Arnaldo Vazquez cleans solar panels to maximize energy efficiency during the U.S. Department of Energy Solar Decathlon in Washington

 
Arnaldo Vazquez cleans solar panels to maximize energy efficiency during the U.S. Department of Energy Solar Decathlon in Washington
Student Arnaldo Vazquez from the Universidad de Puerto Rico cleans solar panels to maximize energy efficiency during the U.S. Department of Energy Solar Decathlon near the Washington Monument on the National Mall in Washington, October 10, 2009. REUTERS/Stefano Paltera/US Dept. of Energy Solar Decathlon/Handout (UNITED STATES EDUCATION ENVIRONMENT) FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS