Membrane-based energy harvesting through salinity gradient of available upstream water resources

A system for harvesting energy through pressure retarded osmosis, comprising:

• a first upstream water source drawn through a low salinity feed line with a first pump upstream of a semi-permeable membrane housing configured to produce a pressurized low salinity feed stream;
• a second upstream water source drawn through a high salinity feed line with a second pump upstream of the semi-permeable membrane housing configured to produce a pressurized high salinity feed stream with a pressure in a range of 1,000,000 to 50,000,000 Pa;
• the semi-permeable membrane housing, wherein the semi-permeable membrane housing comprises:
• a container;
• the semi-permeable membrane dividing the container;
• a low salinity side of the semi-permeable membrane housing in fluid communication with the pressurized low salinity feed streamline at a first end of the semi-permeable membrane housing;
• and
• a high salinity side of the semi-permeable membrane housing in fluid communication with the pressurized high salinity feed streamline at the second end of the semi-permeable membrane housing;
• a low salinity exit line at a second end of the semi-permeable membrane housing opposite of the first end;
• a pressurized mid-salinity exit line at the first end of the semi-permeable membrane housing upstream of a turbine;
• the turbine in fluid communication with the pressurized mid-salinity exit line;
• a generator coupled to the turbine;
• and
• a depressurized mid-salinity exit line downstream of the turbine.