Elobau’s energy vision, to be carbon-neutral for its operations, set the tone for the design of its new production hall. To help achieve this vision, it was clearly necessary to use 100% on-site-generated renewable energy. Transsolar’s task was to ensure that electrical energy supply would always be available to cover the demand. What is most innovative about this project is that the majority of this site-generated electricity is stored on site in Li-ion batteries to buffer instantaneous swings of generation and demand; the site-generated electricity is not fed back into the grid.
For this project, it would be fairly straight-forward to accommodate a renewable energy generation system to offset 100% grid electricity on an annual basis, but to ensure that renewable energy supply is always sufficient on an hour-to-hour basis, energy storage is necessary. Demand-controlled power generation makes little sense: there are sudden peaks in demand, and solar and wind energy are, by nature, transient. In this case, batteries were selected to decouple the disparate supply and demand loads.
Most buildings with on-site renewable energy systems are connected to the grid, so that electricity generated in excess of on-site demand can be fed into the grid. However, to have the smallest environmental footprint possible, it is better to use the site-generated electricity on-site, to minimize energy losses.
For this production hall, load profiles were created from measured data from current production halls and simulation results. Options with various combinations of PV and battery sizing showed that the PV panels would have to be sized for 150% of the building’s electricity peak, in order to cover 80% of the yearly energy needs of the building and to be financially feasible.
Not only has the environmental impact of the building operations been carefully considered, impact of the building construction has been also minimized: it has a wood construction; its location on previously developed land means that undeveloped land can remain natural and untouched.
Some PV panels are installed at grade, adjacent to the building. The foundation of the PV panels act as geothermal heat exchangers and work in combination with a heat pump to supply the building with heating and cooling. PV on the roof and at grade generate about 220 MWh per year.
Award: Staatspreis des Landes Thüringen für Architektur und Städtebau 2018