Climate and TEP Resource Portfolios – Emissions Reduction and Cumulative Carbon Budgets

Abstract

Project Overview

This report is a technical summary of Phase 2 of the TEP/UA Greenhouse Gas Emissions Reductions Targets project. We completed Phase 1 and published that report in Fall 2019 (Knudson et al., 2019). The Phase 1 report includes two elements. First, it provides an overview of the state of the climate and the implications for the U.S. Southwest. Second, it offers a preliminary review of utility practices for setting greenhouse gas emissions reductions targets. Phase 2 further explores emissions reductions guidelines for companies, the logic behind science-based targets for emissions reduction, and sector-specific practices consistent with targeted limits to warming. We expanded the analysis to include the role of discrete carbon budgets that set limits on carbon emissions based on specific warming targets (e.g., 1.5 C, 2 C, etc.). We evaluated TEP Integrated Resource Plan portfolio scenarios provided by TEP and informed by input from TEP’s Stakeholder Advisory Council. Our evaluation focused on 1) emissions reductions targets associated with current scientific guidance regarding general and sector-specific emissions reductions required to keep global warming under various targets, and 2) a calculation of the relationship between discrete carbon emissions budgets developed by TEP and specific warming targets (1.5 C, 2 C, etc.). For an overview of the TEP IRP process and the role of the Stakeholder Advisory Council, please refer to https://www.tep.com/resource-planning/.