Intro IPCC-model, Copenhagen

TNO Environment, Energy and Process Innovation

Introduction to 2006-IPCC guidelines

Workshop CH4 from waste, March 8th -9th, 2006

Intro IPCC-model, Copenhagen

In the next hour

• Changes compared to previous methods• Some backgrounds

• Why 1st order decay model (FOD)• Changed mathematics FOD• Single-phase vs. multi-phase• Why default oxidation• Measuring and estimating recovery

• Default values• Introduction to the spreadsheet-model

Intro IPCC-model, Copenhagen

Methane emissions

emission =

(formation – recovery)*(1-oxidation)

Intro IPCC-model, Copenhagen

Most important changes compared to ‘96 RG and ‘00 GPG

• Improved estimate of waste and DOC• 1st order decay model (FOD) strongly recommended• and facilitated in a model• slightly different mathematics FOD• improved default values

• Waste generation• Waste composition• Model parameters

• recovery preferably measured, conservative estimation

methodology introduced• C-storage, harvested wood in landfill

Intro IPCC-model, Copenhagen

Estimating DOC landfilled

Default values for• MSW-produced• Other wastes produced• Composition waste• DOC-content waste fractions• Fraction landfilled

• Historical development amounts waste

Intro IPCC-model, Copenhagen

Estimating DOC landfilled (2)

Bulk waste approach:

• Little information available

• MSW-generated * % landfilled = MSW landfilled

• MSW landfilled * DOCMSW = DOC in MSW landfilled

Intro IPCC-model, Copenhagen

Estimating DOC landfilled (3)

Material stream approach:

• Country specific information available

• MSW-generated * % landfilled = MSW landfilled

• MSW landfilled * % food waste = food waste landfilled

• Food waste landfilled * DOCfw = DOC in food landfilled

Intro IPCC-model, Copenhagen

Calculation of methane formation

• Methane potential as in ‘96-RG and ’00-GPG

L0 = 0,5 * 16/12 * DOCf * DOC * MCF

• Defaults for DOCf and MCF

• Delayed release of methane potential:

first order decay (FOD)-model

Intro IPCC-model, Copenhagen

Why FOD?

• Methane is formed throughout decades• Starting point emission inventory: ‘where and when’• GPG, 2000: ‘Important when practices change rapidly’• GPG, 2000: ‘1996-default method overestimates effect of

reduced landfilling in the period 1990-2010, FOD is good

practice’• For transparency reasons FOD for all countries

Intro IPCC-model, Copenhagen

Better estimation of emission reduction

Intro IPCC-model, Copenhagen

Better estimation of emission reduction (2)

Intro IPCC-model, Copenhagen

Changes to ‘96-guidelines/’00-GPG

• Facilitated by development of internet• More complicated methodology• Still easy to use

• Reason for changes

Intro IPCC-model, Copenhagen

Changes in algorithm

• FOD 1996:

formation = L0 * k * e-kt (1)

• GPG ’00: correction factor

• FOD 2006:

formation = L0 * (e-k(t-1)-e-kt) (2)

• Validated older models (1) are not „wrong“

Intro IPCC-model, Copenhagen

Single-phase vs. Multi-phase

• Waste is not waste but food, paper, wood, etc.

• Single-phase• Average k-value for all streams• Reactions are fully dependent• Decay of food waste is delayed and wood waste is accelerated

• Multi-phase• Discrete k-values for each stream• Reactions are fully independent• Wood is wood and degrades as wood, irrespective of other wastes present

Intro IPCC-model, Copenhagen

Single-phase vs. Multi-phase (2)

• Truth will lie in the middle• No experimental support for either of both options• No theoretical support for either of both

• Both options are facilitated in the model

Intro IPCC-model, Copenhagen

Recovery

Starting point ‘00 GPG: • only measured amounts recovered!!!!!• (recovery estimates tend to be way too optimistic)

’06-guidelines: • Measurements highly recommended• Conservative default estimation methods introduced• 20% recovery efficiency• 35% of installed capacity

Intro IPCC-model, Copenhagen

Recovery (2)

Few measurements available:• 10-85% efficiency (Netherlands: 37% average)• However mostly closed landfills

Most relevant landfills still have parts in exploitation

Conservative default efficiency: ~20% (Dutch experience, to my opinion not that conservative)

Intro IPCC-model, Copenhagen

Recovery (3)

Recovery and flare capacity• Conservative default utilisation factor: 35%• Based on US and Dutch experiences

Main reasons for non-use• Overestimated gas formation – Overdesigned equipment• Poor working hours (down to 80%)• Back-up systems

Intro IPCC-model, Copenhagen

Oxidation default value: 10%

No change compared to ’96-RG and ’00-GPG

May be higher, but highly uncertain• Very difficult to measure

• 13C-analysis

• CO2 and CH4 mass balance

• Heterogeneous pathway of emissions due to cracks, etc.

• Highly variable (CH4-flux, soil-type, vegetation)

• Dependent on climatological conditions, season• Few data available