The Ocean's Magnificent Energy

The ocean's waters cover three-fourth of the Earth's surface and can present a rather tremendous source of energy. Some believe that the oceans will be able to produce a great amount of renewable energy around the world.

Two types of energy are produced by the ocean, thermal energy from the sun and mechanical energy, from the tides, waves and oceans current.

Being that the ocean cover 70% of the Earths surface, they are the world's largest solar collectors. The surface of the water is heated much more by the sun than the deeper waters. This temperature difference makes thermal energy.

Ocean Thermal Energy Conversion (OTEC), is a process that uses the oceans stored heat energy to produce electricity. This process works best when the difference between to water on the oceans surface, and the deeper water is right around 20 degrees Celsius (36 degrees Fahrenheit). Bringing the cold water to the surface, requires a large diameter intake pipe, submerged into the oceans depths around a mile or more.

There are three types of OTEC systems. There is the closed-cycle, the open-cycle and the hybrid. The closed-cycle system uses the ocean's warm surface water to vaporizes a low boiling point fluid, such as ammonia, to rotate a turbine to produce electricity. Open-cycle systems place warm sea water in a low pressure container, where it boils. The steam that is produced then passes through a turbine. The hybrid system combines both the open and the closed-cycle systems.

Rather different from thermal energy, is mechanical energy. The sun affects all of the oceans activities, however the tides are caused by the gravitational pull of the moon, and the wind is the primary cause of the waves. Energy from the tides and waves are not as consistent as the oceans thermal energy. Another mechanical energy, is the ocean current.

Due to the rotation of the earth, and the pull from the moon and the sun, tides are produced. The simplest system for a tidal plant is a dam, also known as a barrage, across an inlet. At high tide, sluice gates on the dam, allow the tidal basin to fill up, and empty through a turbine system on the outgoing tide.

Some systems are able to generate energy on both, incoming and outgoing tides. Currents there are two commercial size barrages in operation. The greatest disadvantage to a tidal plant, is the effect it can have on plants and animals.

When the wind blows over the surface of the ocean, ripples are created. As the wind continues to blow, the ripples become bigger. They become chops, waves, and finally swells. The oceans waves produce a drastic amount of energy. Two to three million megawatts is the estimated total energy in waves breaking around the world.

To be able to use wave energy, it to bend, or navigate the waves into a narrow channel, where they will increase their power and size. Now the waves can either be channeled into a catch basin, or to spin turbines directly. There are a few small wave energy plants, but no commercial ones at this time. Small, on shore sites could produce enough energy to power local communities, in the immediate future.

Wind energy does not rely on the ocean waters directly, although the temperature of the oceans water, has an effect on ocean winds, which in turn effect wind energy. Wind energy is produced using wind turbines, set up on wind farms that have to be placed where the wind constantly blows. The conditions along much of the U.S. coast, are great for this.

There are plans to build an offshore wind plant off the coast of Cape Cod, Ma. Many people feel that the use of turbines will ruin the view of the ocean, and are opposed to putting turbines just offshore. People see wind energy as a good thing, it does not pollute to environment, and is a renewable source of energy. Some even see it as an alternative to fossil fuels.

sources:
www.mms.gov
www.oceansatlas.org