Old Dominion Freight Line, based in Thomasville, N.C., is debuting a 160,000-square-foot rooftop solar panel system its warehouse. This is the third largest of its kind in North Carolina.

Old Dominion Freight Line teamed up with SunEnergy1, a solar energy firm, to make the rooftop solar panel system a reality.

The system, which has been operating since late December, can produce more than 2.2 million kilowatt hours of electricity a year -- enough to offset more than 90% of the building's electricity and greatly reduce Old Dominion's carbon footprint.

In total, there are 7,600 individual solar panels spanning the entire roof. That's enough electricity to power 200 homes annually.