Most tidal energy systems use water captured at high tide which then are used to run turbines as the water is released at low tide. This works well enough, but a new system being tested by scientists at the University of California in Berkeley promises to generate lots of power from a much smaller and simpler installation.
The Wave Carpet is a flexible platform that sits about a foot above the seabed, supported by a row of hydraulic cylinders. As the ocean waves pass over the carpet, the changes in pressure created by the wave action cause the carpet to rise and fall, and this in turn pumps sea water through the hydraulic cylinders. The pressurized water is then brought onshore, where it passes through turbines to generate electricity.
The remarkable thing about this system is just how much power the UC Berkeley team says it can generate. Just 11 square feet of wave carpet can generate enough power for two houses, and 100 square feet of the stuff generates more power than an entire soccer field covered with solar panels. Another benefit is that waves operate 24/7, unlike solar power which obviously can't work at night, and wind power which requires wind.
The UC Berkeley team expects to start ocean testing of the wave carpet in 2016, and hopes to see it in commercial use by 2024.