Boise — The J.R. Simplot Co. is among six major U.S. companies to join the Better Buildings Challenge and commit to reducing energy use in their facilities by at least 20 percent by 2020. Simplot has committed to improving energy efficiency at its 16 U.S. manufacturing plants by 25 percent over 10 years. Four of them have already improved by 25 percent the last three years. The company has driven waste from processes, trained employees in best practices, worked with communities, and partnered with suppliers to do so.