A yearlong study by the Department of Energy has concluded that when consumers are given the means to closely track and adjust their energy usage, power use declines by an average of 10 percent. In addition, the study found that households’ electricity usage during peak times fell by up to 15 percent. The study estimated that “smart grid” technology, if used nationwide, could save some $120 billion in unneeded power plants and transmission lines, and over a 20-year period could displace the equivalent of 30 large coal-fired power plants. “This research is vital because decreasing power consumption during the busiest times on the power grid improves efficiency and reliability and reduces the need to build additional infrastructure,” said Sen. Patty Murray (D-Wash.).