Whenever electricity prices go negative I have automations to force-charge my solar batteries from the grid, turn on hot water heaters in my hot water tank (normally heated by gas etc. ).
I just have Home Assistant turn on everything: dehumidifiers, heaters, lights, set the freezer thermostat to -25c.
So far I've earnt about 10p, but the real saving comes from having a little bit of thermal inertia to carry through to when prices are higher.
The market for power imbalance was already on 15 minute blocks.
I'm using a HomeWizard smart plug [0] to enable my electric boiler to only run during the cheapest hours of the day
You should absolutely re-run these numbers to be sure, but you might find you can use electric heating far more often than you might currently be doing.
There is an Octopus Integration that exposes current prices (and much else) to HomeAssistant.
There is another Integration that works with my solar panels and another that works with my batteries and can change mode (self use, force charge, force discharge etc.)
So from there it’s really just a question of setting up some if-then automations to turn on smart switches, charge the batteries if prices go negative.
You can also gradually add more nuanced automations like turning on water heaters if the panels are generating more than 1kW and the batteries are over 90% charged.
I’m not a programmer, it’s all fairly easy to do.