I'm on an unrestricted variable electricity tarrif.
My price per kwh is about to go negative for 3 hours*

I can get my oven and air con unit to fight each other, and be paid for it!

*it's so windy that there's nowhere to put all the energy the turbines are generating, so they pay (mostly industry) to use it up. The price shoots up in the evening when everyone starts putting their heating on and cooking dinner. People on a fixed price tarriff are paying ~25p/kWh all day in the UK right now.