One of my favorite quotes from the Simpson’s is this one

Homer: In this house, we obey the laws of thermodynamics!

The law which he is referring to is that energy cannot be destroyed only changed from one form to another. Basically you can’t make energy. Hence why Steorn could not get their perpetual motion machine to work. This is why renewable energies are not really renewable. They are simply not reliant on man for the energy. Take solar power. The energy that uses comes from the sun. Like wise wind and biomass derive their energy from the sun.

But what of tidal power?

At the moment they are building one of the largest tidal power plants in world in Strangford Lough County Down. Basically how it works is it uses the force of the tide going in and out to turn turbines. This is not a very new idea. In France the Rance Tidal Power plant has been operating since the mid 60s Producing 0.012% of France’s electricity use. Producing 600million KWhrs a year. (Ireland uses 22.97 billion KWHrs a year.  So a similar plant in Ireland would supply 2% of ours)

So where is the conservation of energy in this system where is the loss of energy in this system. Well it comes from the Moon and the Earth. How tides work is that the moon is on the same axis of rotation as the earth. Therefore is pulls the water from the earth in line with the axis of the moon to the Earth. Giving is high and low tides depending on the position of the Earth. Now this is not a lossless system. There is energy lost in this process. (for instance sound of tide lapping on the shore but friction underwater mainly).

As this energy is lost to conserve energy an interesting thing happens. Tidal Acceleration. The speed and distance of the moon increase and the speed of the earths rotation decreases. There is geological evidence to support this 620 million years ago: the day was 21.9±0.4 hours, and there were 13.1±0.1 synodic months/year and 400±7 solar days/year. Now this is of course a small effect. 620 million years is of course massive.

But what has this got to do with tidal energy. Well as you might imagine the taking of energy from the tides is going to add to the energy loss in the above system. French Scientists have estimated that if tidal was used at a large scale rate. Then the earths rotation would slow down by 24 hours every 200 years. That is quiet a lot when you think about it remember it took normally 620 million years to drop 3 days. So if you are one of these people who think there is not enough hours in the day say it load say it proud.

MORE TIDAL PLEASE.

(just don’t expect to see the results)