Exploring Alternative Energy – How To Use The Ocean To Generate Electricity

With water encompassing over 70 percent of the Earth, it would make sense to try and gain alternative energy from the ocean. Ocean Thermal Energy Conversion or OTEC is a way to do just that. French engineer Jacques D’Arsonval is the brainchild of the idea. In 1881, he felt that the thermal energy of the ocean would be able to provide a great, clean source of energy. In other words, the different temperatures of the ocean in deep and shallow waters will be able to run a heat engine, which runs efficiently with great temperature changes.

There are three states that are heavily involved in exploring OTEC. The United States is one of them and has a large OTEC facility in Hawaii. Tests are done here to learn more about the technology. It has been said to be the perfect place for OTEC because of the warm surface temperature and access to deep cold temperatures of the ocean. Japan, while not a great area for OTEC, created a closed-cycle OTEC plant on the island of Nauru. It uses the energy to power the plant and neighboring communities. India also sponsors OTEC operations and is looking for ways to get new and better energy.

There are three ways to use OTEC: open cycle, closed cycle and hybrid cycle. Of the three cycles there are also three locations, land-based, shelf-based and floating-based.

A closed-cycle system uses a fluid with a low boiling point to rotate a turbine. Warm surface ocean water is pumped in causing the fluid to evaporate and the vapor turns the generator. Cold ocean water is pumped through the other side, causing the substance to form back into liquid and start the cycle all over again.

An open-cycle uses the ocean’s warm surface temperature to make energy. Warm seawater boils when placed in a low-pressure container. The steam turns the low-pressure turbine, which in turns moves the generator. It is condensed back into liquid form when it comes in contact with cold temperatures from the cold seawater.

A hybrid-cycle contains features of both systems. In the hybrid system, warm water is flash vaporized causing the steam to vaporize the low-boiling point fluid. The vapors drive the turbine and the steam condenses with the cold temperature creating desalinated water.

While it sounds like a great plan and a wonderful way to use the environment in a safe manner, the problem is this technology is extremely expensive. The United States hasn’t run any new tests in almost 10 years because of the costs, especially with companies focusing on other energy sources. Few other countries have been working at ways to find an operational system. The reason why it is so expensive is because the main thing needed is a large pipe, sometimes a mile long to reach to the bottom of the ocean to get the cold water. Creating this pipe and maintaining the process costs too great of a price.

However one of the huge advantages to OTEC is that it provides more than just electricity. By bringing up the cold water from the bottom of the ocean, there are many other uses such as air conditioning, chill-soiled agriculture, desalination and mineral extractions. But there are concerns worldwide about the effects of using alternative energy from the ocean can cause on the environment. Unfortunately, because of the lack of research this question may never get answered.

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