REGEN

The Regional Economy, Greenhouse Gas, and Energy (REGEN) model is an energy-economy model developed and maintained by EPRI’s Energy Systems and Climate Analysis (ESCA) group. The model provides a customizable platform for policy analysis, technology assessment, and strategy that is informed by decades of EPRI research on energy modeling and technology analysis.

REGEN links a detailed electric sector capacity planning and fuels supply model with representations of demand in buildings, transport, and industry. The model jointly optimizes regional investments in electricity generation and energy storage, system dispatch, transmission, and non-electric fuels supply, which includes high temporal resolution and chronology to better characterize the economic incentives of variable renewables, energy storage, and dispatchable generation. The end-use models represent trade-offs between end-use technologies and fuels for a wide range of disaggregated sectors and activities with economy-wide coverage and include structural detail across several dimensions relevant for fuel and technology choice, such as building size, type, and vintage, climate zone and location, and vehicle ownership and driving intensity.

Download Introductory slides on REGEN (last updated in April 2025).

US-REGEN

US-REGEN was launched in 2011 in collaboration with 13 U.S. utilities to explore the impacts of high renewable deployment and decarbonization policies in the U.S. An end-use model was added in 2016 and a representation of fuel supply was added in 2020. US-REGEN can flexibly represent individual states and any aggregation of those states. US-REGEN has been widely used to evaluate U.S. climate policy proposals, technological pathways to deep decarbonization of the electric and energy sectors, and affordability and distributional impacts of energy transitions.

Download Introductory slides on REGEN (last updated in April 2025).

Access the open-source version of US-REGEN on GitHub

Current Full Documentation List

Contact:

• Geoff Blanford gblanford@epri.com
• Chris DeLyser Roney croney@epri.com

Highlighted Analysis

• Climate Policy Reform Options in 2025

• Powering Data Centers: U.S. Energy System and Emissions Impacts of Growing Loads

• Impacts of EPA’s finalized power plant greenhouse gas standards

• A multi-model study to inform the United States’ 2035 NDC

• Net-Zero 2050: Sensitivity Analysis and Updated Scenarios

• Representation of Geothermal Resources and Technologies in EPRI’s US-REGEN Model: Guidelines for Enhancing Geothermal Integration in Capacity Expansion Models

• LCRI Net-Zero 2050: U.S. Economy-Wide Deep Decarbonization Scenario Analysis

• The role of natural gas in reaching net-zero emissions in the electric sector | Nature Communications

• Electrification Scenarios for New York’s Energy Future (epri.com)

• Air Quality Implications of an Energy Scenario for California Using High Levels of Electrification | California Energy Commission

Methodology

• Merrick, J., J. Bistline, and G. Blanford (2024). On Representation of Energy Storage in Electricity Planning Models. Energy Economics, 136: 107675.

• Analysis of Foresight in Long-Term Energy System Models, EPRI Report 3002021161, December 2021

• Bistline, J., C. Roney, D. McCollum, and G. Blanford. Deep Decarbonization Impacts on Electric Load Shapes and Peak Demand. Environmental Research Letters, 16(9):094054, October 2021.

• Bistline, J.E., G. J. Blanford, T Mai, J Merrick. Modeling Variable Renewable Energy and Storage in the Power Sector. Energy Policy. 156:112424, September 2021,

• Bistline, J.E. The Importance of Temporal Resolution in Modeling Deep Decarbonization of the Electric Power Sector. Environmental Research Letters, 16:084005, July 2021,

• Bistline, J.E. Variability in Deeply Decarbonized Electricity Systems. Environmental Science & Technology. 55:9:5629-5635. April 2021.

• Geoff Blanford, James Merrick, John Bistline, and David Young (2018): “Simulating Annual Variation in Load, Wind, and Solar by Representative Hour Selection” (The Energy Journal)

Canada-REGEN

Canada-REGEN was launched in 2020 with support from EPRI Technology Innovation and represents both Canadian provinces and US states to capture the strong energy ties between the two countries. The current model includes a detailed capacity expansion model of the electric sector and an energy end-use model. Canada-REGEN can flexibly represent individual states and provinces and any aggregation of those states and provinces. A fuel supply model is under development in partnership with National Resources Canada.

Download Introductory slides on REGEN (last updated in April 2025).

Contact:

• Chris DeLyser Roney cdroney@epri.com
• Francisco Ralston Fonseca ralstonfonseca@epri.com

Canada REGEN Model Documentation

Highlighted Analysis

• Advanced Reactors Global Market Outlook and Economic Assessment: United States and Canada AR Economic Assessment Study

• Insights for Canadian electricity generation planning from an integrated assessment model: Should we be more cautious about hydropower cost overruns?

• Canadian National Electrification Assessment: Electrification Opportunities for Canada’s Energy Future EPRI Report 3002021160, September 2021

• Canadian National Electrification Assessment: Electrification Opportunities for Canada’s Energy Future (French Translation)

• Estimating Power Sector Leakage Risks and Provincial Impacts of Canadian Carbon Pricing Environmental and Resource Economics, 76, 91-118, April 2020

Japan-REGEN

Japan-REGEN was first completed in 2026 in collaboration with five Japanese energy utilities with co-funding from EPRI’s Low Carbon Resources Initiative (LCRI). Japan-REGEN represents all energy use and supply in Japan with a special focus on fuel import opportunities.

Download Introductory slides on REGEN (last updated in April 2025).

Documentation [limited access]