> Hardware for mining cryptocurrency is self-financing in a relatively short period of time when the electricity is "free"
No it isn't. I know because I looked into it.
Assuming the price of bitcoin doesn't rise or fall, a cutting edge bit of dedicated bitcoin mining hardware will pay for itself in 3 years if operated continuously on free electricity, and will be effectively obsolete in 5 years, as difficulty increases and rewards drop.
So if you only operate the hardware 50% of the time it'll be obsolete before it's paid for itself.
That's because you're using Bitcoin, for which custom ASICs are a thousand times more power efficient than commodity hardware and so commodity hardware is useless, but custom ASICs are stupid expensive.
What you want is a cryptocurrency that ASICs are no better at than CPUs or GPUs, so can use an ordinary CPU or GPU that will pay for itself more quickly because most of the mining cost is electricity instead of hardware. (Hint: the hardware you want in this case has the best performance/$, not necessarily the best performance/watt.)
"Which cryptocurrency" will also vary over time since the prices are all over the place, but that's the other advantage of not-ASICs. You can switch to whichever one pays better this month.
No it isn't. I know because I looked into it.
Assuming the price of bitcoin doesn't rise or fall, a cutting edge bit of dedicated bitcoin mining hardware will pay for itself in 3 years if operated continuously on free electricity, and will be effectively obsolete in 5 years, as difficulty increases and rewards drop.
So if you only operate the hardware 50% of the time it'll be obsolete before it's paid for itself.