Develop emissions analysis module

[grgmiller]

In order to make the CEMS data more usable for analyzing GHG emission factors at the generator level, I am beginning work on pudl.analysis.emissions which will create a "cleaned" CEMS dataframe that will containing:

• operating_datetime_utc
• plant_id_eia
• generator_id
• gross_generation_mwh
• net_generation_mwh
• co2_mass_tons

This module will contain functions that:

• calculate gross_generation_mwh from gross_load_mw and operating_time_hours
• calculate parasitic loss factors / gross-to-net ratios to convert gross_generation_mwh to net_generation mwh
• fill missing co2_mass_tons data using heat_input_mmbtu and fuel type proportions calculated from bf_eia923
• using techniques similar to those used in the analysis.mcoe module, aggregate boiler-level data to generator-level data (after ensuring correct mapping of EPA unit_ids to EIA generator_ids using the crosswalk provided by the EPA)

I plan to use this as a starting point for the eGRID project.

Feedback/thoughts on this module are welcome. I am starting in my fork of pudl located at https://github.com/grgmiller/pudl.

[zaneselvans]

@TrentonBush You might want to get in touch with @grgmiller about the CEMS / RMI emissions work.