Bearings: The Achilles Heel of Wind Turbines.

A few years ago, I used to know a senior wind turbine engineer. One evening, over a few beers, he told me the dirty secret of his profession:

“The problem is the bearings. If we make the bearings bigger, the bearings last longer, but making the bearings larger increases friction, which kills turbine efficiency. But we can’t keep using the current bearings – replacing them is sending us broke. What we need is a quantum leap in bearing technology – bearing materials which are at least ten times tougher than current materials.”

Us electrical engineers have the same problem, heat (temperature actually) is a life killer. We try to avoid using components at their maximum rating. Because with that rating comes a life. And life is an exponential factor of temperature. The rule of thumb is that a 10°C rise halves the life. It doesn’t take too man halvings to have very little useful life.

It any case – wind turbines. Evidently they are not quite fully paid for.

Further, I worked on a magnetic bearing project back around 2004. They have zero metal to metal contact. Which is a good thing in some cases. But they do have energy losses. And I don’t think they are yet up to supporting wind turbine blades with acceptable sizes and losses. And they require a control system. If you are interested in a control system see the “Further” link above.