Tennessee Valley Authority. Watts Bar Dam hydroelectric plant. One of four tube-generating units which produce electric power at TVA's Watts Bar steam plant. This plant will supplement the big hydroelectric installations at Watts Bar Dam, which has an authorized output of 90,000 kilowatts, and a possible ultimate of 150,000 kilowatts. Each of the four big turbo-generators in the steam plant is rated at 60,000 kilowatts