investigate difference in net get from generation_eia923 vs generation_fuel_eia923 tables

[cmgosnell]

gen table = generation_eia923 gen_fuel = generation_fuel_eia923

I assume this is all a vestige of reporting requirements.

• is gf always bigger? It is nearly always bigger.
  • when both tables are grouped at the plant/year level and merged together, the net gen in the gen_fuel table is larger or = in 87% of the records
  • 85% of the "missing" net gen (net gen that doesn't show up in in the gen table) is from plants that just don't show up in the gen table at all
• what is the scale of the difference?
  • 58% of the net gen reported in the gen_fuel is reported in the gen table
  • About 9% of plants have records which both have data in both tables and have a non-zero difference between the net gen.
• does it change over time?
  • It looks like it gets much cleaner after 2014 (i know, i know this graph is very ugly) stacked version:
• how often are the missing gens different PMs?
  • % of plants w/ gen v gen_fuel diff that have >1 prime mover: 91.39%
  • % of plants for which the generators missing from the gen table are all only one prime_move_code: 92.07%

[zaneselvans]

Have you made a plot of the annual ratio of generation reported in one table vs the other? Or even the monthly ratio, since these numbers are reported monthly? Like does it go to ~1.0 in 2014 when the combustion turbines start reporting?

[cmgosnell]

It is kinda hard to see in one graph:

But here they are broken out by these chunks of time:

It doesn't entirely go to zero post-2014, but more is less.

[zaneselvans]

I was thinking just a line plot, with time on the x axis, and ratio on the y axis.

[cmgosnell]

(I don't have a few years of old data in my db right now for some reason)

[zaneselvans]

Okay great, so it seems like the overwhelming majority of the issue here is the lack of combustion turbine reporting prior to May 2014.

[cmgosnell]

Hm.. well, no. That was only the plants which had some reporting to the gen table. I remade it w/ a note.. and made the second w/ all of the missing net gen. Maybe it is going up over these last few years due to more gas on the system?