En-ROADS is a System Dynamics model built in the Vensim modeling software. The model code is then translated into WebAssembly via the SD Everywhere tools built by Climate Interactive so that the model can run in a web browser. The En-ROADS web application and its user interface is built using the Svelte framework along with a number of other open source web development tools and packages.


En-ROADS is an extension of (and contains most of) the C-ROADS simulator, which focuses on international emission dynamics.


The model is an ordinary differential equation system, solved by Euler integration. No intertemporal or short-term equilibrium is assumed. In other words, En-ROADS is not an equilibrium model where technology development is driven by cost-optimal supply-demand balance. Instead, decisions about energy sources and intensities in the model are represented by simple heuristics with myopic expectations.


The model represents key processes in the energy system and its connections to climate, economy, and environment for a single, global region. Distinctions among regions are obviously important in the real world. However, this would considerably complicate the simple accounting framework of the model, particularly by introducing trade issues, rendering it less useful for rapid scenario experimentation. En-ROADS is calibrated to a suite of Integrated Assessment Models (IAMs). You can learn more about the structure, equations, data sources, calibration, and testing of En-ROADS in the En-ROADS Technical Reference.


The En-ROADS simulator is intended for interactive scenario exploration. It helps users to think about:

  • Dynamics of capital stock turnover

  • Growth, energy intensity, and carbon intensity (elements of the Kaya identity) as drivers of emissions

  • Implications of technological lock-in for particular technologies

  • Effective combinations of supply-side vs. demand-side, or technology-driven vs. incentive-driven, policies, as well as their side effects

  • The scale of socioeconomic and emissions changes required to meet climate goals