[OJFord]

In the UK 'variable rate' tariffs are common, usually updated monthly.

Octopus' is daily, and also offers an hourly plan 'Agile' with an API.

There is a regulatory cap on the cost of energy, which is a bit convoluted, but Octopus passes it on as a 35p/kWh cap on variable rate plans.

[thayne]

A price that changed monthly might be manageable, but daily or is probably too much for most consumers to keep up with.