The Tennessee Valley Authority Says It’s Boosted Power Supply By Five Hundred Megawatts—Enough To Fuel Nearly Three Hundred Thousand Homes. The New Aeroderivative Gas Turbines At The Johnsonville Combustion Plant West Of Nashville Can Now Provide Over One Thousand Two Hundred Megawatts To The Grid. Tva Officials Say The Turbines Can Ramp Up From A Cold Start In Just Five Minutes, Making Them Ideal For Meeting Spikes In Demand. The Upgrade Comes As Tva Experiences Rising Electric Usage Due To Population Growth And New Technologies. Additional Aero Units Are Already Under Construction In Roane County.