You can blame Facebook for much of this green datacenter hype--some of which is arguably greenwashing.
Facebook was under the gun for opening its own data centers that were, and still somewhat are, powered by electricity generated by coal.
To answer this unwanted attention they bent over backwards to reduce power consumption at all costs, so much that they even designed their own "Open Data Center" servers to reduce power consumption at the cost of discarding nearly everything we already know works fine in conventional data centers.
And, to top it off, they greenwashed by buying carbon credits and energy that appears to come from non-coal sources.
Google and Microsoft are doing this the right way. Data centers should be in cold climates and supplied by truly renewable power.