A 50 kw array under construction.

Building 3147: Here comes the sun

Construction started recently at the intersection of Fifth Street and Bethel Valley Road on a photovoltaic array—a solar panel—that’s going to be one of the largest and most efficient in the state. Its output will help power an entire ORNL office building.

The big solar panel will be 288 feet long by 10 feet wide and will generate 51.25 kilowatts at peak power. The solar collectors, made by SunPower and installed by Lightwave Solar Electric based in Nashville, are the best available, operating at 18.7 percent efficiency. For comparison, the array in the quad operates at 13 percent efficiency.

“If this array were constructed with the same modules as the one in the quad, it would have to be another 100 feet long to achieve the same electrical output,” says project leader Curt Maxey. “We are using the highest efficiency solar module with the highest capacity available.”

The power will be attached to the grid “node” that supplies the two-story Building 3147. Already an Energy Star-rated building, the structure will strive to become a zero-energy building by combining waste-heat recovery and other energy-efficiency techniques to offset the electrical load into the building.

Curt knows of two other arrays in Tennessee of similar size, one in Chattanooga and the other in Memphis.

“Power from this particular array will also be used to do research into power inverter technology and electric power distribution,” Curt says. “From the standpoint of our DOE sponsor, it’s good to demonstrate an actual, functioning office building as a component of the sustainable campus initiative.”