US emission factors
The US Environment Protection Agency publishes the Emissions & Generation Resource Integrated Database (eGRID) every year. The eGRID data includes generation, emissions among other attributes for almost all power plants on the US territory. The dataset is available here.
To compute regional emission factors for the US, each power plant in the eGRID dataset was matched to the corresponding Electricity Maps zone. Emission factors for each plant in a zone are then aggregated to create the emissions factors per production mode per zone.
The methodology to compute the US direct emission factors is detailed in this following notebook: US_emission_factors.ipynb.
The datasets used in the process are available and are listed below:
- eGRID data 2020 (spreadsheet)
The figure below shows the difference between the US average lifecycle emission factors and the default lifecycle emission factors.
Figure 1: Comparison of US lifecycle emission factors and default lifecycle factors
Upstream emissions represent all lifecycle emissions that are not directly generated during the operation of power plants.
Production modes not expanded upon below see their upstream emissions computed as the difference between our default lifecycle and direct emission factors as specified in the Default emission factors page.
The coal upstream emissions are generated from the data that was aggregated for Oberschelp, Christopher, et al. "Global emission hotspots of coal power generation." Nature Sustainability 2.2 (2019): 113-121.
They provide a comprehensive dataset for worldwide upstream coal emissions.
Solar upstream emissions were computed using the INCER-ACV tool. Developed by the French Agency for Ecological Transition, it allows to compute lifecycle (and thus upstream) emission factors for photovoltaic solar based on average solar irradiance of a zone.
Direct biomass emissions are generally accounted as 0 (See [BEIS 2021]). We have therefore accounted reported emissions from power plants as upstream emissions.
- Thomas Gibon for helping Electricity Maps identify some of these key data sources and for validating the methodology
- Dave Jones and Ember for reviewing the methodology