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8.3.4: Tidal Power – Conclusions

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    The tidal motions of ocean and sea waters offer an renewable energy source with vast potential. This energy is absolutely clean, has a minimal envi- ronmental impact, and, despite its intermittent nature, is highly predictable (centuries ago, sailors already knew the art of forecasting tidal height and tidal current strength). According to US governmental sources, tidal streams in the United States may provide power equal to nearly 10% of the country’s total electric power consumption (3911 TWh in 2017). Another official in- stitution, the presents more optimistic estimates – that even more than one third of all needs for electricity used in the U.S. could be satisfied by power drawn from the seas.

    It is estimated that harnessing local tidal currents can provide about 20% of Great Britain’s needs for electricity. These expectations are consistent with the estimates of the total global resources of tidal power given in the article of Encyclopedia Britannica, quoted at the beginning of this Section (3000 GW, which is nearly 20% of the current global consumption of electric power).

    But so far, ocean resources (including wave power) are expected to pro- duce only 1 GW of electric power worldwide by 2020. Half of that power will come from the two large existing tidal barrage facilities in France and in South Korea. The remainder may come from a large number of small installations, none of which being a real commercial facility – they are all small-scale prototypes, or demonstration installations. 1 GW is only a tiny fraction of the power generated worldwide by two other major renewable sources: wind (over 500 GW in 2017) and solar (over 300 GW in 2016).

    Why is the marine energy lagging so badly behind? There are several conceivable reasons. In Author’s opinion, the present low price of mined fuels plays its role. But it should affect wind power and solar power as well, but it doesn’t. But wind and power certainly gets support from people regardless of where they live, while for inland-dwellers the term “marine technologies” may sound like an abstraction. Well, but it would hardly explain the proportion of one to one thousand.

    Some more insight into the problem is given in a recent article Will Tidal and Wave Energy Ever Live Up to Their Potential? by Sophia Schweitzer1. She lists several other possible reasons, such as environmental concerns and the challenges of underwater technology. But, more optimistically, she also points out that to signs indicating that a strong growth of interest in marine power generating may happen in near future. Well, let’s then be optimistic and hope that it will really happen!


    1. Sophia V. Schweitzer is an independent science writer focusing on climate change and the environment. Her work has appeared in numerous publications including Pacific Standard,, and American Forests.

    8.3.4: Tidal Power – Conclusions is shared under a CC BY 1.3 license and was authored, remixed, and/or curated by Tom Giebultowicz.

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