The C-Max Energi has an EV mode button on the center stack that lets the driver choose between three modes: electric-only driving, normal hybrid mode (which blends electric and gasoline engine power as appropriate) or EV-later mode, which reserves the battery pack power for later use.
Since the C-MAX Energi is more than just a regular hybrid, you can choose one of three different driving modes via an EV Mode button on the center stack.