The ship was powered by a pair of three-cylinder vertical triple-expansion steam engines, each driving one propeller, using steam provided by 20 Belleville boilers. She was the last British battleship built with Belleville boilers as they had proven problematic and uneconomical in earlier ships. The engines were designed to produced a total of give her a speed of and "Prince of Wales" slightly exceeded this on her sea trials on 8 February 1908, reaching . She carried enough coal to steam at a speed of .