PRAS: Probabilistic Resource Adequacy Suite

NREL's Probabilistic Resource Adequacy Suite (PRAS) provides an open-source, research-oriented collection of tools for analyzing the resource adequacy of bulk power systems.

Resource adequacy describes a power system's ability to meet demand for electricity. PRAS simulates power system operations under a range of operating conditions to study the risk of failing to meet demand—due to a lack of electricity supply or deliverability— and identify the time periods and regions in which that risk occurs.

Energy shortfall risk distribution by region, season, and time of day, for a contrived future North American power system as modeled using PRAS.

PRAS performs low-fidelity, high-speed simulations of multi-region power system operations, considering hundreds of thousands of years of unplanned resource outages to quantify the risk and potential nature of energy supply shortfalls in probabilistic terms. PRAS can be used to calculate the capacity credit of variable and energy-limited resources such as wind, solar, and storage and may be complemented with higher-fidelity, deterministic production cost modeling for more detailed operational insights. The PRAS ecosystem includes integrations with other NREL tools, including the Regional Energy Deployment System, the Resource Planning Model, and the Scalable Integrated Infrastructure Planning model.

Download Model from GitHub

The GitHub repository includes the PRAS model code, instructions, and more.


Probabilistic Resource Adequacy Suite (PRAS) v0.6 Model Documentation (2021)

Example Analysis

As part of two studies, PRAS modeled the 7-year average capacity factor and the estimated capacity credit for 20-km x 20-km grids in the United States. Higher capacity credits indicate a higher contribution of wind's capacity to the total power system. Download data.

Featured Publications

Comparing Capacity Credit Calculations for Wind: A Case Study in Texas, NREL Technical Report (2021)

A Systematic Evaluation of Wind's Capacity Credit in the Western United StatesWind Energy (2021)

The Los Angeles 100% Renewable Energy Study, Chapter 6: Renewable Energy Investments and Operations, NREL Technical Report (2021)

Managing Solar Photovoltaic Integration in the Western United States: Resource Adequacy Considerations, NREL Technical Report (2021)

The North American Renewable Integration Study: A U.S. Perspective, NREL Technical Report (2021)

Preparing Distribution Utilities for the Future – Evolving Customer Consumption in Renewable Rich Grids: A Novel Analytical Framework, NREL Technical Report (2021)

Adapting Existing Energy Planning, Simulation, and Operational Models for Resilience Analysis, NREL Technical Report (2020)

The Potential Impact of Offshore Wind Energy on a Future Power System in the US Northeast, NREL Technical Report (2020)

Evaluating Resource Adequacy Impacts on Energy Market Prices Across Wind and Solar Penetration LevelsThe Electricity Journal (2019)


Gord Stephen

Gord Stephen

Grid Systems Research Engineer