Tidal Power Then and Now

A while back I wrote a post on Tidal Barrages (https://lifekills.wordpress.com/2009/02/13/tidal-power-barrages-and-ebb-generation/). Here is another way to generate energy from tides.

Probably, everybody is aware of possibilities of energy production in case of extinction and depletion of fuel deposits.  The solution is found in renewable energy due to multiple opportunities provided by natural and environmental conditions. Tidal energy is the one secured by both cosmic gravitation of the Sun and the Moon, and oceanic spaces, of course. However, not all the regions on Earth can boast of favorable and promising tidal indicators. That is why it is better to feature on France and the English Channel as an area where tidal energy generation was organized for the first time and where the most powerful tidal station is going to be constructed this year.

It is interesting to know that the first registries of tidal energy usage are dated back to the 10th -11th centuries. There were lots of windmills and sawmills in England and France, which used tidal energy in industrial purposes. However, only one of these two states might be marked with erection of the first tidal energy system in the world. It was Rance Tidal Power Station, constructed on the estuary of Rance River (Brittany Peninsula) in 1966. Its capacity is pretty astonishing – 240 MW produced by 24 tidal generators, – which is preconditioned by comparatively high tides reaching 13,5 meters. The significance of Rance station is still of high value even nowadays, contributing 0,012% to energy demand in the country. Most of the power generated by the station is used during peak seasons (544 million kWh per year in total). However, high prices obstruct the enlargement of tidal energy industry. Speaking of energy production in France, nuclear power production keeps the lowest cost. In this case, the renovation of the Rance station is getting more appropriate and promising.

On the contrary, in 2012 Frenchmen might see the most powerful tidal project actualized. In particular, it is associated with the station near the coast of Paimpol-Bréhat in Brittany. The project was assigned to Irish company OpenHydro Group Ltd. and French company EDF, which already accomplished some magnificent and profitable projects on tidal energy in North America and the United Kingdom. Paimpol-Bréhat power station was designed in 2004 (estimated cost was 55 million dollars) and in 2008 the construction was started.

The basis of new tidal station is comprised of four large turbines with a weight of nearly 850 tones each. They are going to be established near the coast, attached to an anchor on the depth of 115 meters. The diameter of each turbine is 21, 5 meters. It is appropriate to note that tidal turbines have certain advantages in opposite to wind and solar cells, including invisibility under the water, quiet operation and less impact on environment. And, besides, a new station can provide energy for more than 4 thousand houses in the region of Paimpol-Bréhat.

Maria Kruk, an author for Patentsbase.com

Tidal Power barrages and ebb generation

marine_tech_018

It’s such a simple concept I wonder why it’s not a “popular” idea for alternative energy.

Exploit the difference in potential energy between high tide and low tide.  Dig a ditch or basin into a beach or cliff and then make a dam with flood gates and put some turbines where they will be turned by releasing the trapped water.

The main advantages of this kind of tidal power vs the more popular idea of turbines trapping underwater currents are environmental. When we look at the design of these windmills under the sea, they are very similar to food processors in that any wildlife coming close will be chopped into slurry.  Not to mention the fact that they would only capture a small fraction of the tidal power compared to a tidal barrage.

It is important to distinguish between tidal barrages created on rivers or estuaries and totally man made barrages.  The former types of barrages have the same kind of environmental problems because they interfere with extablished marine ecosystems.  Creating a new inlet would allow for a screen-like divider that would exclude animals that could be harmed by the turbines or other mechanisms.

The potential is almost unlimited for countries like the united states due to our extremely large coastlines.  The construction of these barrages would also creates lots of jobs a la the Obama plan for saving the economy. 

In the coming years we will have to make important decisions about which technologies we chose to implement for a sustainable future.  If we choose without full disclosure as to the dangers and benefits of each technology, the results could be disastrous.  If we were to make huge investments into bio-fuels instead of more truly sustainable technologies, at some point we will have food and water supply problems.  I understand the appeal of bio-fuels because they use already existing technologies and thus can be immediately implemented.  I also understand the desire for a quick fix but long term thinking is the only way we will survive peacefully into the next century, after oil has run out.

Radiation from the sun, Gravitational pull from the moon (ocean Power), Geothermal from plate tectonics and volcanic activity, and wind power are the areas we should be putting massive investment into.  Other technologies may serve as a fine transition between fossil fuels and true sustainability but we must plan for the long term using inexhaustible sources of energy.

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