Recently, there are glowing attentions of utilization of renewable energy to ensure energy safety for human's sustainability.
In addition to the common renewable energy such as solar and wind, we are focusing on a relative new renewable energy Blue Energy which can be obtained when mixing two solutions with different salinity.
Here, we would like to introduce major two methods (PRO and RED) to convert this blue energy into electric energy.
In these methods, we only need two solutions with different salinity (e.x., seawater and river water) without any toxic, pollutive chemicals and CO2 emission.
Furthermore, blue energy can be used as stable energy resources compared with solar and wind energies.
Pressure-Retarded Osmosis (PRO)
PRO (also called as Osmotic Power Generation) utilizes a semi-permeable membrane located between two solutions with different salinity such as seawater and river water.
Because only water molecules can go through the membrane, spontinuous water transport from lower salinity side to higher salinity side is occurred due to the osmotic pressure difference.
Then, increasing amount of water stream at high salinity side drives a hydraulic turbine for electric power generation.
PRO Demo Movie
Reverse Electrodialysis (RED)
RED (also called as Dialytic Battery) utilizes two ion exchange membranes (cation and anion exchange membranes (CEM and AEM, respectively)) stacking alternately higher and lower salnity solutions in between.
Because only canion (ex. Na+) and anion (ex. Cl-) can go through the CEM and AEM, respectively, electrochemical potential between the two solutions generates a voltage.
Then, a redox reaction at electrodes set at the end of RED multiple cells allows to convert the ionic current into an electric current for electric power generation.
