Energy Audits are important to save money and cut power consumption.
Have you looked at you company power bill lately?  Do you go home with all the lights on just like the plant was in operation?  If the answer is yes to any of these then you need to set up a meeting with your staff and the maintenance department.  Ask the people who are there all night doing the maintenance.  They will know what is needed and what is not.  The use of zone lighting or emergency lighting may be all that is needed.  HVAC may not be all needed when the plant is closed up or maybe the temperature can be turned up for A/C or turned down for heating.  The night shift crews will have the answer.  You may not always be able to do what is asked but it will sure help in the overall decisions to cut costs.