Some of the most amazing natural occurrences in the ocean are waves and tides. Although both originate in water, they are very different in how they produce energy when it comes to reliability, power, and generation. As the world reduces its dependence on non-renewable energy sources, experts explore innovative, eco-friendly, and sustainable ways to generate energy. Like most bleeding-edge technology, it is costly to design and build. This article aims to answer the question, "What is the difference between wave energy and tidal energy?"
Tides are the rise and fall of water levels in the ocean due to the moon and the sun's gravitational pull on the earth. The sun's gravitational pull is not easily visible on water like the moon's pull. This is because the moon is closer to the earth than the sun.
There are various factors impacting the tides, including the shape of the coastline, variances in water depth, and the alignment of the moon and the sun.
The moon's rotation around the earth exerts a gravitational pull, forming a tide that moves across an ocean. The circling of the moon around the earth coincides with the rotation of the earth, which causes inertia that creates a tide on the opposite side of the planet.
All tides are not created equal. All coastal areas have high and low tides, but tidal energy can only be harnessed for electricity production if the difference between high and low tides is significant enough. The main tidal energy types include kinetic energy and potential energy. Kinetic energy is captured from currents of changing tides. Potential energy is captured from a change in the height of high and low tides. Tidal energy is beneficial since it is reliable as the moon's gravitational pull can be predicted. However, it doesn't have prolonged availability since it only generates power for 6-12 hours at a time, making it less reliable.
Harnessing tidal energy disrupts regular boating pathways and natural migrating routes for sea animals. Moreover, turbines can kill numerous fish in the area of power harvesting. But because its use can reduce reliance on the use of coal, it helps reduce carbon dioxide emissions.
Technologies used for generating tidal energy include barrages or tidal dams, which have a sluice across the water body. Hydro turbines are situated beyond the sluice. The varying water levels caused by tidal changes push through the sluice to move the turbine. But these technologies were not eco-friendly, resulting in the creation of tidal lagoons, underwater tidal turbines, and tidal fences.
Wave energy is energy generated by oceanic waves. When the wind blows across the ocean surface, waves are created. They're also called wind waves and occur on oceans, lakes, canals, and rivers. Waves are usually different depending on the height and distance between troughs and crests.
Duration, distance, and changes in wind speed affect the shape of waves. Also, the weather system impacts the size and shape of waves, which helps narrow down the waves' origin. For instance, high, steep waves that go up and down fast are newly created and result from nearby weather systems such as local storms. On the other hand, steady waves result from extreme weather conditions taking place further away, such as a storm happening in another hemisphere.
Wave energy, when harnessed, is useful for electricity generation, pumping of water into reservoirs, and desalination. The ability to produce energy is affected by the strength of the waves. Oceanic waves have a rough, vertical motion that carries massive amounts of kinetic energy, which is harnessed by wave energy technologies. Onshore and offshore systems are used to capture wave energy. Offshore systems take place in deep water and use hoses or pumps to harness energy by rotating turbines. Onshore systems operate along shorelines and capture energy from breaking waves.
Wave energy is sustainable since waves always wash ashore based on weather conditions, and they never stop forming. Wave energy technologies are not easily visible, which means they have a low impact on the aesthetic value of land, making them acceptable. However, it's hard to convert wave energy into electricity efficiently. It's also difficult to design and develop equipment, but they're robust and can withstand corrosion from saltwater and storm damage.
Wave energy technologies are of three types. The first utilizes buoys or floats to create electricity from oceanic swells that operate hydraulic pumps. The second one utilizes a swinging water column to create electricity from the rise and fall of water in a cylindrical shaft. This works at the shore. The water removes air from the shaft, operating an air-driven turbine. The third type uses a tapered channel located offshore or onshore. The technology focuses waves and steers them into a raised reservoir where turbines generate power.
Tides are the rise and fall of ocean levels resulting from the gravitational pull of the sun and the moon on the earth, while waves are caused by wind energy moving on the surface of the sea, which makes waves easier to measure than tides.
Waves are more noticeable than tides since tides are only noticed on the shoreline, depending on the amount of visible sand and water. Waves can easily be seen on the ocean's surface as they rise and fall.
Tidal energy fluctuates, which makes wave power a more sustainable energy source. While both wave and tidal energy have high startup costs, harnessing wave energy is environmentally friendly as harvesting tidal energy affects the migration routes of sea animals.