Methane emissions from biogas plants

The Swedish voluntary agreement system and sustainability criteria

Magnus Andreas Holmgren

SP Energy Technology

magnus.andreas.holmgren@sp.se

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BACKGROUND

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The origins 2004/2005

Media• Article in Svenska Dagbladet

2004 “Biogas as vehicle fuel has no environmental advantage”

• Losses in production and distribution of biogas

• Losses during filling

Research & Development• Program for evaluation of

biological treatment (BUS) in Sweden and Norway 2004-2005 covered methane emissions

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4 reasons to act on methane emissions

• Environment– Methane is a strong GHG (CO2 x 23)

– Odour

• Economy– Reduced leaks and emissions = higher yield

• Safety

• Goodwill– To show that the biogas sector acts responsibly– To be pro-active on this issue (in relation to authorities)

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The Swedish voluntary agreement systemlaunched in January 2007

• Methane only

• Waste Treatment plant focus

• All work reported to Avfall Sverige

• First round of measurements 2007-2009

• Second round of measurements is on-going 2010-2012

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Biogas upgrading plants• Boden• Borås• Eskilstuna• Falköping• Göteborg (WWT)• Helsingborg (x2)• Jönköping (x2)• Kalmar• Kristianstad• Laholm• Linköping• Malmö (WWT)• Norrköping• Norrköping (WWT)• Skellefteå• Skövde• Stockholm, Bromma (WWT)• Stockholm, Henriksdal (WWT)

Biogas production plants• Boden• Borås• Eskilstuna• Falköping• Helsingborg• Jönköping• Kalmar• Kristianstad• Laholm• Linköping• Linköping (WWT)• Norrköping• Skellefteå• Skövde• Uppsala• Vänersborg• Västerås• Wrams Gunnarstorp

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• Uppsala• Västerås• Wrams Gunnarstorp• Östersund (WWT)

DESCRIPTION OF THE SYSTEM

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How the system is set up

• System for leak detection at plant–Recommended monthly

• Systematic emission sources are identified–Classification plans

• Quantification every 3 years by external resource–Measurements of methane concentration and flow–Calculations of mass emission and percentage loss

• Plant sets targets and measures to reach targets• Plant reports to Avfall Sverige

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System boundaries, Gas production plant

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Biogas plant

Liquid waste

Digestate

Recieving tank

Hygienisation

Mixing tank

Digester

Torch

Bolier/Gas motor/ Upgrading plant

Pretreatment unit

Digestate tank

Dewatering

Digestate storage

Solid waste

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System boundaries, Gas upgrading plant

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Biogas pipeline

Propane addition

Compression

Hydrogen sulphide removal

Drying

Odorising

Upgrading plant

Gas grid

Off gas

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Typical measurement points for quantification

• Ventilation from process parts• Ventilation from buildings• Ventilation from rooms with gas equipment

• Digestion residue (digestate) storage• Digestion residue (digestate) treatment (centrifuge etc.)

• Gas analysis instruments

• CO2 emission from gas upgrading plants (off-gas, e.g. stripper air)

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Measurement methods

• International and European Standard Methods (ISO/CEN)–Methane concentration–Gas flow–Leak detection mass flow estimations

• Methane measurements handbook–SGC report no 227, February 2011– Aimed at measurement personnel– Section on strategies for leak detection– Calculation spreadsheets (Excel)– Default values

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Theory vs Reality

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Measurement section:5 diameters upstream2 diameters downstream

RESULTS

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Biogas production plants

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Biogas production plants

• Round 1: 2007-2009

• Rolling average: 2007-2012

Category Mean value Median

WWT 1,4 % 1,5 %

Household waste 2,0 % 1,1 %

Industrial waste 1,2 % 0,2 %

1,6 % 0,7 %

Category Mean value Median

WWT 1,5 % 1,8 %

Household waste 2,1 % 1,0 %

Industrial waste 0,8 % 0,3 %

1,5 % 0,3 %

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Gas upgrading plants

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Gas upgrading plants

• Round 1: 2007-2009

• Rolling average: 2007-2012

Technique Mean value Median

Chemical scrubber 0,4 % 0,4 %

End-of-pipe 1,7 % 1,7 %

PSA 2,5 % 1,8 %

Water scrubber 3,2 % 2,1 %

2,7 % 2,1 %

Technique Mean value Median

Chemical scrubber 0,2 % 0,2 %

End-of-pipe 1,0 % 0,7 %

PSA 2,5 % 1,8 %

Water scrubber 2,1 % 2,0 %

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IMPACT

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Improvements in industry

• Gas production plant, example– 2007: Loss 7,5 %– 2010: Loss <0,1 %

• Gas upgrading plant, example– 2008: Loss 12 %– 2010: Loss 7 %– 2011: Loss 2 %

• Focus on methane losses during design and in permits

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Poor impact on researchers and policy makers

• Scientific article: Anaerobic digestion and digestate use: accounting of GHG and global warming contribution– Losses from gas upgrading are estimated at 0,2 % (without

reference to anything)

• University study on GHG emissions from biogas, on assignment from Swedish Government– No reference to Voluntary Agreement

 

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Waste Water Treatment plants

• Aprox. 130 plants with biogas production in Sweden

• A few plants take part in the voluntary agreement

• Measurements (outside the system) have been performed at a few large plants

• In general there is poor knowledge of the size of methane emissions from WWT biogas plants

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SUSTAINABILITY CRITERIA

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Sustainability criteria for biofuels and bioliquids

• A given set of sustainability criteria that cover the entire production chain of a biofuel or bioliquid, from feedstock production to end use, shall be fulfilled for it to be considered sustainable

• The Swedish legislative framework concerning biofuels and bioliquids is based on the European Directive 2009/28/EC on the promotion of the use of energy from renewable sources (RED), and is aimed at suppliers and users of biofuels and bioliquids

• Covers biogas for vehicle use– Not heat and power!

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Sustainability Criteria for biogas as vehicle fuel

• GHG emission savings (LCA)– XX % better than the fossil reference case– Same reference case for all vehicle fuels!

”average emissions from the fossil part of petroland diesel”

– All plants from April 2013: 35 %– All plants from January 2017: 50 %– New plants from 2018: 60 %

• RED default value for biogas from municipal organic waste: 73 %– 1 % loss in production, 1 % loss in gas upgrading– Included: Household waste, WWT sludge– Not included: Industrial waste

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Voluntary Agreement and sustainability criteria

• Excel spreadsheet developed for the Swedish gas industries– In co-operation with Swedish Energy Agency

• Need for default methane loss values when measurements have not been performed

• Upper quartile of rolling average – 2,5 % production– 2,1 % upgrading

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Voluntary Agreement and sustainability criteria

• Using the default methane loss values:– 2,5 % loss in production, 2,1 % loss in gas upgrading– GHG emission savings: 56 % (prel.)

• Add to this the actual values for:– Transportations of substrate (zero in RED default value!)– Transportations of produced biogas– Process energy use

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Sustainability criteria for biogas used in heat&power

• Legislation/recommendations that would cover gaseuous fuels for heat and power (+ solid fuels)

• According to yesterday’s presentation by Mr Kuepker, DG Energy:– Not yet decided if they will present directive or recommendations

• The reference case for GHG emission savings calculations might be different to the present directive!!– Natural gas for heat and power would be the natural reference!

• Tough times ahead…?

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