Create core_eia176__yearly_liquefied_natural_gas_inventory

[MeadBarrel]

Overview

Closes #4695.

What problem does this address?

What did you change?

Documentation

Make sure to update relevant aspects of the documentation:

• Update the release notes: reference the PR and related issues.
• Update relevant Data Source jinja templates (see docs/data_sources/templates).
• Update relevant table or source description metadata (see src/metadata).
• Review and update any other aspects of the documentation that might be affected by this PR.

Testing

How did you make sure this worked? How can a reviewer verify this?

To-do list

• If updating analyses or data processing functions: make sure to update row count expectations in dbt tests.
• Run make pytest-coverage locally to ensure that the merge queue will accept your PR.
• Review the PR yourself and call out any questions or issues you have.
• For PRs that change the PUDL outputs significantly, run the full ETL locally and then run the data validations using dbt. If you can't run the ETL locally then run the build-deploy-pudl GitHub Action manually and ensure that it succeeds.

[e-belfer]

Happy to re-review this when you're ready, but this little table is looking close to done.

From looking at the reported values by year, it seems like lng_inventory_volume is the variable name from 2002-2010 and then lng_facility_volume is the variable name used from 2011-present. These do not overlap at all, so we should combine these two columns into one lng_facility_volume column. You could do something like:

df['lng_facility_volume'] = df['lng_facility_volume'].fillna(df['lng_inventory_volume'])

Once that's done, I think adding a facility_type categorical column with "lng_terminal" and "marine_terminal" would be a simple addition to make this table even skinnier.

[e-belfer]

We add the units to the end of the column name typically, so these should wind up being lng_facility_volume_mcf, etc.