Case Study 2b
Austria Fuel cycle analysis of Power plants
Source Jungmeier et al, 1999
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Canada Total Forest Ecosystem Carbon Modelling
(1920 - 1995)
Case Studies - Sink

Source Kurz and Apps, 1999
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Case Study - Sink
New Zealand Long-term average carbon density

• Typical radiata pine regime

Source IEA Task 38, 2003
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Case Study Wood Products
Product Replacement

• 1 kilometre of transmission line
• Life 60 years
• Including disposal

Emission in tonnes of CO2 equivalent to construct
Source Matthews and Robertson, 2002
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Case Study Wood Products
CanadaForest Products Carbon Storage
Source IEA Task 38, 2003
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Preferential Use
Source Matthews and Robertson, 2002
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