Nowadays, the price of oil is higher than it has ever been before.
The price of oil is higher than it has ever been.
You don’t need to say “nowadays” or “currently” in situations like this. If you simply state your idea without a time mentioned, readers will assume you mean the present. If you meant twenty years ago, then you would say so. You can also leave out the “before” at the end, because it has no effect on the meaning.
You could make the sentence even shorter, as in: “The price of oil is higher than ever.” But I like this sentence less. It sounds slightly informal to me. Writing concisely means eliminating unnecessary words, but that doesn’t mean making every sentence as short as possible. You also have to consider other values, like the tone of the writing.