Abstract: A hydroelectric generator for buoyantly generating electricity in a body of water, includes a support platform anchored in the body of water. A buoyancy chamber carried on the support platform is configured to selectively receive a source of air to buoyantly elevate the support platform through the body of water, and alternately sink the platform by discharging the air and flooding the chamber. A turbine array carried on the support platform is oriented to receive a relative water flow when the support platform ascends and descends through the body of water. An electric generator is operatively connected to the turbine. The system uses natural buoyancy to proactively drive an array of generating turbines through the water. The operator is in control of when electricity is generated and can choose to produce that electricity during times of peak demand when electricity prices are highest.