In 1905, Albert Einstein found a scientific explanation for the photovoltaic effect. Today, solar cells are producing more than 6,200 gigawatt hours of electricity per year in Germany alone. In contrast to solar thermal technology, photovoltaics (PV) do not use the heat radiated by the sun but its electromagnetic radiation (photons).
When photons hit a specially designed photocell, they move electrons in it and in this way generate electricity. The base material required to manufacture solar cells is silicon which is abundantly available in the form of quartz sand. Meanwhile, scientists are also experimenting with other materials for photocells.
The greatest potential of the capital city of Berlin lies on its roofs
At the moment, Germany is the leading nation when it comes to PV technology, both in terms of production and application. The driving force behind this development is the Renewable Energies Act (Erneuerbare Energien-Gesetz, EEG) which obligates power network operators to buy solar electricity at defined tariffs for a period of 20 years. The share of solar electricity is one percent of total final energy consumption.
The most commonly used solar panels are made of monocrystalline or polycrystalline silicon but increasingly so-called thin-film solar modules are also used in which the wafer-thin power-generating layers are applied to a carrier material such as glass. Therefore, the factors decisive for a plant's profitability are efficiency, module prices and, of course, the technical-structural preconditions. In Berlin, installation on roofs is almost the only option for solar power plants. In theory, the space available in the city is 45 million square metres but just a certain portion of this is actually suitable.
In particular in the case of larger plants on business, production or residential buildings, planning, installation and operation require appropriate technical expertise. In recent years, the Berliner Energieagentur has implemented several large-scale solar power plants on buildings in Berlin, including some prominent buildings. You can use our free solar power check to find out whether installation of a solar power plant will be technically feasible in the first place.