This dataset shows the expansions to bulk electric transmission corridors in the contiguous United States that will be required by 2050 to balance renewable energy capacity (solar PV, wind, and offshore wind) across metropolitan statistical areas (MSAs) under a reference scenario projecting no changes in energy policy and under more permissive land-use assumptions. Balancing ensures that each of the 73 MSAs included in the analysis has access to a minimum level of renewable electricity supply on an annualized basis. For an overview of the "REF" frozen-policy scenario and "base" land-use assumptions on which this dataset is based, please refer to the "supplemental information" portion of this record.