The world's two largest rooftop installations of solar panels are now generating a combined total of 1.34 megawatts of electricity. Munich, Germany-based Siemens Solar GmbH has installed a photovoltaic plant on the roof of the New Munich Trade Fair Center. Consisting of 7,812 solar modules, the system will feed 1 million kilowatt hours of solar power into the grid of the facility. Solarex, Frederick, Md., will complete a photovoltaic rooftop installation this year at the Trade and Technology Center in Bonn, Germany. It will generate 500 kilowatt hours of solar power that will be fed directly into the grid of Stadtwerke, Bonn's utility company. Solarex's modules installed on the roof of Georgia Tech. University's Natatorium--the venue for the 1996 Olympic swimming and diving events--generate 344 kilowatts of power.