But when is a miner who trades their mined coins taxed? Quarterly or annually?
It all depends on when the government requires you to file an income tax report. I am not familiar with your taxing Laws but income coming from cryptocurrency will always be included every time you will file a tax report.
Can you deduct electric from gross (or whenever)?
Are you running your mining operations at home? If yes then how will you separate your expenses on your electric bill that is not mining-related. It would be harder to do that as you are sharing the electricity from your mining equipment as well as your other electric appliances and amenities. Too bad your 1500$ bill cannot be used to deduct expenses in that way.