When renewable energy is being considered, the two forms that spring to many peoples’ minds are solar and wind power, but there is another form worth considering: tidal power. Tidal power converts the energy of the oceans’ tides into electricity. Though it hasn’t been widely used due to high cost and relatively low availability, recent advances in technology and design are allowing this form of power to be cheaper and easier to obtain.
Tidal power has definite benefits. It is, for one thing, almost endlessly renewable, making use of the gravitational relationship between the earth and the moon. Tides are also extremely predictable, even more so than sunshine and wind, which can be inhibited by weather patterns.
There are currently three methods of harnessing tidal power. Tidal stream generators, or TSGs, capture the kinetic energy of water as it moves through a turbine and convert it to mechanical energy, much in the way that wind turbines convert the energy of moving air. Alternately, the tidal barrage method uses barrages, or dams, to make use of the potential energy found in the water level differences between high and low tide. These dams are similar to other hydroelectric dam systems, but typically much larger. The last method, dynamic tidal power, or DTP, is still in its theoretical stage, but proposes to use both potential and kinetic energies as they interact in tidal flow. Unlike the tidal barrages, this energy would be harnessed in the open sea, rather than in tidal estuaries.
As of now, tidal power is being used in several parts of the world, including Northern Ireland, China, France and Canada. Other power plants are planned for South Korea, Scotland and India within the next ten years, and many proposals have been made for these kinds of plants in the US as well.
Below are some interesting online references we’ve found that will help you learn more about tidal power.
SeaGen: the project website for the world’s first tidal stream generator
Ocean Energy Council: answers some FAQs about tidal energy
Tidal Power US: a brief and illustrated overview of tidal power
Wall Street Journal: Tidal energy company brings turbine prototype to Maine
HydroWorld: Hyundai completes trial tidal power system in Korea
Daily Echo: Tidal energy proposed in Poole, England
Seattle Times: Data collected for Washington tidal project
BBC: Tidal power plan not happening in England, highlighting some of the controversy over the energy source
Recharge: Work begins on Scotland’s tidal energy device
And just to show you that maybe times haven’t changed, check out this 1936 article from the Reading Eagle, which reports on a debate in Senate over tidal power.