That just shows up as a constant factor, accounted for at build out. Consider if each watt dissipated required an additional watt. That's clearly an absurd overestimate yet it would "only" double power costs making the example $2800 / year. Underestimate the B200 at $30k USD and you've got 10.5 years of operation before you achieve parity as a fairly unrealistic worst case estimate. Now consider that at a 9% failure rate the average lifespan is only ~11 years. So electricity (both operation and cooling) is pretty much guaranteed to be less than half your total operating cost no matter how you slice it.