From my experience, the newest VMWare versions and Linux kernels are very good at conserving power when the VM is mostly idle.
I'm doing on that my 2014MBP, and it didn't cut the endurance to half, but need to re-test it for exact numbers. However, it doesn't appear in "power hungry applications" list unless you continuously compile something or run some service at 100% CPU load. Also, you can limit the resources it can use if you want to further limit it down.
Because I'm using my laptop to, well, work on the go a lot; this is a showstopper.