Answer: complexity
Explanation: In simple words, complexity refers to the characteristic of a phenomenon under which a subject becomes difficult to understand and use for the users due to its complicated in-built framework.
A complexity works as a hurdle in the promotion of the new product or service that is offered in the market. Complexity creates inferiority among the potential users regarding a technology which ultimately leads to the failure of whole project.
In the given case, people are concerned about the some concepts of electric car technologies ,means they are not fully understanding it, hence, we can conclude that the given case depicts complexity of the innovation.