The key is to see the blades of a turbine as a sail being tacked along a constrained course, or to recognize that a windmill generates energy that can be put to many uses. Even then it takes more words than we have room for here, but be advised that your correspondent has, acting in good faith as an official observer for the North American Land Sailing Association, signed a recommendation for certification of a dead upwind record at 2.1 times a true wind speed of 9.9 mph. I expect ratification by the time you read this.
It was June 16 at New Jerusalem airport, California. Rick Cavallaro, chief scientist at Sportvision (the sports graphics company founded by 2010 Rolex Yachtsman of the Year Stan Honey) used a re-configured version of the vehicle that in 2010 went dead downwind, using only the wind, at 2.8 times the true wind speed. According to Cavallaro, “It was all inspired by people telling us it was impossible.”