Hybrids are generally significantly more efficient that ICE cars because it keeps the engine in the "sweet spot", efficiency-wise. If the sweet spot for engine

Hybrids are generally significantly more efficient that ICE cars because it keeps the engine in the "sweet spot", efficiency-wise. If the sweet spot for engine efficiency is more power than you're using, then the extra power goes towards charging the battery. If the sweet spot is less power than you need, it can make up some of the difference with the electric motor using previously stored power. People talk a lot about plugging them in, or regenerative breaking, but that's overlooking the main way they work, which is in concert with the ICE to make it more efficient. (caveat: I'm not an expert, but own a hybrid and had a long discussion with an engineer friend who had just taken a hybrid powertrain class)