Introduction to Ocean Power Technologies
We previously learned about the Oscillating Water Column used to generate energy from ocean waves, and in this article we will learn about another ocean power technology of a similar nature.
If you have been to a port or a beach for swimming or sightseeing, you must have seen bright colorful objects floating in water at a distance. These objects are known as buoys. Buoys are generally used to caution ships or boats, regarding some underwater hazards or approaching port or an obstacle. A buoy doesn’t have any application other than signifying demarcations, but scientists have now come up with a way to put these buoys to a productive use, and that too a significant one.
A method to harness renewable energy of oceans by using bright colored buoys have been deployed at many ports. These buoys, known as powerbuoys, acts as an ocean energy converter. Anchored to the sea bed, they produce clean and low cost energy. Introduced by Ocean Power Technologies, these powerbuoys will utilize the wave energy to convert wave motion into electrical energy.
Let’s see how.
Construction and Working
The construction of a buoy is simple and robust. The body is made of simple steel and consists of a hydraulic system with a vertical piston arrangement. Most part of the buoy is submerged in water. The piston is attached to a generator by means of a mechanical arrangement. The rise and fall of the waves move the piston inside the buoy which then operates the generator.
All the buoys are connected to the shore power grid by means of cables. The low voltage electricity from all the buoys are collected to form a power of 100 plus megawatts. All the buoys are provided with an inbuit disactivation system which turns the buoy off incase of rough weather in order to prevent damage. As most of the part remains inside the water, the mechanism is not affected by any external factors.This is done by sensors that keep a watch on the near by water environment. It also measures the data and sends it to the shore. In case of a large incoming wave, the sensor mechanism automatically stops the buoy to operate till the condition become normal.
The main advange of this system is that it occupies a smaller area as compared to other fields for generating energy. A field of buoys producing 10 megawatts of electricity will occupy only 30 acres of water surface. The field is generally located at a distance of 1-3 miles from the shore with the buoys distributed in the range of 50 meters. The First Buoy farm of such type is located near the nothern coast of Spain. The technology is also used by the U.S navy to power some of their projects.