you still miss the main problem as most Chia dreamers 
you can plot how fast you want - it still takes 4-12min to store plot to final HDD or average 8min/plot. Thus, you are limited to 180 plots/day/hdd. you can still fill just 1x 18TB/day if lucky
storing on SSD that cost 3-10x more per TB is fools game. If you have resources to buy 15$/TB, it is 6years ROI just hdd. Rich people are rich for a reason. No sane person invests for 18-60years in something with questionable future.
I have 48x hdd consuming 300W or 6.25W/disk…you are lucky, the part of Swiss I live in charges us 0.31CHF/kWh…and we have own hydro energy built by our taxes ROFL
We run most efficient farm/plotter so far we have seen there - based on data supplied by other guys in forum…yet, it is just a hobby to support future. You cannot make living from it…even, if you are poor guy from Swiss earning 5000CHF brutto 
Assuming your wife, won’t kill you…and you are allowed to do your little hobby. You would need 18 PB to quit your job…you would also need 7.5kWh grid connectivity…usual house/flat have two circuits 230@10A or 4.6kWh. Not to mention 270k just for HDDs 
As a hobby person, it may be possible if you can do it smart/efficient…can you imagine to manage 1200 HDDs?..40+ dBa noise…space 
Based on your example…I have server hosing at Hetzner…they have enough resources. They pay 0.49€/kWh. If you have computing power, you do not waste it
You will earn more money by renting computing resources/space.
Imagine what Google, MS, IBM, Amazon, BackBlaze, Pure Storage have…if it would make money…they would do it already, and we would be obsolete…The usual 500TB hobbyist would whine about poor earnings.
If you must pay employees, invest thousands into HW…it makes no economic sense. As a small guy, playing with few HDDs…it may be decent pocket money for kids 