Offshore energy sources and climate challenge - Part 2 - Blades’ crash and the towers distorted at random

Crashing the blades is a typical problem of shore wind turbines, while offshore turbines work in more hazardous conditions and rarely face that problem.The problem usually occurs in the farther part of the blade when it has the minimum potential energy of its cycle e.g. at the bottom of its course rotation.

At this specificposition the bladeis reaching themaximum of its complex load composed bygravity, driving moment, groundturbulence, electrostatic chargeetc.

When spinning, the blade is carrying a high positive static charge, while the tower is negatively charged.Out of that potential differencean attraction effect appears between the blade and the tower.

This effect simultaneously and repeatedly increases the outward from the blade rotation centre and the pulling out from the tower.

In addition to that the tower is creating onemore stretchingchallengefor blades by essentially changing the air stream at its bottom.

So far the conditions are mostly the same with offshore wind turbines but whydooffshore blades crash less often then shore ones?

What is the difference?

I would say the dust and the additional static chargethat comes from it. Dust is rather less common over the sea.

Shore high windscarry a lot of extra dustwhich results in a positively charged electrostatic pillowto dohitthe blade at its potentially criticalbottom position. This additional load greatly contributes, in my opinion, to the higher probability of shore blades crashing.

The complete transition process supposes to be a topic of other release.

Let’s come back to solutions.

There are a couple of standard solutions on how to reduce or eliminate above described extra static load on shore blades but the most effective way to spin wind turbines at higher frequency during increased wind loads is a new style of development.

For example: After fixing the general problems of bladesby standard and non-standard solutions they may spin with frequency triple than current. Then what about the towers?

One thing about the towers, they might stay straight against the wind but not like now.

Here we go to set against the wind ? new development style - “The towers distorted at random”.

See the nature: Distorted trees remain after the gale.

What would be the future for shore and offshore HAWTs and VAWTs depends of our imagination.

Help in text edition: Simeon Azarov

Sofia University “St. Kliment Ohridski”

Faculty of Physics, Dept. NE student