Renewable Natural Gas

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2 years 11 months ago #62 by doconnor
Replied by doconnor on topic Renewable Natural Gas
Kenny

There is typically some methane lost from the digestor itself and there can be some methane from the gas cleanup system. In the model this is the 190 g methane is the rate per GJ of RNG produced. One GJ of NG weighs about 19 kg, so 1% of that is 190.
If you want o adjust this value I would do it in cell BR13.

Regards

Don O'Connor

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6 months 1 week ago #334 by mdebrock
Replied by mdebrock on topic Renewable Natural Gas
Hello,

I am working on an RNG pathway and found this post thread very helpful. Thanks for the information already provided.

One remaining question I have is about finished fuel transport distance. I noticed you did not list it as an input in the above response, and the default input is 1 km by pipeline.

For an application where the RNG is produced and injected into the grid in one region and low carbon fuel credits claimed in another, I have been erring on the conservative side and entering the distance between the two locations (I know that physically this is conservative as no gas actually travels that far.) However, when I do things that way, I get a very large adjustment for fuel distribution emissions - almost as large as if I assume shipment by rail. The other issue I see with modeling this way is that my entire transport energy calculation is stuck using the originating region electrical generation defaults, despite the fact that the pipeline would span multiple regions.

Is the intention in the RNG pathway to only account for the pipeline distance to the grid injection point, hence the low default value? Or is there a different set of assumptions you would recommend?

Thanks!

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6 months 1 week ago #335 by doconnor
Replied by doconnor on topic Renewable Natural Gas
The long distance transport of natural gas done using mostly gas turbines and not electric motors. This is not how the RNG pathway has been set up.

I can only suggest that you take the value from the NG pathway. The gas transmission emissions can be found in Cell DN 12 on the upstream emissions sheet. The distance that this value is calculated from Cells BA 325 to 367, depending on the region that the model is set for. If you override the calculated value with your actual value then the emissions will be in DN12.

Regards
Don O'Connor

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4 months 7 hours ago #353 by jnenviro
Replied by jnenviro on topic Renewable Natural Gas
Hello Don,

Thank you for all the information already provided in this post. On this topic, I was wondering what differences are considered between the LFG -> RNG fuel pathway vs other RNG pathways in the model (e.g., from AD or Organic Waste) that have a negative 'emissions displaced' value.

Does the LFG -> RNG pathway consider CO2e emissions avoided by gas capture of LFG? Or is that component not included in the pathway scope/covered in other RNG pathways.

Thank you in advance.

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3 months 4 weeks ago #354 by doconnor
Replied by doconnor on topic Renewable Natural Gas
For RNG purposes, it seems to generally accepted that there are no avoided emissions when landfill gas is captured. The rational appears to be that the raw gas was being collected and flared prior to collection and upgrading.

This has been the CARB assumption and it is also applied in the BC LCFS program.

I know that some offset protocols provide credits for LFG capture or a portion of the gas captured.

This is a regulatory issue more than an LCA issue.

Regards
Don O'Connor

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3 months 1 week ago #355 by pilar.canavosio
Replied by pilar.canavosio on topic Renewable Natural Gas
Hi Don,

Does the AD pathway apply to any livestock manure, or is it limited to dairy and swine like California?

Thanks!

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3 months 1 week ago #356 by doconnor
Replied by doconnor on topic Renewable Natural Gas
The pathway can be used for any manure but the avoided emissions are different for the different kinds of manure.

The next version will have multiple options for the type of manure with different methane avoidance rates.

If you are looking for a source for the data I would suggest that you look at the common reporting forms (CRF) that accompany the NIR reports that countries file with the UNFCCC.

Regards
Don O'Connor

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3 months 1 week ago #357 by pilar.canavosio
Replied by pilar.canavosio on topic Renewable Natural Gas
This is very helpful - thank you! When do you expect the next version to come out?

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3 months 1 week ago #360 by doconnor
Replied by doconnor on topic Renewable Natural Gas
We are working towards June or July.
Don O'Connor

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