REopt Lite Adds Custom Electricity Rates and an Integrated Critical Load Builder

March 6, 2019 | Contact media relations

Building owners and energy managers looking to evaluate renewable energy and storage economics for their site can use REopt Lite's custom utility rate tariff capabilities and an integrated critical load profile builder—new features that allow a more detailed energy analysis without leaving the tool.

The latest update to the National Renewable Energy Laboratory’s (NREL) REopt Lite web tool offers a wide range of existing or hypothetical utility rates and helps identify systems to sustain specific critical loads during a site outage.

A graph shows a user’s critical load profile based on REopt Lite tool inputs.

REopt Lite helps users build a list of critical equipment and create a daily emergency load profile to support resilience goals.

REopt Lite's extended custom electricity rate feature allows users to build their own detailed utility rates with energy and demand charges that vary by time of day and season. Users can still select rate tariffs from the Utility Rate Database, but this new capability also allows users to model rates not included in that database, such as international rates or hypothetical rates. The custom utility rate tariff feature enables analysis across a wider range of locations, as well as what-if analysis of potential future rates.

The critical load builder allows users to create a daily emergency load profile within REopt Lite by building a list of equipment that is critical at their site—along with wattage, quantity, daily operation hours, and annual operation months. The critical load builder is based on SolarResilient, a tool developed by Arup, under contract to the Department of the City and County of San Francisco, with funding from the U.S. Department of Energy (DOE).

The latest REopt Lite updates are also included in the REopt Lite application programming interface (API). The REopt Lite API lets users and software developers programmatically interface with the REopt Lite web tool, evaluate multiple sites and perform sensitivity analyses in an efficient manner, and integrate REopt Lite capabilities into other tools.

REopt Lite's development is supported by DOE's Office of Energy Efficiency and Renewable Energy Federal Energy Management Program, and in part by The Kresge Foundation through Clean Energy Group's Resilient Power Project.

REopt Lite is a publicly available web version of the more comprehensive REopt model, a techno-economic decision support platform that evaluates a range of renewable and conventional energy technologies and performs complex grid outage modeling, among other capabilities. Learn more about NREL's REopt analysis services at

Tags: Buildings,Photovoltaics,Energy Analysis,Technology Deployment,Manufacturing,Energy Systems Integration,Wind