Solar energy can be collected by photovoltaic systems (PV) or solar trough either. PV is working with total radiation, while solar trough or concentrated solar power systems (CSP) needs direct solar radiation only. But PV is losing efficiency, if the temperature goes up, while CSP as a thermal technology, is performing the better the hotter it gets. CSP is also known as the more economical technology, which can produce electricity for less than PV. While PV can produce electricity only, CSP can provide thermal and electrical energy at the same time. Therefore CSP systems are interesting for co-generation and process heat applications. They can be combined with other steam generator technologies, as there are biomass, biofuel, gas, oil and lignite. CSPs thermal energy can also be stored easier in buffer systems than electricity from PV in batteries. This allows having solar power also at night time.