Hybrid cars remove most advantages to IC engines as start-up and response times can be made irrelevant.  Further, cars generally only need a small fraction of engine max power hybrids also allow for heavy engines relative to HP as most cars can maintain highway speeds with less than 40HP.<p>PS: As to fuel vs. energy costs.  The vast majority of gas&#x27;s costs has nothing to do with direct energy costs.  Oil is already vastly more expensive than competing fuels so even a 2&gt;1 energy loss could end up less expensive than current production methods.