Load Profile plot from Smart meter data
You can plot the difference between any two readings, divided by the time between them. This gives the average load during that period.

Just keep in mind:


You only get average power over 30min, no shorter peak values etc. 
If power consumption is low compared to the resolution of the read out numbers, you get some aliasing effect. Imagine a device drawing 1kW constantly. If the smartmeter has a resolution of 1kWh, you will get interleaved load values of 0kW and 2kW. You might get around this by averaging over consecutive readings. If power consumption is even lower, it might be better to look at the time beween two changes in read value.