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Major tidal power pros and cons

Published 17 March 2017

Though the development of the tidal power is at the nascent stage, it is estimated to have a vast potential globally. It is generated from converting energy from the force tides into power. Tidal energy production is more predictable compared to wind energy and solar power. Despite this, tidal power is still not exploited widely even as the world's first large-scale tidal power plant became operational in 1966. However, increase focus on generating power from renewable sources is expected to accelerate the development of new methods to exploit the tidal energy.

Here are the pros and cons of tidal power:

Renewable: As it is derived from tidal waves, which result from the gravitational pulls from the sun and the moon and the earth’s rotation around its axis, the energy is classified as a renewable source. Compared to limitations in power generation from finite fossil fuel reserves, tidal energy does not have any such constraints. Taking this into account, the tidal energy generation may last for thousands of years as long as its tides remain.












Image: MeyGen tidal stream project in Scotland’s Pentland Firth will rely on ABB technology. Photo courtesy of ABB.

Environmentally friendly: As the tidal power generation emits no harmful gases into the atmosphere, it is an environmentally friendly energy source. Further, the tidal power projects do not need much space compared to solar farms which require a large area of land for installation of modules. Tidal power installations also occupy less space compared other modes of power generation.

Predictability: As it is easy to know the occurrence of tidal currents, the scope of a tidal energy project can be measured accurately. The construction of the projects can also carried out with correct dimensions based on the formation of high and low tides in certain cycles. Assessment of these factors can help easily determine the size and capacity of a tidal plant at a particular area.  

Cost effective: Given the longer life span of tidal power plants compared to those that depend on fossil fuels, they are considered as cost-effective. Also, the tidal plants can be effective at low tides speeds and produce power to bring down the overall costs.  
















Image: Illustration of the Deep Green marine power plant. Photo: courtesy of SCHOTTELGroup.

Drawbacks of tidal power projects:

Site availability constraints: Limited availability of sites has remained a major constraint in the development of tidal power projects. The limitation has restricted the growth of tidal power projects worldwide. However, recent innovations in design and turbine technology for tidal power are expected to offer a potential to increase the installed capacity of tidal plants. The technological developments are also expected to result in reducing economic and environmental costs of the projects, thereby increasing their availability.

Sites close to land: Tidal power plants have to be constructed near to the land, as high tidal currents are needed to produce power. A huge variation in tides and tidal velocities can significantly increase the potential of a site for tidal electricity generation. Though the places where there is variation in tides, offer greater potential for tidal projects, scientists are trying to develop technology which can generate enough energy even in low tide environment.

Environmental effects: The impact of tidal power projects on the environment is yet to be ascertained precisely. Tidal power can damage marine life, as tidal turbines with their rotating blades may lead to deaths of living creatures in a sea. Noise from the rotation of the turbines may also impact fish habitations in the tidal power locations. Tidal energy can also impact the quality of water and sediment processes.

Tidal barrage: Installing a tidal barrage may result in a change to shoreline within a bay, damaging an ecosystem that relies on tidal flats. Flushing of the bay may also be affected by the prevention of the flow of water in and out of the bay. As a result, there may be reduction in saltwater, impacting marine life.