from: [1] http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en549769 

As the world is more and more concerned with fossil fuel exhaustion and environmental problems caused by conventional power generation, renewable resources are becoming a focal point of the environmental movement, both politically and economically. Such renewable resources includes photovoltaic (PV) and wind generation systems. Using renewable resources on a large scale is a cost problem and in most cases, more research is needed to make their use cost-effective. PV systems, also termed solar microinverters, have gained greater visibility during the past several years as a convenient and promising renewable energy source. These energy systems have several advantages compared to other forms of renewable power, such as wind energy. [2] Read more.