Solar electricity is a modern method of electricity generation: renewable and economical plus environmentally friendly and clean. Feed-in of solar-generated electricity into the public grid doesn’t produce any emissions and is therefore an excellent investment in the environment. In addition, it’s possible to produce very exact forecasts of the expected yields. Thereby, the risk for the investment in a PV system is reduced. Every photovoltaic system reduces the emission of greenhouse gases by saving coal, oil and natural gas. A 1 kWp solar electricity system avoids annually 800 kg of carbon dioxide (German norm). After expiration of the 20-year feed-in guarantee, the legislators will, with high probability, enact a framework to continue to use the potential of existing grid feed-in systems. The then effective electricity price would be surely conceivable as a lower limit for the feed-in tariff; the electricity price is currently a bit lower than 20 cents per kilowatt-hour. At long-term above-average increase of the electricity price in comparison to the present, caused by further scarcity of fossil fuels and the nuclear phaseout, photovoltaic operators can anticipate above-average additional income.