If you listed it as a side business you should also be able to deduct the electricity expense (and the cost of the GPU, depreciated over some expected lifetime)

If you listed it as a side business you should also be able to deduct the electricity expense (and the cost of the GPU, depreciated over some expected lifetime) as a business expense against the revenue you made from mining. You pay income tax on the crypto when you mine it at the market value at the time of mining - then your cost basis becomes the price that you paid (for future gain + loss computations). The reporting requirement is quite annoying, so for a single card/rig it's probably not worth it - but should still make money. There shouldn't ever be a case where you have to pay more in tax than you made mining (with one exception: you keep your mining income in crypto and the crypto tanks).