Can I disable Nvidia graphic card for improve battery life?

Hi.

Im thinking of buying a laptop for my job (security consultant). I want to install a Ubuntu or Debian distribution (and maybe Windows too, but for normal use Linux).

The problem is that I want a laptop with a good battery life, but with good graphic card. Im interested in a Dell Vostro 3000 series:
- Intel i5-5200U
- 8gb RAM DDR3L at 1600MHz
- NVIDIA® GeForce® GT 820M
- Hard drive 500GB at 5400 rpm

I think about it, and the problem is when I use that graphic card, the battery consume is faster, but I need this graphic card for some tasks. The question is:
Is possible to, when I need more battery life, disable the Nvidia graphic card and use Intel HD graphic card? In that way, I can save more battery.

So please, if it is possible, let me know if this is a good laptop for this. And if you know other laptop for the same price (around 700 euros), tell me.

Thanks for the help