I get a few questions my way on an almost daily basis about how writing code using C++ results in savings in power consumption and other performance benefits. In this regard, I defer to the experts (Bjarne, Sutter etc) who explain these concepts with much more clarity and authority. So here you go:
http://www.noodle.org/learn/details/115493/bjarne-stroustrup-how-c-combats-global-warming
http://channel9.msdn.com/posts/C-and-Beyond-2011-Herb-Sutter-Why-C
Enjoy!
-Sridhar