Thursday, October 17, 2013

Wave Energy

Wave energy is a renewable source of energy. This energy is caused largely by wind blowing on the ocean surface. Wave power plants are plants designed to use wave power to generate electricity. To use wave energy we must choose the location where the waves are sufficiently frequent and shave enough strength.

  The energy of the wave decreases rapidly with depth of the wave, and thus at the depth of 50 m is only 2% of the energy just below the surface. Wave power is estimated to be 2 × 109 kW, which corresponds to a power of 10 kW at 1m of wavy lines. This power varies depending on the geographic location, from 3 kW / m in the Mediterranean up to 90 kW / m in the North Atlantic. Wave energy is a renewable energy source. It varies over time (more and bigger waves are there in the winter) and has a random character.

  Wave height is the highest during the winter, which coincides with the time of the high electricity consumption. The kinetic energy of the waves can start effectively transforming into electrical energy when the wave height is greater than 1 meter. Due to the natural resources of the waves, a high level of technological development, the large energy requirements and environmental conscience, the furthest in development of commercial power of waves came highly industrialized countries like the United Kingdom, Japan, Scandinavia and Australia.

  Today there are basically three known ways of using wave energy if categorized according to the method by which they accept waves. These are over buoys, floating piston and pendulum or spatula.

  Advantages of building power plants on the open seas are:

- better utilization of wave potential higher-potential area for field power, and those with higher total power for a given geographic location
- ability to supply offshore facilities
-ability to supply various types of sensors as autonomous energy system

  Objective shortcomings of floating objects are their reliability due to corrosion and mechanical unpredictable environment.

  Pacing device. The device works on principle that the kinetic energy of the wave motion transforms into a work of stop plate and the hydraulic pump which drives a generator.

  Buoys. The power of these devices can range up to 50 kW, but the advantage is the possibility to take a large number of the particular area, which is offset by small individual forces. Such devices are especially interesting for active ocean sensors as beacons, bait fish, sonar, communications repeaters etc.

  Advantages of building power plants near the coast compared to floating systems are the following:

    - lighter construction because they use classical construction equipment
     -easier maintenance of the plant because they are not required divers and boats
     -easier and faster control and replacement of defective parts
     -can serve as a breakwater

Wednesday, October 16, 2013

Renewable Energy Sources

 Renewable energy sources can be divided into two main groups: those are traditional renewable energy sources such as biomass and large hydro power plants, and "new renewable energy sources" such as solar energy, wind energy, geothermal energy, etc.
  According to collected data renewable energy sources provide about 18% of world energy, but much of the energy is produced in the traditional way, use of biomass for cooking and heating from 13 from 18%.
  From large hydro plants we receive around three percent. So when we exclude traditional renewable energy sources we can assume that the "new energy sources" produced only 2.4% of total global consumption.
  From these 3% goes to water heating, 0.8% in electricity production and 0.3% of bio fuels.
  It is believed that this share should be increased because the amount of non-renewable energy resources is rapidly dwindling, and their negative impact has significantly increased in recent decades.

  Sun delivers 15,000 times more energy than mankind can now spend, but nevertheless still a large number of people freezes and have not enough energy for their homes. Here we see that it is time to start to better exploit renewable energy sources.
  When we consider renewable energy sources their development is important for many reasons, and one of them relates to a major role in reducing carbon emissions.

    Geothermal Energy

  Geothermal energy is a form of energy that involves the use of heat inside the Earth. This type of energy can be used directly and indirectly. The use of geothermal energy can be varied for the application for the spa, to heat homes and greenhouses.

    Tidal Energy

  Tidal energy comes from the gravitational force of the Sun and the Moon. It is known that this type of energy can come from the area where is the big difference between high and low tide. The principle of operation is similar to that of a hydroelectric power plant. The main problem is stated in fickle tides and a small number of places that could be suitable for the use of this form of energy.

    Wave Energy

  Wave energy occurs in the form of transformed sun energy that creates constant winds in some areas. These winds then lead to permanent waves in some areas. Energy use in this way is not ideal. The main problem lies in the fact that this type of power should be built on the open sea, as the waves near the shore are weak. Price of this type of buildings is high, not to mention the problem of transferring the energy.