Can someone possibly work out, when the break even point would be, when the miner reward & fees will not be enough to sustain the cost of mining. I have heard that +/- $200 per Bitcoin is about the breakeven point for mining to still be profitable at today's exchange rates.
I know there are a lot of variables, but it would be interesting to have a broad idea, even a guess at which point mining would not be profitable anymore. < Work on averages, if you really need to >
there is a part of speculation called a resistance point. this is the lowest point the price can get to before the majority of people refuse to sell any cheaper.
though people in general buy and sell at different prices (speculative area) there is always a bottom line where the majority resist selling.
after looking at the charts and doing some other maths based on known manufacturing costs(not retail) of asics, electric etc, and putting those numbers against the hashrate. and also doing this for the historic data.
right now the resistance point is over $480
EG
in 2011, speculation went up to over $32 but the resistance point was about $2
in 2013/14, speculation went up to over $1000 but the resistance point was about $200
this year speculation is at over $700, but resistance is about $480.
prior to the halving, it was around $600 speculative high, and $300 resistance point.
so now you know the area of speculation vs resistance (profitable area). you then have to look at the mining specifically.
some farms like antpool have no upfront costs. yes thats right zero.
this is because the manufacturing costs of an asic(bitmain) is far lower then the retail price they sell to competition.
its been worked out bitmain for every asic they sell retail, can actually produce 4-5 rigs for that single unit retail price.
they can either
hand one to the customer and keep 3-4 to themselves to run.. and then use the reward for paying bills
or
hand one to the customer produce 2-3 for themselves to run and then put ~$400 towards electric (2 rigs electric over 6 months ~$400)
basically it boils down to electric cost.
which i done the maths ages ago in regards to the bitmain S9 (13thash, 1.3kw/h) unit
one asic
at 20cents/kwh for 6 months electric = $900
at 10cents/kwh for 6 months electric =$450
at 5cents/kwh for 6 months electric = $225
and the $1600 to buy an asic
anyway, im now going to use round numbers just to get the point across ASAP. (someone else can be more refined if they want)
so knowing asia is about the 5c/kwh and antpool costs $0 for the asic. makes the 'cost' of mining by bitmain/antpool $225 per asic required ATMOST over an expected 6 month period. (i say atmost due them able to repay the electric at no cost thanks to retail income. but lets stick with $225 costs)
at 125,000 asics antpool have. and a ~18%(over 6 months) of blocks solved by antpool = 4700 blocks =~59000btc
which makes 0.471744btc per asic
which at current price value is an ROI of over $330 per rig right now.(based on a $700/btc valuation)
which is profitable compared to their $225 'cost'(electric explained earlier)
but say an american miner buying a $1600(retail price) and then paying average american electric for 6 months $450(10c/kwh) totals $2050 upfront.
but as i have just worked out the average btc earned over 6 months per rig is 0.471744btc ($330 per rig right now, based on a $700/btc)
so americans are not profiting. infact they are at a 83% loss right now.
summary.
throwing all the numbers together..
for antpool (lowest cost) to remain in profit btc has to be 1btc=$476 (where the mining income of 0.471744=$225 cost)
but as i say the costs can be lower if they prepay the electric via the competition buying the rigs
americans(retail purchase priced rigs) will only break even if bitcoin was $4345.
so asia can sell right down to $476 and break even
america wont sell and wait for speculation to jump to well over $4000 before selling. or be dumb and sell at a loss.
hope this helps