Use only external display without closing monitor

I was wondering if it's possible to use only external display without closing the monitor - but, at the same time I would like to not use the monitor. The external display should be the primary+only display.

I am trying to do this because I am worried about my retina display getting damaged when it's in the closed-clamshell mode.

I am okay with having my MacBook plugged in to the charger all the time.

But, it would be even better if it's possible to turn off the charger, but I don't think that's possible at this time - am I right?