After green comes blue

What does blue energy mean?

This is called tidal energy.

It is a promising field, however, and one that has outgrown its infant stages.

the Technology Readiness Level (TRL) of this technology as “about that of the Brothers Wright when they flew their first plane.”[2]

Wright Brothers first flight


One design looks basically like an underwater wind turbine, the difference being that it is not the wind but the sea current driving the propellers.

Fully submerged turbines


Another approach is to capture the kinetic energy of the waves at the surface of the sea.

Semi-submerged wind turbines
The Pelamis Prototype machine at EMEC, Orkney, Scotland

Promising… But

Many things about this technology are still to be worked out, not least the materials to be used.

Challenging weather conditions

Such machinery would be continuously exposed to very challenging conditions and whether maintenance or repair work could be carried out in a timely manner would very much depend on the weather so it is imperative that they are designed to work as reliably as possible with as little interference as possible.

What about the marine fauna?

Another problem associated with such under-water power stations is that they must not interfere with the fauna (in particular whales seals) and long term evaluation programs are already underway.

Are wind turbines birds slayers?

One thing is certain:

Tidal energy is one of the greenest energies possible.

Even a massive tidal power station would be too small to significantly upset even smaller seas like the North Sea or the Baltic Sea.

What are the alternatives?

While some people still claim renewable energies to be unreliable because the sun doesn’t shine at night and the wind might not blow at all, tidal energy will always be available because for as long as the moon orbits around the earth the sea will ebb and flow.

The physics of tides

Blue energy is energy that is harnessed from the sea and it’s time to have that on the radar.



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