Mean Green Mowers introduced the Evolution Lithium-powered electric commercial EVO-72-inch ZTR mower. New for 2019, the Evolution can mow for up to 9 hours (depending on battery pack size). According to Mean Green, the Evolution offers five times the power of previous Mean Green mowers, and features an aluminum frame for lighter weight and improved efficiency. The Evolution travels up to 12.5 mph, and is comparable to a 38-hp. engine.