Dutch language video
“Blue energy” is tapped from places where river water reaches the sea. The key to this form of energy generation is difference in concentration of dissolved salts.
One very suitable location is the Aflsuitdijk in the Netherlands, where a dike of 32 km separates fresh from salt water. The ultimate potential here is 3 GW, based on a flow of 3300 m³/sec. Currently, a demonstration project is in place that provides more than 160 households with blue electricity (“blue” refers to water).
The key challenge is to develop suitable membranes.
Once the engineers get this to work, the method can be applied everywhere where rivers flow into the sea. And that’s a lot of places, thousands.
Related to blue energy is the possibility of storing energy in salinated water. Rule of thumb: 1 m3 salt water has an energy content of 1 kWh, as compared to fresh water. This is about the same as a conventional car battery, except with salt water, one can work with volumes the size of a lake. The company AquaBattery in Leiden is working on this topic.
[wikipedia.org] – Osmotic power
[deepresource] – Blue Energy (2012)
[deepresource] – Blue Energy Pilot Plant Operational in the Netherlands (2014)
[deafsluitdijk.nl] – De 9 meest gestelde vragen over Blue Energy