The idea
Are Børgesen, a commercial Airline Pilot, is President and Founder of Tidal Sails AS. With his background in sailing, diving, and skiing, the idea developed after a regatta, sailing against the current.  After a half hour in the same position with the wind from behind and the spinnaker up, it came to him, the idea of turning the sailboat upside down. It would certainly take a lot to stop him then, with a modest 2-3 kts current catching the spinnaker below the surface!

The Business
Tidal Sails AS was formed in 2004.
The company is developing and commercializing a unique
renewable energy technology that harnesses ocean currents and
tidal streams and converts it into emission-free electricity using
underwater sails.

Sails have the potential to surpass any other tidal technologies under development as regards extraction efficiency, prospects for cost reduction, and acceptability. The energy converter is a series of underwater sails, affixed to wires strung across the tidal stream at an angle. The sails are driven back and forth by the tidal flow between two stations, at one of which the generator is installed.

The technology, and indeed the basic principle of this unique solution to extracting energy from tidal streams, is protected by patents worldwide.