5G...has a generally quite high power consumption.
5G is not correlated with "high power consumption." In fact, one of the main goals in research is lower battery (power) consumption. In the past it might have been okay to blast power in all directions to make sure you are heard. Now, there is too much demand so we invest in technologies such as small cells to reduce power levels/interference and increase capacity.
5G is really all about efficiency, using our limited resources in a smarter manner. How can we increase spectral efficiency (stuff more bits per hertz)? How can we get more spectrum (see millimeter wave and FCC NPRMs)? How can we share more efficiently (see 3.65 GHz CBRS use of dynamic frequency allocation via SAS).
It even comes with softer questions that aren't as technical, such as "how can I quickly get permission to mount antennas in peoples yards (NIMBY issues)?" and how do I get fiber ROW?" since again there is no spectrum for wireless backhaul.