These days, giant wind turbines are supplying more and more of our clean energy. And when they break down, they need to be fixed fast. It's a job only a few people are equipped to handle. Those who are afraid of heights need not apply. Rock climber Jessica Kilroy, for one, loves the challenge of blade repair. And though she makes dangling at dizzying heights look easy, her path to becoming a wind turbine technician has been anything but that.