Commercial 'maximum demand' pricing has been using half-hour segments since the 1970s and probably before. This is hardly a new model, just something that has now become more possible for smaller customers.
I write software for micro based systems for reducing maximum-demand back in the 1970s.
The charging algorithm then was quite simple, you got charged for the units you used and you got charged for the maximum rate at which you used electricity (per half hour period). I.e. there was a charge based on the maximum consumption in any half-hour period over the charging period which I think was at least a month and possibly a quarter.