Hopefully the local electric utility folks will be able to assist in a design. I say that with caution. A few years ago the local power company offered a free energy analysis of my 5600 sqft building. The power company guy brought along private contractors for the survey (two different dates).
The electric contractor guy was not too enthused about giving me any details about what I already had and what he suggested we change. I had purchased the building about a year or two prior and had no maintenance history records. He had a nifty little point and shoot device that could tell what type of fluorescent fixtures I had (13-15 foot ceilings). He checked a couple. I had already replaced some old broken ones with newer technology. But, he would not tell me which other ones would need replacing. He wanted the job to replace everything. The survey results were a bid for replacement. No details.
The insulation guy, again brought in by the power company, suggested added spray foam insulation on top of our vinyl covered fiberglass. We have a metal building. I asked what could be done with one of our uninsulated roll-up doors that faced the setting west sun (very, very hot in the summer). His suggestion was to spray over the door. And, if I ever decided to use the door again, he said it would be a simple matter of cutting the insulation off the roll-up door. YEAH, RIGHT!!!
Needless to say I did not use either of those two contractors. I essentially learned next to nothing from the power company surveys. We are serviced by a small power company, so they may not have the expertise on board for commercial evaluations. I think that this company was better prepared to perform residential surveys. Oh, well.
The morale of the story is two-fold: Do your own research, and find someone who really knows what they are doing and can show you how they got to their design for your building.
Best of luck in lowering your energy costs.