The urgency of the climate crisis is leading many large energy consumers to consider how they can more accurately assess the impacts of various potential actions on grid decarbonization. This paper provides an overview of the ZEROgrid Impact Advisory Initiative’s collective findings on consequential impact and reliability assessments, their implications, and areas where further research is required. This consensus paper is intended for corporate practitioners and policymakers navigating policy, investment, and procurement decisions that affect grid decarbonization and reliability.

Areas of Consensus:

1. Defining impact. The true impact of any voluntary corporate action (or really any action) is the difference in total emissions between a world where the action was taken, versus one in which it wasn’t.
2. Components of impact. This impact is the sum of several different contributing effects, which must include the effects over the lifetime of the intervention — how an intervention changes the short-run operations of power plants, and how it changes the total supply of different power plants in the long run — to fully capture the impact of an action.
3. Estimates vs. true values. The field has a number of ways to produce estimates of this impact, but currently lacks — indeed may always lack — any generally accepted way to empirically verify estimates of structural change. Therefore, any approach that seeks to measure total impact has (potentially significant levels of) uncertainty.

Conclusions and Future Research:

In order to build on this work and continue to provide further actionable insights to companies and policymakers, IAI members intend to continue to explore questions such as:

• How can the outputs of various models be compared using the framework presented here, and what are their respective strengths and limitations (e.g., accessibility, uncertainty, and ability to estimate total and/or components of impact)?
• What insights can consequential impact assessments provide to inform and improve attributional frameworks such as annual matching, time-based procurement, and emissions-based procurement?
• Which actions are consistently higher impact and what ones are not?
• Across a range of different actions, models, methods, and authors, which statements are consistently supported and which vary based on the model or method?
• Even if it is not possible to fully quantify the uncertainty in these estimates, is it possible to at least bound that uncertainty so policymakers can have some idea of what is known and unknown?