Energy From The Waves
Ocean waves are caused by the wind blowing across the sea. There is tremendous amount of energy stored in the ocean waves. Waves are a powerful source of energy.
The total power of waves breaking around the coastlines all over the world is estimated at 2-3 million megawatts. One way to harness wave energy is to focus the waves into a narrow channel which increases their power, size and impact. The waves can then be directed into a catch basin or may be used directly to spin turbines.
There are a few small wave energy plants, but no big commercial ones. The best potential can be harnessed on small, on-shore sites for immediate future. These produce enough energy to power local communities.
How it works
The world’s ocean may in due course provide us with energy to power our homes and businesses. At present, there are few ocean energy power plants and most of which are small. But how can we get energy from the ocean?
Wave energy is produced when electricity generating turbines are placed on the surface of the ocean. Energy generated is determined by corresponding wave height, wave speed, wavelength, and water density.
There are three basic ways to tap energy from the ocean waves. These methods are dependent on ocean behavior. We can use the ocean’s high and low tides, or we can use differences in water temperature in the for energy trapping.
The float or buoy systems use the rise and fall of ocean swells to drive hydraulic pumps which can be mounted to a floating raft or to a device fixed on the ocean floor. A series of anchored buoys rise and fall with the wave. The movement strikes an electrical generator and makes electricity. This is then shipped ashore by underwater power cables.
The other method being, oscillating water column devices, in which the motion of waves at the shore, enter a column and forces air to turn a turbine. The column fills with water as the wave rises and pumps out as it descends. In this process the air inside the column gets compressed and heats up, thus creating energy. That energy is thus harnessed and sent to shore by electrical cable.
This method relies on a shore-mounted structure to channel and concentrate the waves into an elevated reservoir. It is called tapered channel or tapchan system. Water flows out of this reservoir generates electricity, using standard hydropower technologies.
Challenges of Using Wave Energy
In general, wave energy generation has the following advantages and disadvantages.
- The energy is free – no fuel is needed
- No waste is generated during energy capturing or generation
- It is not expensive to operate and maintain
- It produces a significant amount of energy.
- It is highly dependent on the waves. Hence variable energy supply
- Needs a suitable location, where waves are consistently strong
- Some setups are noisy
- They must be able to withstand extreme rough weather
- High investment to develop visual impact, if above water or on shore
- It can disturb marine life Poses a possible threat to navigation from collisions due to the low profile of the wave energy devices above the water, making them undetectable either by direct sighting or by radar
- May interfere with anchorage lines with commercial and sport-fishing
- There is an overhead of maintaining electric transmission lines.
Despite active inventions which are making efforts to capture power from the waves for the last two centuries, there is still not a wide application of wave energy devices as power generators. The technology is definitely there but the sour reality being that over and above cost the consumer is unwilling to pay at this point of time. The system will work itself out. The price of fossil fuel generation will become unimaginably expensive to consume and wave generated power will fall in place and price.