To deliver power, BPA began building transmission lines in the 1930s. Today the system includes more than 15,000 circuit-miles of line. BPA’s high-voltage electric grid links virtually all utilities in the Northwest. BPA also operates large interregional transmission lines that connect the Northwest grid to Canada, eastern Montana, California and other areas.

These lines enable BPA and other utilities to bring power into the region when it’s needed, such as on very cold winter days, and to sell power outside the region when it is surplus to Northwest needs.