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Future Automotive Systems Technology Simulator


FASTSim icon

The FASTSim simulation tool evaluates the impact of technology improvements on efficiency, performance, cost, and battery life in conventional and advanced vehicles.

Developed by NREL, the Future Automotive Systems Technology Simulator (FASTSim) evaluates the impact of technology improvements on efficiency, performance, cost, and battery life in conventional vehicles, hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and all-electric vehicles (EVs).

FASTSim answers questions like:

  • Which battery sizes are most cost effective for a PHEV or EV?
  • At what battery prices do PHEVs and EVs become cost effective?
  • On average, how much fuel does a PHEV with a 30-mile electric range save?
  • How much fuel savings does an HEV provide for a given drive cycle?
  • How do lifetime costs and petroleum use compare for conventional vehicles, HEVs, PHEVs, and EVs?


FASTSim incorporates the following factors:

  • Speed vs. time simulation (drag, acceleration, ascent, and rolling resistance)
  • Powertrain components (engine, motor, battery, and auxiliary loads)
  • Regenerative braking
  • Energy management strategies
  • Battery life estimates
  • Cost estimates
  • Distribution of driving distances
  • Validation of important outputs (efficiency, performance, battery life, and cost).

Download FASTSim

Available as an Excel file for download, this easy-to-use simulation tool features a user-friendly interface for inputting data such as engine power, battery power, and vehicle weight. FASTSim takes about three seconds to estimate vehicle fuel economy, performance, battery life, and cost.

Download the beta 2 version of FASTSim

The beta 2 version of FASTSim works with Microsoft Excel 2007 and 2010. This version resolves an Excel 2010 problem that causes hidden graphical interface controls to disappear when saving and closing. While Microsoft Support provides a hotfix to remedy the problem associated with the beta 1 version, the beta 2 version works properly without the hotfix.

While NREL does not provide technical support for FASTSim, we welcome your feedback on the tool. Please email your feedback or report any problems to

More Information

For more information about FASTSim, subscribe for periodic email updates or refer to this technical paper—FASTSim: A Model to Estimate Vehicle Efficiency, Cost, and Performance.

Some of the publications listed on the Transportation Secure Data Center Data Application Examples webpage provide examples of how FASTSim's rapid simulation capabilities have been used to evaluate real-world vehicle efficiency over myriad driving trajectories.