Solar energy, a form of renewable energy, contributes only .11% of total US energy as of 2012 according to era.gov. However, many believe that the recent advances in solar technology and the reduction in cost will see solar energy comprise 10% of total production by 2025.
Solar energy comprises photovoltaics (solar panels), solar collectors, and solar hot water heaters. There are many variations of these solar technologies dating back to the 1954, when the first solar panels were developed for NASA.
(CC Image courtesy of Michael Betke via Flickr)