Energy consumption *could* become an issue? 
Energy consumption is a huge issue.  Some key facts which prove humans are extremely stupid:


1) More than half of all hydrocarbon energy of our spaceship earth already was burned off with no attempt at use or capture ("natural gas flaring").

2) Continued pouring of energy as visible light away from Earth at night for no fucking reason at all (see pictures of the Earth from space).

3) Horrendous inefficient use of energy for transport, including millions of folks bringing 2 tons of steel huge distances every day with them.

4) So-called "defense" or "military" using energy just to destroy other energy, in efforts to demonstrate how psychotic they are so other folks will be afraid of them. 


Yes, piss-poor use of energy resources is a *huge* problem on spaceship earth right now.  No, proof of work networks don't add meaningfully to the total.  But yes, it is something we should think about, so my apologies for getting upset.  It happens whenever the topic comes up.