GPUs cost a lot to exploit a small price issue like this. I would use a dirt cheap heat element heater - presumably you could acquire these very cheaply and get paid to use power.
The problem usually is that there's a physical cap on how much energy can be transmitted through a grid endpoint, and grids themselves charge a significant portion of the bill, meaning arbitrage only works if the actual price is eg. -14c (the case in my particular location)
The problem usually is that there's a physical cap on how much energy can be transmitted through a grid endpoint, and grids themselves charge a significant portion of the bill, meaning arbitrage only works if the actual price is eg. -14c (the case in my particular location)