Hybrids are more efficient than comparable conventional vehicles, especially in stop-and-go driving, due to the use of regenerative braking, electric motor drive/assist, and start/stop technologies. Still, much of the energy is lost to engine and driveline inefficiencies or used to power accessories. About 25%–40% of the energy from the fuel you put in a hybrid is used to move it down the road, depending on the type of driving.
Energy Losses and Gains for a Hybrid Vehicle for Combined City and Highway Driving
Energy Losses and Gains for a Hybrid Vehicle for City, Highway, and Combined Driving
Note: The figure is primarily showing losses, but the regenerative braking gains are shown below 0%, offsetting some of the above losses.
|Types of Driving|
|Types of Losses||Energy Losses|
|Parasitic Losses, e.g. water pump, alternator, etc.||4-6%||5-7%||2-4%|
|Power to Wheels, dissipated as:||27-38%||25-40%||29-36%|
|Types of Gains||Energy Gains|
Source: U.S. Department of Energy and U.S. Environmental Protection Agency, Fuel Economy Guide website.