Exponential growth means Microsoft will be buying counterfit offset certificates
Say data use grows by 2.6x in two years and equipment becomes 1.6x more efficient then after two years 50Mwatts becomes 80MW after four years becomes 130M, 210, 340, 550MW after ten years. By then the wind potential of the county could be all used up. But there will be more green energy.
Using MSs approach paper credits will rise in price and the market for credits will boom i.e. rise much faster than linearly. Unless MS services achieve monopoly in ten years its energy costs will put it out of business. Look for MS to take a longer, more googly, approach soon.