Techno-economical optimization of solar energy supply concepts for residential buildings

The German energy transition must take place in the heat as well as in the power sector. In the field of solar energy, however, competition between solar-thermal systems and photovoltaic systems arises. A decreasing feed-in tariff leads to an increasing demand for solutions enabling self-consumption of energy. As a result, traditional heat generation systems, both fossil (e.g. gas heating boiler) and renewable (e.g. solar-thermal), enter a competition with systems being able to couple the electricity with the heat sector (e.g. photovoltaic + heat pump). The objective of this contribution is to analyze this competition and to evaluate the combination of solar-electric and solar-thermal systems in residential buildings. For this purpose, a linear optimization model is used. It also turns out that above all the investment costs for solar-thermal systems must fall, but also costs for battery storages are still too high. Only if several factors change, a combination of solar-thermal energy and photovoltaics becomes interesting from an economic point of view. For a reduction in emissions, the solar-thermal system competes with battery storage.