Skip navigation to main content.
NREL - National Renewable Energy Laboratory
About NRELEnergy AnalysisScience and TechnologyTechnology TransferTechnology DeploymentEnergy Systems Integration

Future Automotive Systems Technology Simulator

FASTSim icon

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

NREL developed the Future Automotive Systems Technology Simulator (FASTSim) to evaluate the impact of technology improvements on vehicle 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, which has been tested in Microsoft Excel 2007 and 2010. The beta 2 version of FASTSim 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.

Subscribe for periodic email updates.

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