Residual electricity mix

[dt-woods]

This pull request is to incorporate residual mix processes and product systems into the ElectricityLCI (NETL-RIC#276) using methods described in Davis et al. (2025).¹ The proposed change adds five new configurable parameters:

Name	Type	Description
add_residual_mix	bool	Whether to include residual electricity mix processes in JSON-LD.
output_residual_mix	bool	Whether to save the residual mix data as CSV in output folder.
add_rem_product_systems	bool	Whether to create "at user; residual consumption mix" product systems.
rem_weight_method	str	The state-to-balancing authority weighting method (e.g., by facility 'count').
neg_rem_method	str	The method to deal with negative renewable electricity generation (e.g., if REC sales in a BA are greater than renewable electricity generation); choose either to 'zero' excess or 'keep' excess and attempt to subtract if vague fuel categories (e.g., MIXED or OTHER) exist.

and six new global parameters introduced to globals.py:

Name	Type	Description
GREEN_E	list	Green or renewable energy categories for residual mixes.
OVERFLOW_E	list	Non-green fuels that can lend overflow electricity for res. mixes.
REM_WEIGHT_METHODS	list	State-level REC sales to Balancing authority weighting methods.
NEG_REM_METHODS	list	Accounting methods for negative renewable generation for REM.
NREL_REC_YEAR	int	See https://www.nrel.gov/analysis/renewable-power for pub years.
NREL_REC_URL	str	NREL voluntary renewable power procurement data sheet URL.

See __doc__ string in new residual_grid_mix.py module for explanation of the residual grid mix method. Only one weighting method is employed (i.e., the facility 'county' method). The add_residual_mixes method is added to the run_post_processes method in __init__.py, which only triggers new residual process creation if configured within the YAML. Residual processes take advantage of the existing _process method in olca_jsonld_write.py and are assigned UUIDs based on the new process name (see _make_residual_process_name). Two additional helper functions (i.e., _make_rem_gen_process and _make_rem_con_process) support the creation of "Electricity; at grid; residual generation mix", "Electricity; at grid; residual consumption mix", and "Electricity; at user; consumption mix" processes for each region.

If the user selects "add_rem_product_system" in the YAML, the "at user; residual consumption mix" processes are converted to product systems using the default providers.

If the user selects, "output_residual_mix", a CSV file is located in the electricitylci/output data store to show the original fuel-based generation (in MWh) and ratio along with the new non-REC generation and ratio.

This method was successfully tested on "ELCI_2023" configuration, producing residual processes and product systems on macOS 14 using Python 3.12 and developer version of fedelemflowlist (from KeyLogicLCA's forked repository), esupy (0.4.2), and StEWI (1.2.0).

Footnotes

1. Tyler W. Davis, Matthew Jamieson, Becca Rosen, Joseph Chou, elci_to_rem, 1/21/2025, https://edx.netl.doe.gov/dataset/elci_to_rem, DOI: 10.18141/2503966. ↩

[frankhanna94]

I made a minor change in model_config.py for error handling if 'output_residual_mix' = True but 'add_residual_mix' = False