Carbon Capture, Allocation, Transportation, and Sequestration Module - NEMS Documentation
July 2025
Introduction
The Carbon Capture, Allocation, Transportation, and Sequestration (CCATS) module models the captured carbon dioxide (CO2) system within the National Energy Modeling System (NEMS). CCATS endogenously allocates and transports the projected supply of captured CO2 from NEMS modules to utilization and storage sites throughout the United States.
At its core, CCATS is an optimization model that minimizes various operation and investment costs for capturing, transporting, and sequestering or utilizing CO2. After applying policy incentives, the module determines the most cost-effective network flow of CO2 from supply sources to demand locations and projects the development of CO2 infrastructure for both transportation and saline storage until 2050.
CCATS was first introduced in NEMS for the Annual Energy Outlook 2025 (AEO2025) to better reflect the emerging market for captured carbon dioxide (CO2). Prior to the Inflation Reduction Act (IRA), policy incentives for carbon capture and storage were insufficient to support the development of carbon storage at scale. The module was designed to be flexible to incorporate future policies and to more accurately project potential long-term trends in U.S. energy markets. CCATS replaced the Capture, Transport, Utilization, Storage (CTUS) from prior AEOs.