Transmission Integration

The goal of NREL's transmission integration research is to tackle the challenges of integrating renewables and other technologies into the bulk-power system while maintaining safe, efficient, and cost-effective grids.

Photo of transmission lines and wind turbines.

NREL works with electric utilities, energy policymakers, and other industry partners to integrate large-scale renewable energy into the transmission system. Researchers study transmission and grid integration issues and provide data, analysis, and models to enable the electric power system to more efficiently manage the variability of renewables such as solar and wind power.

Wind and solar energy offer environmental benefits, low operating costs, and reduced dependence on foreign fuel. However, wind and solar generation vary with wind speed and solar insolation. This variability affects how transmission systems with high penetrations of renewable energy sources operate. NREL researchers are identifying these effects and finding solutions to address them to enable transmission grid integration.


  • Power systems simulation – Expertise in large grid integration studies, such as production cost and dynamic modeling and simulation of large power systems
  • Transmission system planning – Expertise in the planning of transmission-level power systems
  • Transmission and distribution system co-simulation – Expertise in the co-simulation of combined transmission and distribution systems to gauge the impact of distributed energy resources on the bulk system and how bulk system operations impact distributed energy resources

Featured Studies

Eastern Renewable Generation Integration Study

The largest-ever simulation of the electric grid using the power of high-performance computing.

Western Wind and Solar Integration Study

Exploring whether we can integrate large amounts of wind and solar into the U.S. western electric grid.

Hawaii Solar and Wind Integration Studies

Studying the effects of high penetrations of renewables on Hawaiian island grids.

North American Renewable Integration Study

Analyzing pathways to modernize the North American power system.

Carbon-Free Resource Integration Study

Investigating the impacts of carbon-free generation on electric power systems.


An Extended IEEE 118-Bus Test System with High Renewable Penetration, IEEE Transactions on Power Systems (2018)

Solar, wind, hydro and load data

System as CSV files and FAQ

Plexos model as plexos file

Plexos model as Excel file

On the Path to SunShot: Emerging Issues and Challenges in Integrating High Levels of Solar into the Electrical Generation and Transmission System, NREL Technical Report (2016)

Advancing System Flexibility for High Penetration Renewable Integration, NREL Technical Report (2015)

Review and Status of Wind Integration and Transmission in the United States: Key Issues and Lessons Learned, NREL Technical Report (2015)


Bryan Palmintier

Group Manager, Electrical Engineering