The corrugated medium and linerboard board are made of kraft containerboard, a paperboard material usually over 0.01 inches (0.25 mm) thick.
The panels contain cells made in China, Taiwan and, sometimes, Germany. Grape still plans to import inexpensive Chinese-made cells, and to buy Oregon-made inverters -- which convert direct current to alternating current -- for the panels it assembles in Eugene.
Solar cells are made of layers of semiconductor materials similar to those used in computer chips. When sunlight is absorbed by these materials, the solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity.