Underwater energy sources can be a terrific way to supply the world with needed energy without producing any harmful emissions, pollution, and greenhouse gases that would contribute to global warming. Some types of underwater energy sources include tides, waves, currents and others. Technology advances more every day, and scientists are looking at the ocean for renewable alternative sources of energy to replace fossil fuels. The ocean currents, the tides, and waves in the ocean produce a large amount of energy, but harnessing that energy has proven to be tricky.

Underwater turbines are one solution to capturing underwater energy from currents. These machines resemble wind turbines, only they are much stronger since they have to stand up to the force of the roughest currents where they are placed. There are many areas that possess conditions that are ideal for these turbines, including off the coast of Maine in the northeast United States. The strength of ocean currents is extremely strong, strong enough to turn the underwater turbines and create electricity and other forms of energy.

Ocean thermal energy is another energy source available from the ocean. The surface of the ocean is warmed by the sun and a large temperature difference is seen between surface water and deeper water. This difference in temperature provides for thermal energy. This alternative energy source is renewable and dependable because the oceans and seas cover 70 percent of the entire world. Since this is the case, using the thermal energy provided by these waters can be a big leap forward towards eliminating harmful fossil fuels.

Mechanical energy is also available from the ocean. These energy sources include waves and tides. Tides are the result of the moon's gravitational pull and are found beneath the water's surface. Turbines can be used to capture this energy as well. These turbines must be placed carefully, concentrating on where tides are the strongest so that they can be most effective. Waves are also a source of energy, created by wind.

The problem with current, tidal, and wave energies is that they are not totally predictable and therefore dependable. The demand for power is constant and these energy sources cannot supply continuous power as it is needed. That does not mean that these energy sources cannot be combined with other alternative renewable energy sources though, like biomass energy, wind energy, and solar energy. Eliminating dependence on fossil fuels may mean using a combination of different methods, one of which may be underwater energy sources.

The oceans of the world hold a large amount of energy and surely technology will advance to the point where this energy can be used to substitute other more harmful energy sources like oil, coal, and natural gas. Harnessing the energy from the ocean in an efficient and cost effective method would be a tremendous breakthrough in alternative energy research. Right now, it takes a large amount of capital to start a project of this scope, and it may take years to acquire the right engineers and materials to build the necessary equipment that must be strong enough to stand up to rough waters and weather conditions. Because of the high costs involved, producing energy from machines like underwater turbines is not yet common. The concept is sound though and will only take time to be put into serious motion.