Tidal Energy: Advantages, Disadvantages, and Future Trends
Tidal energy is a growing renewable, clean, and environmentally friendly energy source that produces far fewer greenhouse gases than fossil fuels such as coal and oil. Moreover, its high predictability and elevated power output are also among the advantages of tidal energy. In this article, we examine what tidal energy is, its advantages and disadvantages as well as the future trends of this still unpopular but highly promising renewable energy source.
What Is Tidal Energy And How Does it Work?
Tidal energy is a form of power produced by the natural rise and fall of tides caused by the gravitational interaction between Earth, the sun, and the moon. The potential or kinetic energy of tide movement is captured and converted into electricity. This energy is renewable, derived from natural sources that are replenished at a higher rate than consumed, creating far less greenhouse gas emissions than burning fossil fuels. The global potential for tidal energy is huge, estimated to be around 500 gigawatts in 2020, equivalent to about one-fourth of the world’s coal capacity at that time.
3 Tidal Energy Technologies
Tidal energy technology can be classified into three types: tidal range, tidal current, and hybrid forms technologies.
1. Tidal Range Technologies
Tidal range technologies make use of the potential energy in the difference in height between high and low tides.
Tidal barrage makes use of tidal range technologies. Similar to dams or barriers, the barrage is constructed to hold a large body of water. The difference between the water height inside and outside the enclosed area will then cause water to flow from one side to the other, letting the water flow through the turbines inside the barrage, thus generating electricity. Annapolis Royal Generating Station in Canada is a power plant that used tidal barrage.
Tidal lagoons are very much like tidal barrages, except that they are not necessarily
connected to the shore and can sit within the ocean. The environmental impacts brought by the lagoons are far less than those of tidal barrages, making them an encouraged alternative to the latter. Other newly developed tidal range technologies include tidal reefs, tidal fences, and low-head tidal barrages.
2. Tidal Current Technologies
Tidal current technologies – or tidal stream technologies – make use of the kinetic energy of moving water to power turbines, similar to how wind turbines are moved by air. Due to its relatively low cost and limited ecological impact, this method has become more prevalent compared to tidal range technologies.
Horizontal- and vertical-axis turbines are an example of this type of technologies. The rotors of the turbine are turned by tidal currents, oriented either horizontally or vertically. Tidal kite, best used in slower tidal flows area, is also a common tidal current technology. The kite is tethered to the seabed, flying through the water with a turbine attached below its wing to generate power from motion. With up to 398 megawatts of generation capacity, the MeyGen Tidal Energy project in Scotland is expected to be the largest tidal generating station with tidal current technologies.
3. Hybrid Forms Technologies
Hybrid forms make use of both tidal current and tidal range technologies for electricity generation. Dynamic Tidal Power (DTP) is a recent development in these technologies. A long dam is constructed perpendicular to the coastline, with a barrier built at the end of the dam. DTP makes use of the height difference to create potential energy, while also using turbines to generate electricity.
To read the complete article on Tidal Energy, please click the below to Earth.org: