How to process energy (kWh) meter reading data of half-hour interval
I gather the purpose of statistical analysis here is to define the rate of peak Power demand during daily and seasonal diurnal loads, so kWh would not apply as the duration of Peak power for different times of the day or week or weekend.

These peak durations of interest will be much less than a hour yet the grid must be maintained dynamically ( impedance of net sources) to supply this peak power on demand and stay within specified voltage tolerances.


  If the meter reports kWh in 30 minute intervals then you use the average energy per reading  kWh x2 = P per 30 minute reading.