What is an alternator, and what is a generator?

"Alternators and generators are both technically generators, but they operate differently and are usually used for different types of projects. Alternators create and store energy, only using what's necessary, while generators convert one source of power into another and don't store any excess energy. Alternators are best for small-scale projects, while generators are best for large-scale projects. I understand that your company works with clients that are typically seeking large-scale solutions to their engineering problems, so most projects probably incorporate generators over alternators."