Renewable Certificate Tracking Zones

[trevorb1]

PR #614 introduced Renewable Energy Certificates (REC) when implementing the RPS constraint. My question is the regions included when calculating the RECs.

I am def not an expert on RECs, but I understood the EPA regulations to be applied to the entire trading regions (for example WREGIS); regardless if the state within the trading region has a RPS. But I believe we calculate the demand based at a state level (rather than trading zone level).

https://github.com/PyPSA/pypsa-usa/blob/8befa84b0b1d9c492d87c763a26e27198195f624/workflow/scripts/opts/policy.py#L289-L314

For example, consider that if the two RPS are configured as given below:

planning_horizon	region	carrier	pct
2030	CA	onwind, solar, offwind_floating, geothermal	0.50
2030	OR	onwind, solar, offwind_floating, geothermal	0.50

I think the current functionality is:

(Gen_CA renewables) + (Gen_OR renewables) >= (Load_CA * 0.50) + (Load_OR * 0.50)

But it seems like based on the EPA literature, it should be:

(Gen_CA renewables) + (Gen_OR renewables) + (Gen_WA renewables) + (Gen_AZ renewables) + (Gen_NV renewables) + [remainder of states in WREGIS] >= (Load_CA * 0.50) + (Load_OR * 0.50)

@ktehranchi any thoughts? I may just be misunderstanding either the implementation logic and/or the EPA rules! I also do get if we balance at a trading level, that comes with its own issues. For example, having to track RECs by carrier, or how to balance if you run models with only a subset of regions, ect.

[trevorb1]

I guess, maybe tangentially related, the RPS is applied to the end-use demand rather than the energy generated? I guess I understood RPS to apply to the electricity supply rather than demand?

[ktehranchi]

I think your interpretation is correct and my implementation will leave out generation from states which don’t have an active RPS/CES standard… in the WECC it means ID & WY would be left out for WREGIS since all other states have RPS/CES. Only other region impacted by this would the the Southeast.

Feel free to fix or I can get to this first week of Sept

[trevorb1]

Thanks for the clarification! I think its more than just ID, WY and south east, tho. For example, in WECC, Montana has repealed RPS I believe, and PJM-GATS is missing WV and KT. Moreover, places like Kansas (for NAR) who have expired RPS are not guaranteed to have aligned planning horizons in the the reeds files.

Not urgent for me! Just something to flag I guess.