An exhibition staff shows how to install the household rooftop solar panels at the Solar Power International (SPI) 2016 exhibition in Las Vegas, the United States, Sept. 13, 2016. The Solar Power International (SPI) 2016 exhibition kicked off at the Las Vegas Convention Center on Tuesday with thousands of solar professionals rolling into the city. The event -- the largest of its kind in North America -- has so far attracted 16,000 visitors and around 600 exhibitors and is co-sponsored by the Solar Energy Industries Association (SEIA) and the Smart Electric Power Alliance (SEPA). (Xinhua/Zhang Chaoqun)
