Non-subsidized electricity costs between 17 and 22 percent more than normal rates.
Ideally, subsidy is an emergency help. That is, it should not become a permanent policy. But the fact that people perceive non-subsidy as not normal is a reflection of thinking the other way around.
Without altering the meaning, I could have written, otherwise, as follows:
Subsidized electricity costs between 17 and 22 percent lower than normal rates.
Wait, maybe it does alter the meaning.