Paid Not To Use Periods

We are occasionally offered to be paid at a very tempting rate to reduce our power at specific times of the day. I have batteries and multiple very high consumption devices like Fridges, Freezers, air conditioning, heat pumps, and water pumps.

I already control most of these devices to optimize use of cheep overnight and free solar power, but I am very interested in extending that to make these devices use ZERO power when I am being paid to reduce consumption and many times the import unit rate.

Can ideally the local MQTT api (if not then the web API) include data that indicates that a "deal" period has started and what the payment rate for reducing power is?

I am not sure that the energy companies publish these data values but if they do please expose them to home automation users.