How to get carbon emission data by fuel(or input)

[JiahongGUO121]

Dear everyone,
I'm trying to run GCAM-CHINA and I want to get carbon emission data by fuel. Queries on CO2 emissions are “CO2 emissions by tech (excluding resource production)” and "CO2 emissions by subsector (excluding resource production)". I tried to write a new query based on these two queries, but it didn't work:

 <emissionsQueryBuilder title="CO2 emissions by fuel">
            <axis1 name="fuel">input</axis1>
            <axis2 name="Year">emissions</axis2>
            <xPath buildList="true" dataName="emissions" group="false" sumAll="false">*[@type = 'sector' ]/*[@type='subsector']/*[@type='technology']/*[@type='input']//
        CO2/emissions/node()</xPath>
            <comments/>
        </emissionsQueryBuilder>

How can I get this query correct? Any help is greatly appreciated.

[pkyle]

The problem logically is that CO2 emissions in the model are not calculated or reported by input. The calculation of CO2 emissions happens at the level of the technology, and it's based on the input-output coefficients and fuel carbon intensities of each input fuel, taking into consideration any carbon sequestration, whether through non-energy use (i.e. feedstocks) or CO2 capture and storage.
If you want to decompose the reported emissions by any technology into its input fuels, you will probably need to query the energy consumption by technology (inputs by tech), along with CO2 sequestration by technology, and use the model's assumptions regarding fuel carbon contents written out in Ccoef.xml and CO2 sequestration fractions (in various XML files under the tag remove-fraction), to replicate the model's calculations of CO2 emissions by technology.

[JiahongGUO121]

Thank you very much for your kind guidance! I will follow your advise and explore these xml files.

[837288251]

The problem logically is that CO2 emissions in the model are not calculated or reported by input. The calculation of CO2 emissions happens at the level of the technology, and it's based on the input-output coefficients and fuel carbon intensities of each input fuel, taking into consideration any carbon sequestration, whether through non-energy use (i.e. feedstocks) or CO2 capture and storage. If you want to decompose the reported emissions by any technology into its input fuels, you will probably need to query the energy consumption by technology (inputs by tech), along with CO2 sequestration by technology, and use the model's assumptions regarding fuel carbon contents written out in Ccoef.xml and CO2 sequestration fractions (in various XML files under the tag remove-fraction), to replicate the model's calculations of CO2 emissions by technology.

Hi, I'm also working on CO2 emission and found that the technology "electricity-coal(conv pul)" was not equal to energy consmption*Ccoef.As the following picture shows, in this version, energy consumption of "electricity-coal(conv pul)" was 5.236 in 2015 and CO2 emission of this technology was 386.297 in 2015. If I use the coefficient of "coal" in Ccoef.xml ,that will be 5.236×27.3=142.94, which is only a half of 386.297. How would this happen? Is there any difficience in calculation method? Thank you very much!

[pkyle]

The query elec gen by gen tech is a query of electricity output. You need coal input for this calculation, elec energy input by elec gen tech

[837288251]

The query elec gen by gen tech is a query of electricity output. You need coal input for this calculation, elec energy input by elec gen tech

Thank you！Recently I found that the query "inputs by tech" was also the input that the CO2 emission could be calculated out. The efficiency between the input and output can be changed in global technology database.

[JiahongGUO121]

Hi page!
I was looking at the XML file as you suggested, but the CO2 emissions from the feedstocks sector bothered me.

1. When the query is “CO2 emission by sector (excluding resource production)”, does GCAM not count CO2 emissions from chemical/construction feedstocks?

2. Why is the of refined liquids of chemical feedstock set to 1 in chemical.xml, while coal and gas is set to 0? Do the Settings here also affect CO2 emissions?

3. In another query “CO2 emission by sector (no bio)”, the CO2 emissions of chemical/construction feedstocks are negative. Is this due to oil credit? I checked your answer in this URL:Oil Credits and Bio Feedstock Limit #104, but I still not clear how GCAM calculated such negative emissions numbers?

Thank you in advance!

[pkyle]

Good questions! The reported CO2 emissions from the feedstocks sectors do contribute to regional CO2 emissions, though as you note all emissions are sourced from coal and gas feedstocks. The sequestration fractions that we assume are 100% for refined liquids, and 0% for coal and gas. These are obviously not true to the best estimates, but the convention follows what the CDIAC emissions inventory team did when compiling their emissions inventories. I believe the petroleum sequestration fraction should be more like 65%, for instance; not sure about gas and coal. This is covered in various EPA technical methods reports, in support of emission inventories. There are a number of complexities that go into this, including lifetimes (some non-energy uses result in CO2 during the same year; others some number of years later), specific products being made (e.g., organic chemicals contain carbon and tend to produced from petroleum feedstocks, whereas inorganic chemicals do not contain carbon and tend to be produced from natural gas), and inconsistent reporting practices. I believe the only country that reports a significant amount of coal non-energy use is China, but I suspect it's partly because they're reporting some portion of blast furnace feed as non energy use. While technically a non combustion reaction, and therefore “non-energy” use, the iron reduction chemical reactions do not sequester any carbon (it’s all turned into CO2). Also be aware that some of the non-energy uses take place within the ammonia sector, where we do not disaggregate energy and non-energy uses. Anyway you’re welcome to revise these fractions, which are in:

inst/extdata/energy/A*.nonenergy_Cseq

(3 separate files, for chemicals 325, construction 324, and other industry 32).
Regarding the negative emissions from construction feedstocks, this is from some portion of the asphalt being produced from biomass feedstocks. It's one of the model's sneaky pathways of BECCS!