C-MAX Energi operates just like a traditional hybrid with two key differences - owners must plug in the vehicle using its charge port and C-MAX Energi has a larger battery pack.

ENGADGET: Ford's 2013 C-Max Energi rolls out 95 MPGe, arrives later this fall

Ford calls C-MAX Energi a "hybrid-plus" because it not only operates just like C-MAX Hybrid, but also features an external charge port and larger lithium-ion battery pack so owners can plug in the vehicles to fully charge the battery using either a standard 120-volt outlet or the available 240-volt charge station.

ENGADGET: Ford C-Max Energi pricing: $29,995 after a federal tax credit, available this fall