Add option for historical demand data from FERC 714 via PUDL

[ktehranchi]

Feature Request

I noticed on PUDL's website they perform some nice data preparation for historical state level demand:

WIth the EIA IDs, we link the hourly electricity demand to a particular georgraphic region at the county level, because utilities and balancing authorities report their service territories in core_eia861__yearly_service_territory, and from that information we can estimate historical hourly electricity demand by state.

This matching of BAs to County FIPs would be really useful in backcasting since an issue with my old backcasting data is in the alignment of BA's to GIS data. In this data the State shapes are distinct/non-changing.

• [ ] Add retrieve parquet for FERC714 data in the retrieve_pudl.py script for rule retrieve_pudl
• [ ] Add new option in build_demand.py

Additional Info

Example of pulling this data: https://github.com/catalyst-cooperative/pudl-examples/blob/main/02-state-hourly-electricity-demand.ipynb