Maxed Out Energy / Ecology values
This thread on BGG suggests a co-designer has clarified that -7/+7 is not a hard limit.  I couldn't find the exact post to clarify that but one of the designers has been very active answering questions.

Something in the rules here say is.


  Note: at any time, the players can recalculate their energy and
  ecology totals to check that they haven’t made a mistake


This to me would imply that you can move beyond -7/+7 as it can be recalculated at any time.  If you stopped moving at the extremes then its possible that the total couldn't be calculated in retrospect.