Transmission Infrastructure
NREL analyses support transmission infrastructure planning and expansion to enable large-scale deployment of renewable energy in the future.
Large-scale deployment of renewable electricity generation will require additional transmission to connect renewable resources, which are widespread across the U.S. but regionally constrained, to load centers. Long-term transmission planning, based on potential growth in electric loads and generation resource expansion options, is critical to maintaining the flexibility required for a reliable and robust transmission system.
NREL's transmission infrastructure expansion and planning analyses show that:
- Analysis of location-specific renewable resource potential and power delivery profiles are critical elements of assessing future transmission infrastructure upgrade and expansion requirements.
- Future utility resource plans and regional planning efforts need to engage a diverse range stakeholders—U.S. Department of Energy, FERC, NERC, and the regional entities, transmission providers, generating companies, utilities, regulatory agencies, energy offices, environmental interests, and investors.
Featured Studies
Interconnections Seam Study
Through the Interconnections Seam Study, NREL is identifying cost-effective options for upgrading the U.S. electric grid.
Geothermal Power and Interconnection: The Economics of Getting to Market

Geothermal Power and Interconnection: The Economics of Getting to Market summarizes the transmission and interconnection issues affecting geothermal technologies as these technologies mature and are commercially deployed. Key findings include:
- For geothermal power, the market of least resistance with respect to interconnection is in serving local base load (within the same balancing authority).
- Accessing regional markets via new transmission will depend on the ability to aggregate several geothermal plants in the same area or on aggregating geothermal with other complementary generating technologies, in renewable energy zones.
- Interconnection issues facing geothermal power differ greatly from those affecting wind power or other renewable technologies.
Data and Tools
NREL technology-specific GIS data and tools showing renewable energy resource potential, political, and infrastructure/utility data are used to support transmission and planning analysis.
Publications
- Renewable Electricity Futures Study. Volume 4: Bulk Electric Power Systems: Operations and Transmission Planning, NREL Technical Report (2012)
- Transmission Planning Process and Opportunities for Utility-Scale Solar Engagement within the Western Electricity Coordinating Council (WECC), NREL Technical Report (2011)