Climate change: We give one of largest onshore wind farms its MoT'

Wind farms, like any other technology in constant use, require regular maintenance and lots of upkeep.

And none need it more than Pen y Cymoedd - the largest onshore wind farm in Wales.

With 76 turbines in operation at the site near Treorchy, Pen y Cymoedd is capable of generating 228MW of energy - enough to power 15% of homes (188,000) in Wales.

BBC Wales News took a trip up one of the farm's turbines to see exactly what's involved in keeping it up and running.