Several factors drive the interest in solar sites here. The price of solar power has fallen 70 to 80 percent, said Stephen Kalland, executive director of the N.C. Clean Energy Technology Center at N.C. State University. Large companies such as Amazon and Facebook seek to offset power use with renewable energies, he said. Lots of relatively cheap, flat, open land is available in northeastern North Carolina. Regulations have changed so that larger farms are more economical now, he said.