The grid-supporting hydrogen house with full thermal and electrical supply

Project aim

FlexEhome is a publicly funded joint research project (BMWI, FKZ: 03EGB0025) with the goal of designing, constructing and evaluating a single-family house that covers its energy demand for electricity and heat at any time of the year exclusively through renewable energies used in the building and can additionally offer grid services to the surrounding electricity distribution network.


The motivation for the project arises from the challenge of improving future power grid flexibility. Due to an increasing share of renewable energies, the power grid must be able to react more flexibly than before to volatile feed-in characteristics. As an example of this development on the distribution grid level, the energy supply of residential buildings can be taken. For decades, only purely “consumer” buildings existed at the distribution grid level (cf. Fig. 1, left), which met their energy needs by drawing power from the grid. Nowadays, more and more buildings have become so-called “prosumer” buildings (cf. Fig. 1, center) with grid-connected photovoltaic systems, which not only draw electricity from the grid but can also feed it into the distribution grid in an unregulated manner. If the feed-in power of these “prosumer” buildings exceeds the power demand in the distribution grid, e.g. at the time of the midday peak, grid bottlenecks occur. Nowadays, these are mainly compensated by reducing the maximum feed-in power of individual photovoltaic systems. However, this means that renewable electricity is lost unused, which can be interpreted as a lack of power grid flexibility. Within , a highly flexible and thus grid-supporting operation is aimed at through the intelligent temporal use of energy storage (cf. Fig. 1, right), and this at every second of the year.

Figure 1
Integrales Raumwärmeangebot von Picea gegenüber der typischen Nachfrage eines KfW 40 Hauses mit 145 m² Wohnfläche am Standort Berlin

The Team

To achieve the project goals, experts from research (Hermann Rietschel Institute and the Department of Energy Technology and Environmental Protection at TU Berlin) and practice (homepowersolutions, Transsolar, Alberthaus and Vaillant as associated partner) have joined forces. Together, they cover the areas of highly accurate building simulation, intelligent control, hydrogen-based energy supply, holistic architecture and, last but not least, high-quality structural execution. Through this project team, the findings of the highly accurate simulation results will be used to build, measure and evaluate Germany’s first grid-connected single-family house with full electrical and thermal supply in Berlin


12/2022 Life Cycle Assessment of FlexEhome

The environmental sustainability of a building can be determined by life cycle assessment. The environmental impacts considered, in this case CO₂ emissions, are taken into account for the entire life cycle of the building. This means that CO₂ emissions are taken into account in all phases of a building, i.e.…

11/2022 Ground works started

It happens! Finally! Construction machines are aproaching and dig deep for providing a pit for the celler of the flexEhome.  Finest sand comes to light. Thanks to well insulated base plate the flexEhome is not entierly built upon sandy ground.


Mutual introduction of the partners Clarification of the two core objectives within FlexEhome Organizational

Project progress