Abstract: Pathways for limiting global warming to 1.5° and 2°C generally involve net-zero greenhouse gas (GHG) emissions economy-wide near mid-century and halving emissions over the next decade. Updated pledges by countries and companies around the 2021 United Nations climate conference reflect this sense of urgency. The updated US pledge to reduce net emissions 50 to 52% by 2030 would represent a tripling of the pace of historical reductions.

We report on a six-model intercomparison of potential actions to reach the US target of at least 50% GHG reductions by 2030. This analysis helps identify which findings are more robust or uncertain given different model structures and input assumptions. Models highlight the central roles of clean electricity and electrification, the large scale of deployment needed relative to historical levels and scenarios with only current policies, and a range of benefits from near-term action.

Abstract: 

The MIT Economic Projection and Policy Analysis (EPPA) model has been widely used in energy, land use, technology, and climate policy studies. Here we provide details of revisions that form the basis of EPPA7, the current version.

Key updates include: 1) using the latest Global Trade Analysis Project (GTAP-power) database as the core economic data for the world economy; 2) updating regional economic growth projections; 3) separating extant and vintage capital of the previously aggregated fossil generation; 4) using an innovative approach to calculate the costs of backstop (i.e., advanced) power generation options based on engineering data from the Energy Information Administration; 5) identifying base year biofuel output from existing sectors; and 6) re-parameterizing electric vehicles based on recent studies.

Our simulations demonstrate that with widespread mitigation policies worldwide, regions relying heavily on fossil fuel imports benefit from lower global fossil fuel prices when their domestic emissions targets are lenient, but the benefits dissipate when deeper emissions cuts are imposed domestically. We also provide an illustration how the model output can be used to calculate the net present values of unrealized fossil fuel production and stranded assets from idling coal power generation under various policy scenarios.