Tidal Energy: Will it Ever Compare to Solar?

From the water wheels that powered riverside mills for centuries, to modern hydroelectric power plants that provide electricity to millions, river currents have long been used to generate energy. Although tide mills have been used in the past, harnessing the power of the sea’s tidal flows to produce electricity is a more recent innovation. Ideas for tidal energy to generate electricity gained traction during the last century, but few got further than the drawing board.

One exception is the world’s first tidal power plant, completed in 1966. Located in La Rance, France, the plant has a 240-megawatt capacity. Today, there are a half dozen tidal power plants operating around the world, and another half dozen under construction, none of them in the United States. Finally, the U.S. stands poised to join the tidal energy community, with an application by private company Verdant Power to install a tidal power plant in New York’s East River under consideration by federal regulators.

Tidal energy technology usually employs underwater turbines that make use of the kinetic energy of tidal currents to generate power. Concerns over whether this technology would harm marine life have proven unfounded. Since water is much denser than air, turbines can turn slowly, yet still produce as much energy as wind turbines. A two-year environmental study conducted during Verdant Power’s preliminary installations showed no impact on fish life or migrations. The fish simply avoid the blades.

Tidal barrage systems are proving to be far more harmful to the environment than turbines. Essentially, tidal barrages are dams built across a tidal estuary. France’s tidal power plant uses the barrage system, and the La Rance plant has been the most studied for environmental impact. Research has found that barrages pose the same kind of threats to the environment as large dams, with some species disappearing, while others moved in, causing a major shift in diversity.

While Russia and South Korea currently have working tidal power plants, with more plants under construction, the rest of the world is struggling to catch up. China and Canada each have one tidal power plant. Britain, the Philippines and India have plants under construction. The United States is late in joining the party.

In comparison with solar energy, tidal energy is still in its infancy. The technology has great potential, but it will take time for governments to accept it as a viable option, let alone build the power plants. Solar power plants encounter the same time constraints, but unlike tidal energy, solar energy can be generated in small installations over a much broader area. American homeowners needn’t wait for tidal power to promote green technology. Residential solar energy systems are available nationwide.

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Tidal Energy: Will it Ever Compare to Solar?