You can measure power movements at a macro scale. So you can see how much energy is being produced by power stations, and how that’s being fed into distribution

You can measure power movements at a macro scale. So you can see how much energy is being produced by power stations, and how that’s being fed into distribution networks, plus you can sum all the power usage going through end user meters. All that together give you enough data to pretty accurately estimate stolen power. But not enough data to figure out with any precision where it being stolen. You might know that certain parts of a city are worse that others, but you couldn’t identify the house or even road where it’s happening.