They do use a winch that gets them up a couple hundred feet or so - it’s technically not energy-free, but it’s pretty darn close to it. It basically shortens the initial climb and makes it easier since they basically have to find a thermal to gain altitude. So having a couple hundred feet to play with means they can fly around to find a thermal.

So they could take off without the winch, but it helps. But it’s such a minimal amount of energy that while it technically means not quite energy-free, it’s pretty darn close.

And once they find that first thermal, it’s certainly energy free for as long/far as they can go, which can be hundreds of miles.