Nonbaseload emission rates

[grgmiller]

We do not currently calculate nonbaseload emission rates, which are a type of marginal emission factor estimate.

In eGRID, nonbaseload emission rates are calculated based on the plant-level capacity factor.

All generation and emissions at plants with a low capacity factor (less than 0.2) are considered nonbaseload and are assigned a nonbaseload factor of 1. Plants with a capacity factor greater than 0.8 are considered baseload and are assigned a nonbaseload factor of 0. For plants with a capacity factor between 0.2 and 0.8, we use a linear relationship to determine the percent of generation and emissions that is nonbaseload:
Nonbaseload_Factor = -5/3 * (Capacity_Factor) + 4/3

It is unclear whether nonbaseload factors would make sense at the hourly resolution or if an alternate methodology would need to be developed. We could consider publishing monthly and annual resolution nonbaseload factors even if hourly factors do not make sense.

This could also be an opportunity to consider whether the nonbaseload methodology could be improved.

If we publish these, they should probably be separated as a different use case in results, such as results/marginal emissions

[grgmiller]

This paper suggests that annual average marginal factors (like non-baseload rates) actually may do reasonably well at approximating the emissions impact of demand-side interventions in the short run