Systems and methods of power generation with aquifer storage and recovery system

A method, comprising:

• with an aquifer storage and recovery system comprising a well bore, a pump in fluid communication with the well bore, an electric motor coupled to the pump, and a drive unit configured to control operation of the electric motor, flowing water into a subterranean aquifer formation through the well bore such that the pump rotates in a reverse direction and drives the electric motor coupled to the pump in the reverse direction to operate the electric motor as a generator;
• determining a power output of the electric motor;
• determining a difference between the power output of the electric motor and a first power output set point;
• and
• with the drive unit, controlling a rotational speed of the electric motor based at least in part on the difference between the power output of the electric motor and the first power output set point by varying a frequency of a drive signal output by the drive unit to the electric motor;
• detecting an increase in power output beyond the first power output set point after changing the frequency of the drive signal;
• and
• storing the increased power output as a new power output set point.

An aquifer storage and recovery system, comprising:

• a pump disposed in a well bore that communicates with a subterranean aquifer formation;
• an electric motor coupled to the pump;
• a drive unit configured to control operation of the electric motor;
• a down well flow control valve disposed in the well bore and in fluid communication with the pump;
• and
• a controller configured to:
• flow water into the well bore from a source reservoir through the pump and into the subterranean aquifer formation such that the pump rotates in a reverse direction and drives the electric motor coupled to the pump in the reverse direction to operate as a generator;
• operate the down well flow control valve to maintain pressure in the well bore at a pressure set point;
• determine a power output of the electric motor;
• determine a difference between the power output of the electric motor and a first power output set point;
• and
• operate the drive unit to control a rotational speed of the electric motor based at least in part on the difference between the power output of the electric motor and the first power output set point by varying a frequency of a drive signal output by the drive unit to the electric motor;
• wherein the controller is further configured to detect an increase in power output beyond the first power output set point after changing the frequency of the drive signal and store the increased power output as a new power output set point.

An aquifer storage and recovery system, comprising:

• a pump disposed in a well bore;
• an electric motor coupled to the pump;
• a drive unit configured to control operation of the electric motor;
• a down well flow control valve disposed in the well bore, the down well flow control valve being coupled to a sleeve and coupled to a one-way valve, the one-way valve being disposed within the sleeve, the pump being disposed below the down well flow control valve and in fluid communication with the sleeve, wherein the sleeve and the one-way valve are configured such that water flow into an aquifer flows through the sleeve to the pump and bypasses the one-way valve, and water flow out of the aquifer flows into the sleeve, through the one-way valve, and into the down well flow control valve;
• and
• a controller configured to:
• flow water into the well bore from a source reservoir through the pump such that the pump rotates in a reverse direction and drives the electric motor coupled to the pump in the reverse direction to operate as a generator;
• determine a power output of the electric motor;
• determine a difference between the power output of the electric motor and a power output set point;
• operate the drive unit to control a rotational speed of the electric motor based at least in part on the difference between the power output of the electric motor and the power output set point;
• and
• operate the down well flow control valve to maintain pressure in the well bore at a pressure set point.