Our electricity consumption is monitored near real time and is available on eloverblik.dk
Where you can log in to get a collective exact overview of import and export for every property you own or rent.
There would never be a requirement of documenting it, because any energy company that would require that info, you would grant access to it, so the can read it automatically.

So here by far the most normal is to pay by the hour, but we do not have credits for reduced consumption, which also IMO sounds a bit stupid, because the reduced consumption would just become the new normal.
So I’m surprised you claim it’s widespread.