The Kia Optima PHEV shares the powertrain of the Hyundai Sonata PHEV, and like its sibling, it has a 9.8 kWh battery pack that delivers an all-electric range of 27 miles , but the Optima plug-in hybrid has a lower drag coefficient, which at 0.24 Cd is on par with the all-electric Tesla Model S. The Optima PHEV has an active grille, which automatically opens and closes at high and low speeds, contributing to reduce the Cd.