Rice University group presented a paper on Google Glass power consumption breakup at Asia-Pacific Workshop on Systems 2014 (APSYS) at Beijing, China:
"Draining our Glass: An Energy and Heat Characterization of Google Glass"
Robert LiKamWa, Zhen Wang, Aaron Carroll, Felix Xiaozhu Lin, and Lin Zhong
The power is by far dominated by camera and image processing:
The same is seen in the temperature profiles: