There's a few options here:

One, energy costs just recently went up a bunch. Everybody's getting much bigger bills than before, so it could be that, and we're just getting used to it.

Two: If this is a single month spike payment, it could be that CMP, for whatever reason, couldn't get to your meter to read it. They'll then estimate your power use for the month, and tend to estimate HIGH. You'll get a credit the following month when they get the actual reading.

Three, you could actually have an appliance that's sucking up a lot of juice. CMP does have an energy meter log that can show you how much juice you've been using per month. If that's suddenly spiked, you want to check your appliances. Electric water heaters, space heaters, and pumps (Well or sump) can all end up running constantly when something fails or is forgotten, and will gobble up juice when this happens.

Four, as I don't know Nautilus, make sure your agreement with them didn't include any extra fees or charges, particularly for the first X months of signup sort of thing.

Those would be the possibilities I can think of.