Large dam upgrades in North America are squeezing every megawatt out of the grid as efficiently as possible by converting century-old powerhouses and replacing decades-old turbines. Construction is under way at several sites, from Pennsylvania to British Columbia. Earlier this month, PPL Montana began upgrading its Rainbow Dam, a 36-megawatt dam on the Missouri River, six miles northeast of Great Falls, Mont., where 200 workers are under the direction of Chicago’s Walsh Construction.
PPL Montana says the $230-million, 30-month project is the state’s single-largest energy investment in roughly 30 years. David Hoffman, PPL’s external affairs director, says the upgrade will increase dam capacity by more than 70% without changing the river flow.