It's an idiomatic thing. When we're speaking about the elections, we don't think of it as "an" election. It would be odd for us to think of it as "an election among many others" since it isn't. Instead, we think of it as a state of affairs. Much like we say Det är sommar, 'It is summer', Det är kväll, 'It is evening', without articles.
Technically it can, but I would say "equally well" is a bit of an exaggeration. As a native speaker I 100% interpreted this as singular, the possibility of plural didn't even cross my mind. So I wouldn't call this sentence ambiguous even if it could technically mean both things.
In American English at least, we sometimes refer to year in which the quadrennial presidential election occurs as "election year." So if i wanted to specify that i might say "this is election year," or "this year us election year." But we have so many levels of government that we're almost always electing someone or voting for something.