Los Angeles is at the center of small surge in solar energy use. The L.A. Convention Center, which housed the Democratic convention earlier this month, has installed 15,000 square feet of solar panels and has plans for more. City Hall and the Department of Water and Power are next, and the zoo is designing a new entrance made of solar panels. On a national level, the U.S. Energy Department is asking architects to incorporate solar features into their blueprints and working with developers to construct homes that are 50 percent more energy-efficient without adding to the sale price. The most environmentally friendly public school in Washington state opens today. The elementary school in Kent, Wash. is partially powered by solar and wind and warmed by geothermal heat, and it includes a stormwater collection-and-reuse system for irrigation, as well as waterless urinals expected to save about 144,000 gallons of water a year.