For the first time, PwC used a drone in an audit to assess the value of inventory, in this case, coal inventory for the German energy giant RWE in Aberthaw, South Wales, the firm says in a statement. The traditional method of hand-counting inventory would have taken four hours, but the drone captured 300 images in 30 minutes, a reduction in time of 85%, the firm asserts. The images were used to create a “digital twin” of the coal pile to measure its volume. The value of the coal was then calculated to within 99% accuracy. “Sectors with large assets in hard-to-reach areas are the most obvious starting points for expanding this kind of work further—from mining to agriculture and forestry,” says Elaine Whyte, U.K. drones leader at PwC.