The following is a sample code for measuring a power consumption of the circuit.

.param SUPPLY = 2.5
.meas TRAN CURRENT INTEG I(vVDD) FROM=0 to=4ns
.meas tran POWER param='SUPPLY*CURRENT'

The first line defines a constant named SUPPLY.
The second line measures the total current across the voltage source named vvdd for the time period from 0ns to 4ns. The result will save it into the variable named CURRENT.
The last line calculates the product of SUPPLY and CURRENT.

Note that all the capital values are dummy variables. You can named them whatever you'd like.

Please remember to set SUPPLY=1.8 if you were using the 180nm process technology.

If you need the average current through the circuit, spice has an AVG option for the .meas statement as well.