Metric units are used for all measurements.  

Kilogram = kg
Second = sec
Meter = m
Squrae meter = m^2
Cubic meter = m^3
Kilometer = km
Square kilometer = km^2 = 10^6 m^2
Cubic kilometer = km^3 = 10^9 m^3    
Watts = W                                               
Kilowatt = kW  = 1000 W                                                                      
Megawatt = MW  = 1000 kW Gigawatt = GW  = 1000 MW

Million = MM