The strong tidal currents flowing in and out of San Francisco Bay used to be one of the deterrents to prisoners trying to escape from the prison at Alcatraz by making it extremely difficult to get from the island to the mainland. Soon, those same currents may be put to use to provide electricity to communities in the Bay Area. Pacific Gas and Electric Company is teaming up with San Francisco and Golden Gate Energy to examine the viability of installing tidal power generators in the water to harness all that energy.

The feasibility study will start this summer and should be complete in about a year. They will measure how much energy might be available and look at the technologies that are available to capture some of that energy as well as do an environmental impact study. PG&E will kick in $1.5 million to fund the study by outside consultants and San Francisco will put in another $346,000. A study by the Electric Power Research Institute in 2006 indicated that the tides of San Francisco Bay could provide one of the biggest sources of tidal power in the world.

[Source: Pacific Gas and Electric]

Starting August 20th, Marine Current Turbines will install the worlds largest tidal current turbine in Northern Ireland's Strangford Lough. The 1.2MW turbine will be the first commercial scale underwater turbine powered by tidal currents. The system will generate enough electricity to power 1,000 homes.

The system will act as a prototype for even larger installations in the future. Based on the experience with this system, the company plans to scale up the technology to build a 10MW tidal power farm within the next three years and wants to have 500MW of tidal capacity by 2015. The company received a £4.27m grant to cover half the cost of the installation.

The turbine blades spin about 10 to 20 revolutions per minute which should be slow enough to prevent problems with nearby marine life.

[Source: Marine Current Turbines via TreeHugger]

One of the complaints about using hydrogen as a fuel, or more accurately as an energy storage medium, is that the energy required to produce hydrogen, exceeds the energy output. If hydrogen is being produced via electrolysis powered by fossil fuel electricity, this is a very serious issue. However, if you can find a pollution-free means of powering the electrolysis process, you can largely overcome this. An inventor in Houston, Texas has developed a mechanism that uses wave power to generate electricity. It consists of floats connected to a flywheel generator, that would be anchored underwater. As the waves go by, the float oscillates, driving the generator. The resulting electricity, could be used for electrolysis. The Swell Fuel website includes videos demonstrating a prototype unit. If this could be made to work in large off-shore installations, it could provide a huge amount of truly pollution-free, renewable energy.

[Source: Swellfuel.com via Hugg]