In the pursuit for renewable energy sources, man has naturally turned to the ocean for answers. The ocean offers an attractive source for energy if we are only able to tap it. One of the main energy solutions currently in progress is the harnessing of tidal power. Tides offer great energy possibilities. The motion of the water can be used to power turbines and the predictability of their movements is an added benefit. Although they are not yet widely used, tidal energy is a promising alternative energy source for electricity. The harnessing of such power has been slow due to high costs; however, technological advancements continue to introduce improvements that should reduce costs.
Tidal Power Technology
Tidal power is harnessed from the Earth’s tidal forces, created from the gravitational pull of the moon. Because tides are based on orbital patterns, it is a renewable resource that can be tapped for millions of years. There are two primary technologies that are being used to generate power: tidal barrages and tidal stream generators.
Tidal barrages are essential large dams built across an estuary that generate electricity by converting potential energy into mechanical energy. As the water level rises at high tide, the dam fills up where the water is contained in a large basin. When the water recesses at low tide, the energy is converted into mechanical energy as the water channels out through turbines.
Tidal stream generators work much like a wind mill. These generators use the kinetic energy of the flowing water to power turbines. They take up less space than a tidal barrage because they are essentially large columns deposited in the sea floor. Some generators may even be built into the columns of existing bridges to eliminate aesthetic problems and use the estuary space more economically.
Because tidal power technology is a relatively new and untried energy source, there are numerous concerns about the potential environmental effects on marine life. There are two main concerns: one, the turbines may harm marine life due to dangerous rotating blades; and two, salt water corrosion of the generators may cause harmful chemicals to enter the environment and add to the cost of maintenance. Other areas of concern include the effect on water salinity in tidal basins and the potential harm to plant life due to disrupted tidal cycles. Unfortunately, many of these problems will not be understood fully until greater experimentation and research is conducted on tidal power. And these studies are slow in coming due to the high costs and red tape surrounding such a new technology.