First you will need to pick which type of renewable resource you want to focus on; I am assuming from your question that you have selected solar energy. However, there are many types of solar energy. In order to write a process analysis, you will likely need to narrow your topic down even further. I would recommend selecting something simply, like solar panels, but there'd are many options. See the links below for more information on differs types of solar energy and renewable resources. Once you have narrowed your topic, you will want to find more information about how that example of solar energy works. If you were writing about solar panels, you would want to talk about how the sun's power hits the panel and is converted inside the solar cells. You will what to discuss how the sun's energy becomes usable, renewable electricity. Depending on how long you need your paper to be, you may want to address what makes this process renewable. I wouldn't get into opinions or comparisons to non-renewable resources though.