Make my company green by making others less green.
The Niagra hydro power stations have been around a while, providing NY State, Ontario and others with power, but their output is finite, so if Yahoo! takes the power, then less is available for others, so theirs have to come from other sources, maybe green, maybe not.
Although one might say the closure of HSBC's facilities would balance that.
I have noticed a tendency for companies to open new "Green" facilities that reduce their carbon footprint by increasing those of their employees. That old energy inefficient office next to the station, replaced by the low rent, green field offices with low energy consumption that are nowhere near any sensible public transport, so everybody that used it before now has to drive.
Then there's home working, which means less energy consumption in the energy efficient office, and more in the inefficient home, although at least you don't have to drive to the office, except that rationalisation has closed the local one anyway, so that instead of a 15 mile drive, or a train journey, you now have a 75 mile drive twice a week.
Still at least the company is meeting its targets.
(BTW this scenario actually opened an office near my home, on the bus route and by the train station, except that I was posted to one 60 miles away instead)