Emissions from fuel cells

[grgmiller]

The eGRID2020 technical guide notes:

The CO2 emissions for units with a fuel cell prime mover are also assumed to be zero.

However, as noted by several sources, fuel cells not not necessarily have zero emissions if they use natural gas as a fuel.

• This reporting on Bloom fuel cells indicates an emission rate of 773-884 lbCO2/MWh
• This EPA report indicates fuel cell emissions between 734 and 1131 lbCO2/MWh for uncontolled emissions, and that certain types of fuel cells have non-negligable NOx and SOx emissions (see table 6-5)

Currently our data pipeline does not set fuel cell emissions to zero, but uses the default natural gas combustion emission factor to calculate emissions - it is unclear if this is appropriate.

To do:

• [ ] Identify appropriate default emission factors for natural gas fuel cells.
• [ ] Integrate these emission factors into the pipeline

[grgmiller]

Our NOx and SO2 calculation methodology implemented in https://github.com/singularity-energy/hourly-egrid/pull/152 currently assumed zero NOx and SO2 emissions from natural gas consuming fuel cells. We should research and refine this assumption.