Assuming that you're not interested in the current consumption of the NAND gates, there are 4 ways the power can go, and you need to add them up.
1. Oscillator consumption from data sheet
2. Power to charge and discharge the 7 pF capacitor at the frequency of the oscillator
3. Current through the variable resistors.
4 . Current taken by the comparator
No. 3 is interesting. If there are two variable resistors, if they are both turned to minimum resistance then the current could be quite large.