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REopt Lite Software Update History

NREL updates the REopt Lite™ web tool on a regular basis. Review REopt Lite's software update history below.

February 2021: Combined Heat and Power, Third-Party Financing, Enhanced Utility-Rate Modeling, and Scenario Comparisons

This version of REopt Lite allows users to model and size combined heat and power (CHP) systems alone, compare CHP to renewable energy and battery storage options, or leverage all three of these systems in a complementary manner for energy efficiency and resiliency. The U.S. Department of Energy's (DOE's) Advanced Manufacturing Office (AMO) funded the REopt Lite CHP project, building on the existing REopt Lite model funded by DOE's Federal Energy Management Program (FEMP). Along with the AMO-funded CHP capabilities, REopt Lite released several new FEMP-funded modeling capabilities for renewable energy projects: third-party financing, enhanced utility-rate modeling features, and comparison of different scenario results.

February 2020: Open Source Software

REopt Lite Open Source lets users explore and customize the code and work with NREL to implement new REopt Lite features. Access the REopt Lite GitHub repositories.

December 2019: Downloadable Results Report

Version 1.5.1 of REopt Lite includes a new downloadable results report that allows users to download a PDF version of a saved site evaluation.

October 2019: Resilience Modeling, Diesel Generator Sizing, Load Profile Dashboard, Utility Rate Help, International Guidelines, and Updated Cost Assumptions

Version 1.5 of REopt Lite includes a new diesel generator optimization feature and new resilience graphics that show the expected performance of a system over a range of outages starting at different times of the year. Users are now guided to the most likely utility rates based on their location, load, and the utility’s most common rates. A new load profile dashboard allows users to upload and save custom typical and critical load profiles, and new international guidelines give users tips for using REopt Lite at international sites. Default values for technology costs have been updated based on the latest market reports.

April 2019: PVWatts and Solar Resource Data Set Upgrade

Version 1.4.1 of REopt Lite includes updated solar photovoltaic (PV) system performance data with an upgrade to PVWatts 6, which incorporates additional international solar resources from the National Solar Radiation Database (NSRDB) data set.

March 2019: Custom Hourly Rate Tariffs and Integrated Critical Load Builder

Version 1.4 of REopt Lite includes custom hourly utility rate tariff capabilities and an integrated critical load profile builder, for a more detailed energy analysis without leaving the tool. The latest update includes a wide range of existing or hypothetical utility rates and helps identify systems that can sustain specific critical loads during a site outage.

November 2018: Wind Module, Custom Monthly Rate Tariffs, Critical Load Builder, and User Dashboard

Version 1.3 of REopt Lite includes a new wind optimization module, custom monthly utility rate tariffs, a link to the SolarResilient critical load builder, and a new user dashboard. These features allow users to evaluate the economic viability of distributed wind alongside solar PV and battery storage, and further customize cost savings and resilience analyses. The user dashboard lets users log in, save their optimization results, and view previous runs.

June 2018: Enhanced Resilience Features

Version 1.2 of REopt Lite includes enhanced resilience analysis capabilities that allow building owners and energy managers to size PV and storage systems to meet a specified outage duration, and compare systems sized for optimum savings to systems sized for resilience. Users can also explore the impact of microgrid upgrade costs and avoided outage costs on project economics.

March 2018: Application Programming Interface

Version 1.1 of REopt Lite includes a new application programming interface (API) that lets users and software developers programmatically interface with the REopt Lite web tool. The API can be used to evaluate multiple sites and perform sensitivity analyses in an efficient manner, and integrate REopt Lite capabilities into other tools. Access the API.

In addition to the API release, REopt Lite developers added a downloadable dispatch strategy and additional utility rates to the web tool.

September 2017: REopt Lite's Initial Release

Version 1.0 of the REopt Lite web tool, deployed on September 29, 2017, helps building owners evaluate the economics of grid-connected PV and battery storage at commercial sites. It identifies the optimal PV system size and battery dispatch strategy to minimize the life cycle cost of energy at a specific site, and estimates the amount of time a PV and battery system can sustain the site's critical load during a grid outage. 

For the first time, REopt Lite provides public access to a subset of NREL’s comprehensive REopt model, and allows users to run their own site-specific, optimized, and integrated renewable energy decision analysis in order to accelerate renewable energy and storage project development and deployment. 

Future Development Plans

Learn more about future software development plans for the REopt Lite web tool.