wind farms - so reliable

The BBC reports that

A wind farm off the coast of Kent has suffered persistent mechanical failure in the four years since it began operating

Gearboxes in all 30 turbines on the Kentish Flats have been replaced with newer, improved parts.

In 2007, the gearboxes - which transfer the power from the blades to the generator - were all replaced because of bearing failures.

In 2008, 20 of them were changed again with an upgraded version, and now the final 10 are being upgraded too.

You could call it teething troubles if you wanted to but not really the reliable replacement for fossil fuels that they are made out to be, are they?