An Understanding of Our Planet : How Does Wave Power Work

In order to comprehend the answer to the question 'how does wave power work', we must form an understanding of the powerful processes that create the waves we enjoy at the beach.

Forces around our planet are constantly working to form waves. These sources of energy are renewed and continually created on any large body of water in the world. Regardless of location or size, waves can happen anywhere. If the conditions are correct, even a moderately sized, land-locked, man-made lake can have waves break along its shore that resemble an ocean.

Many surfers enjoy the fruits of these conditions without ever asking themselves how wave energy works. Most surfers understand the concept of waves enough to know that certain areas have bigger waves than others, and these places usually have the best surfing conditions.

Some places around the world, such as around Hawaii and off the western coast of America, are known for their high waves. Surfers flock there, hoping to catch that one wave that they can tell stories about riding later. Other parts of the planet have only smaller waves. In these places, wave height will rarely break the two foot mark. All of these waves are created by the same conditions. The surf-style waves are caused by having better conditions than the ones that are smaller, but they all begin in the same way.

One fact that any surfer or beach-goer knows is that different wave sizes carry with them different amounts of energy. Waves that are particularly high will pack a greater punch. Those that come in quick succession will drag you along the sand with equal tenacity though. While all waves may look the same, the energy they produce can differ greatly.

Wave power is a renewable energy(just like solar and wind) that comes from the changing speed and heights of the swells in the ocean and can be harnessed using specific methods and devices.

Wave power is the direct result of wind interacting with water. So, technically, wave energy is caused by the wind. However, it’s not the same as tidal energy, which is the result of ongoing movement of ocean currents due to Earth’s rotation and gravity.

How Is Wave Power Generated?

The first question in the quest to understand how wave power works is 'how is wave power generated?' Wave power is created by the wind. Without wind, there would be no waves. This is why, on a still day, the surface of medium sized lakes can seem as still as glass. Without wind to stir the surface, there is nothing to make the water move around.

As our planet turns, creating night and day, the sunlight strikes the planet unevenly. This creates some spots where the air is hotter than others. As air becomes hotter, it rises. Cooler air rushes in to fill the gap by the hot air rising. This creates wind.

Once wind starts moving, it will continue to do so until it strikes a barrier that causes it to stop. On land, the wind is interrupted by everything in its way, including trees, mountains, and buildings. Even your car is a large enough obstacle to slow down the wind. On the open ocean, none of these barriers exist. The wind blows freely along the surface of the water.

This wind carries with it energy. You can feel this energy when the wind hits your body. It can be seen in objects being knocked around. Severe instances of this energy can form tornadoes and hurricanes. When this energetic wind blows along the surface of a body of water, it catches the water and begins to move it. The water forms ridges in its surface, which block some of the wind, transferring the energy of the breeze into the water.

Once this energy enters the water, it will move around. This is the point where the energy of the wind becomes the energy of the waves. This energy will get below the water's surface, forming a column of energy that moves along the water. This is how the waves get their energy. From here, they travel in whatever direction the prevailing wind that created them was moving. With enough energy in a body of water, the energy columns won't dissipate.

As this column of water energy approaches a shoreline, the ground beneath the energy column begins to slope upward. The energy at the bottom of the wave column finds itself being pushed upward. This is the point where the energy column begins to become a wave that we see on the water's surface. More energy pushes upward with shallower ground. Eventually, the height and steepness of the wave can no longer disobey gravity, and the wave curls over on itself. This creates the part of the wave that surfers enjoy riding.

Wave energy is an oscillating, irregular low-frequency energy source that is converted to 60-Hertz frequency and added to the electric utility grid. Right now, there are several wave electricity generation methods and ocean and sea wave energy devices that are being used. Some of them are the following:

1. Oscillating body. This is a wave electricity generator device which is placed either on the surface or submerged in the water, is moved back and forth or up and down by the waves to drive a generator.

2. Oscillating water column. This is basically the same when harnessing wind power. As the device moves, the air enters a chamber where it is compressed and decompressed by the movement of the waves. The air is decompressed as the high-powered turbine catches the air.

3. Another method is using a shore-based large structure that channels waves into a huge basin. When the ocean’s water level is lower than the basin, the basin is drained to run a turbine.

Wave Electricity Generation

These waves contain a lot of energy within them. It has been theorized that wave electricity generation could be twice the electrical generation capabilities of the entire planet. We only have to find a way to harness this power in order to turn it into electricity, and all of the world's power supply problems would be solved.

One problem facing makers of the wave electricity generator is that not every location on the planet produces ideal waves for harvesting. The type of waves needed for the different kinds of generators are, in some cases, quite specific. If the waves are too powerful, they could destroy the wave electricity generator. If the waves aren't strong enough, they may not trigger the generating mechanisms.

"Ocean and sea wave energy devices are being designed and tested around the world". Creating energy of any kind requires causing a turbine to turn. While this concept is basic, finding a way to get waves to turn the turbine with consistency has proven challenging. Different areas of the world require different types of ocean and sea wave energy devices.

Once scientists figure out how to capture the energy of the waves efficiently, our energy problems will be over. Until then, we will continue trying to find ways to harness the energy of the ocean without destroying the waves that surfers love so well.

Wave power: Is it effective?

Very few people have used or even heard about wave power. That means, very few understand how it works and how effective it is. To give you an idea, wind is the biggest renewable energy source. When combined with every ocean energy resources, which include wave power, this can provide up to two terawatts of electricity.

Wind power typically produces 300 watts per square meter on a sunny day; that’s about 100% of solar energy that can be harnessed during the same time period. These figures are way lower compare to what wave energy can offer which is about 30,000 watts per square meter. Yes, it’s very powerful and this is the reason why more and more nations are seriously considering using this renewable energy.

Benefits of wave power

1. It’s environment-friendly. Methods and devices that are being used to harness wave power don’t have propellers. Because of this, experts believe that harnessing wave power create less damage to the environment compare to other renewable energy technologies.

2. Wave power supply is abundant. Unlike solar and wind energy, wave energy can be harnessed at anytime as it occurs around the clock. Also, waves are more predictable as they’re propagating the oceans from long distance. Experts using renewable energy technologies can predict a wave energy reaching a wave farm at least 48 hours in advance.

3. From a business perspective, offering wave energy is extremely profitable as ocean energy is always available and is abundant. Once a company built a wave farm, maintenance and operation cost will go down significantly as they’ll get free water and fuel.

Disadvantages of Wave Power

Just like when harnessing other renewable energy resources, wave power can be extremely expensive. In fact, it is 400 times more expensive compare to coal that is priced around 5-10 cents per kilowatt. Money is also a problem for power companies, as they need to fund their research and development. Another challenge they’re facing is creating technologies that can withstand the harsh ocean environment.

Another challenge is the fact that ocean is a common place. Unlike when building power plants, companies can’t just buy a piece of the ocean the same way they buy a land for their power plants.

Lastly, as the process of harnessing wave power is relatively new (although the idea has been tossed around for hundreds of years), there might be some environmental issues that can surface along the way. Environmentalists are concerns as ecological systems might be affected.

What the public can expect

As experts have seen tremendous potential, public can expect that companies will continue to work very hard to master the process of manufacturing and later on, offering this renewable energy to the masses. However, don’t expect it in the near future. Experts agree that it might take 5-10 years tops before this can be realized.

However, it’s good to know that right now, capital cost per net kw are slowly going down. In fact, it’s cheaper compare to harnessing solar energy. In many areas where communities rely solely on diesel, investment returns from switching to wave energy can be extremely attractive.