He will just end up using more chips and more electronic components and PCB to get to the same performance and since power use by any ASICs is already very low and cost per kW is not $4 but only $0.10-$0.40, there is no point in ruining chips at low power.
How do You get $0.1 ($0.4) per Watt ?
Residential rate in New York is $0.34kW, commercial rates in some places in US are $0.08kW