First osmosis power plant

I recall hearing of this a couple of years ago. So it's interesting to read that the prototype is now producing power. It looks like quite an exciting development from a process that I am surprised produces the kind of power it can apparently do.
"In the prototype plant, the two solutions used are salt and fresh water, siphoned from near the point where they meet at the mouth of the fjord. The two liquids are pumped to either side of a membrane, where osmosis creates a pressure equivalent to a column of water 120 metres high. This is used to drive a turbine and generate electricity. Many of the world's major cities are on river estuaries that could be ideal for osmotic power generation. Unlike wind and solar power, it can provide a continuous source of energy, although seasonal river-level changes do cause some fluctuations."
First osmosis power plant goes on stream in Norway - environment - 26 November 2009 - New Scientist: