A full-size grid-tied solar array with about 15 or 20 panels can cost anywhere between $25,000 and $40,000 upfront depending on the size. AC panels are not cheaper, but proponents say the modularity makes it easier to install a few panels, and then later connect more to the existing set. More flexibility.
Evil, in a general context, is the absence or opposite of that which is described as being good. Often, evil is used to denote profound immorality. In certain religious contexts, evil has been described as a supernatural force. Definitions of evil vary, as does the analysis of its motives.
To say that a spirit is evil or harmful or bad is saying that it has no free will to act haphazardly. Although some humans seem to be almost purely evil, and some humans almost always attempt to do good, the vast majority exist in the middle ground.