By MATTHEW DALY
WASHINGTON (AP) — A new federal report say solar energy has the potential to power up to 40% of the nation’s electricity within 15 years — a 10-fold increase over current solar output. But it would require massive changes in U.S. policy and billions of dollars in federal investment to modernize the nation’s electric grid. The report by the Energy Department’s Office of Energy Efficiency and Renewable Energy says the United States would need to quadruple its annual solar capacity. The report comes after President Joe Biden warned it’s time for America to get serious about the “code red” danger posed by climate change.