OreCon is the latest, with plans for a sort of giant, self-contained buoy that floats atop the water, each unit generating a megawatt and a half of energy. The company has raised $24 million, which it plans to use in building a full-scale example.
One of the problems with putting mechanical equipment in the ocean is that the salt and other chemicals in sea water tend to destroy moving parts. OreCon uses a design called the Oscillating Water Column to keep most of the parts well above water level.
this brief animation to get a better idea of what happens in an OWC.)
OreCon's innovation is using what it calls "multi-resonant chambers". In its proprietary design, the company deploys multiple OWCs around a 40 meter platform that's tethered to the sea floor a few miles off shore.
The first unit should be deployed somewhere off the coast of England in Cornwall, near Plymouth, where OreCon was founded six years ago. Closer to home, rival designs by Finavera Renewables and Pelamis Wave Power are planned for deployment off the coast near San Francisco.
The funding OreCon raised was for £12 million (about $24 million US dollars). The round was led by Advent Venture Partners, and Venrock, Wellington Partners and Northzone Ventures also participated.