Eigendeckung des Strombedarfs von Niedrigstenergiehäusern durch Photovoltaik-Anlagen - Verrechnung mit unterschiedlichen Zeitschrittweiten ergänzend zur EnEV

On-site electricity coverage by PV systems of nearly zero energy buildings and its estimation for various time steps in addition to the German EnEV.

Model calculations are executed to analyse three nearly zero-energy buildings (single-family house, terraced house, apartment building) with passive house insulation and heat pump supply system. The suitable roof areas of the buildings are covered by PV systems. The focus of the analysis is to determine which part of the generated electricity can be directly used in the building (without battery buffer) and to what extent this fraction is depending on the time interval of compensation between electricity generation and demand. A parameter variation is revealing the dependence of the on-site coverage factor from the type of building, from the insulation standard and from the consideration of household electricity.
A core result is that the method of the German energy saving ordinance (EnEV) is overestimating the fraction of electricity demand which can be covered by on-site electricity production and that this can lead to misoptimisations of buildings from the viewpoint of consumers but also from the perspective of a future energy supply sector. By the derived simplified method a possibility is introduced to make an ex-post estimation of the on-site electricity coverage for time steps which are smaller than have been used in the given energy demand calculation. Starting from the methodical aspects for calculating the on-site coverage fraction possible ways for further development of the EnEV requirement and energy certificate calculation procedure are discussed, taking into account the specific features of nearly zero-energy buildings and their role in a future energy supply system that will primarily be based on renewable energy sources.