Cambium data sets contain hourly emission, cost, and operational data for modeled futures of the U.S. electric sector with metrics designed to be useful for long-term decision-making.

Cambium was built to expand the metrics reported in NREL’s Standard Scenarios—an annually released set of projections of how the U.S. electric sector could evolve across a suite of different potential futures, looking ahead through 2050.

Long-Run Marginal Emission Rates

A long-run marginal emission rate is the rate of emissions that would be either induced or avoided by a long-term (i.e., more than several years) change in electrical demand, incorporating both the operational and structural consequences of the change. It is therefore distinct from the more commonly known short-run marginal, which treats grid assets as fixed.

Cambium data sets contain long-run marginal emission rate estimates for the contiguous United States. View and download the workbooks containing this metric and guidance on its use.

Screenshot of the Cambium data sets depicting an example long-run marginal CO2 emission rate pattern (kg/MWh) for the Contiguous United States, from the mid-case of the 2020 Standard Scenarios data set. The data is arranged into a heatmap format depicting number of hours in a day and the months in a year.
An example long-run marginal CO2 emission rate pattern (kg/MWh) for the contiguous United States from the mid-case scenario of the 2020 Standard Scenarios data set.

Access the Full Data Sets

Beyond long-run marginal emission rates, Cambium databases include other emission, cost, and operational metrics. The full data sets can be viewed and downloaded via the Cambium Viewer.

Screenshot of the interface of the Cambium Viewer, which includes four sections of interactive data in map and chart formats.

Limitations of Modeled Data

Cambium relies on models, which are necessarily simplifications of reality. The data produced by those models therefore deviate from reality to some degree. 

We strongly encourage users to critically evaluate the suitability of Cambium metrics for new analyses by reviewing existing literature and comparing Cambium data against empirical data where possible. To aid in this effort, we have provided modeled data for 2018 in the mid-case of the 2020 Standard Scenarios data release—available through the viewer—so that users can compare empirical market and operational data with the data provided in Cambium databases. Cambium data is not sufficiently accurate to be used for every purpose and should be assessed with a critical eye.

See Section 2 of the Cambium documentation for a detailed discussion of the limitations of the models underlying Cambium databases.


Forward-Looking Emissions Factors for Electric-Sector Planning

Image of a scatter plot graph depicting three common types of emission metrics compared to a diagonal parity line that indicates a well-performing metric.

Released March 2022,  the research article Planning for the Evolution of the Electric Grid With a Long-Run Marginal Emission Rate characterizes how well three common types of emissions factors can anticipate the emissions impacts of electric-sector interventions.  

The research finds that a forward-looking long-run marginal emission rate—which incorporates both the operational and structural consequences of an intervention—can out-perform two other common emissions factors. 

Journal Article: Planning for the Evolution of the Electric Grid with a Long-Run Marginal Emission Rate

Informational Webinar: Recording and presentation slides 

Related Publications 

Long-Run Marginal Emission Rates for Electricity, NREL Data Workbook (2021)

Cambium Documentation: Version 2021, NREL Technical Report (2021)

2021 Standard Scenarios Report: A U.S. Electricity Sector Outlook, NREL Technical Report (2021)

Integrating Cambium Marginal Costs into Electric-Sector Decisions, LBNL Technical Report (2021)

Pieter Gagnon

Senior Energy Systems Researcher