Your energy usage will be available in
- near real time
- near-real time
- near real-time
on your mobile.
Which is/are correct?
Wikipedia seems to suggest the third option is correct, near real-time.
While hyphenation is often arbitrary, I would suggest to follow the established usage in this case.
Having said that, in the same paragraph it also uses near-real-time:
...a near-real-time display depicts...
Here near real-time is used as a modifier of display, so the hyphenation clarifies that it is one unit, rather than, say, a near-real time display