Sequestration Inputs for RNG Upgrader Emissions

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1 month 6 days ago #558 by fionaadsilva
Hello,

I am working on a Manure-to-RNG anaerobic digester project where the exhaust stream from the biogas upgrader gets captured and sequestered. The natural gas combustion emissions do not get captured.

I am currently unsure whether cell AZ19 in the Sequestration tab should be the fraction of captured upgrading emissions over the total released CO2 from the upgrader or the fraction of captured upgrading emissions over the total released CO2 from the entire process. Could you please clarify?

Additionally, the emissions from the upgrader are biogenic CO2. Does the model consider this and distinguish this from non-biogenic CO2 in the results?

Thank you

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1 month 5 days ago #559 by doconnor
The assumption is that just the process CO2 is captured. However, since the ratio of CO2 to CH4 can vary with the feedstock and the digestor what you really need to do is to adjust the AZ19 so that you get the correct value in AZ30, the CO2 sequestered per GJ of RNG produced..

For sequestration, it doesn't matter if the CO2 is fossil or biogenic, it is still CO2 that is removed from the atmosphere.

Regards
Don O'Connor

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1 month 3 days ago #560 by fionaadsilva
Replied by fionaadsilva on topic Sequestration Inputs for RNG Upgrader Emissions
Hi Don,

Thank you for your response. I understand cell AZ19 can be adjusted to reflect the value in AZ30, but cell AZ30 is not used in the Upstream Results HHV and BC LCFS results. Could you please clarify?

Thank you,
Fiona

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1 month 3 days ago #561 by doconnor
Fiona

It is true that AZ30 doesn't go anywhere but the input cell Equip Emiss Factors CA22 does flow to CA25 which does go the Upstream Emissions sheet.

Regards
Don O'Connor

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