I am a retired developer (about 40-years at a keyboard) and have an SP2 running VMware Player. Not sure how battery friendly it is, but , the first thing I do with most software is to use WireShark and watch what it does after installation and during general running. Then I go to the Router and block any/all calls to the Software's-home. I use dd-wrt on my routers and "Drop" the CDIR in the Firewall.
Player specifically does a LOT of calling home so it is frequently very busy in the background. You could also check the TaskManager for CPU% use instead of using WireShark but then you would still need to know the IPs being requested.
Another thing I have found is that when using a second screen, it is FAR better to use the Display Port of the Surface rather than any Port replicator thingy (Dock etc) that uses DisplayLink drivers. The amount of continuous hard drive activity by DL 1.3 (current version) is shocking to say the least.
It all eats battery.