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Transmission constraints have been a recurring challenge for our electric power system. Transmission is required to meet growing electricity demand, to maintain electric reliability, and to access both variable and conventional generating resources.

Historically, the addition of new generation facilities on the electric power system has been accompanied by new transmission. For example, federal hydropower facilities developed in the 1930s, 1940s, and 1950s were supported by new transmission facilities owned by the federal government. Large nuclear and coal plants built in the 1960s and 1970s required interstate transmission infrastructure to deliver the electricity they produced. Likewise, the development of solar and wind generation in the United States will likely involve the development of new transmission.

Several studies have found that, although the cost of building transmission lines to access wind resources are significant, consumers benefit from the lower energy-production costs of solar and wind over conventional generation. The Joint Coordinated System Plan, a conceptual transmission and generation plan for the Eastern Interconnection of the United States, indicates that a 20% wind scenario by 2024 would result in a benefit-to-cost ratio of 1.7:1. In addition, transmission expenditures as a percentage of the overall cost of electricity to consumers are dwarfed by the cost of electricity production (i.e., fuel, operations, and maintenance) and the capital costs of generation development. The Joint Coordinated System Plan study found that incremental transmission costs are 2% of the projected wholesale energy costs for 2024.

NREL is addressing transmission constraint issues through its work on: