Is there any utility I could use to check how much energy a USB device is consuming, for a given time frame?
Unfortunately most if not all usb hardware does not have anything to monitor the current draw through it. You can find the max output of your USB ports in the documentation of your hardware. The standard is 500mA but many newer devices provide more for things like phones, mp3 players, and tables. The same can be done for your connected device. But this will be the max. It may not use that current all the time.
You have a laptop that has a max on EACH port of 1000mA. (some hardware max might be the total of all the ports or each port) You plug a phone that has a max draw of 2000mA. The phone will only be getting a max of 1000mA. However when the phone is done charging it might go down to something like 100mA.
The way you could accomplish this is using a patch cable to connect an ammeter to the positive line and then connect your device. But this is outside the realm of your question.