The U.S. Department of Defense opened its biggest solar array. This 16.4 megawatt solar farm located at David-Monthan Air Force Base in Tuscon, Arizona, will deliver 35% of the base's electricity needs and is projected to cut energy costs by $500,000 a year. The project is part of the U.S. Air Force effort to acquire 25% of its electricity from renewable sources by 2025. The Air Force spends over $9 billion annually on electricity and fuel costs, making it the largest consumer of energy in the U.S. federal government. The project, which includes a 25-year power purchase agreement with SunEdison, demonstrates benefits of public-private partnerships which were vital to financing construction of the array, allowing the air force base to acquire solar power at little or no upfront cost. Pew Charitable Trusts' recent research found that around 80% of future DoD renewable energy projects will be conducted through power purchase agreements similar to the one at David-Monthan. In other words, projects "that rely on private developers to finance, build, and maintain projects while saving military bases money over the life of the contract." Read more directly from the Pew website.